Advanced Framing Wood Efficiency

8/18/2019 Advanced Framing Wood Efficiency

1/31

Advanced Framing: Using

Wood Efficiently FromOptimizing Design toMinimizing the Dumpster Research Report - 02012002 August by Steven Baczek, Peter Yost and Stephanie Finegan, BuildingScience Corporation

Abstract:

Americans have been building homes with wood—shaping logs, joining timbers, nailing studs—for

almost 400 years. Our current approach, stick framing, grew popular in the mid-1800’s (particularly

in the rapidly growing “West”) because it took less skill, required simpler tools, and took fewer people

than timber framing. We apparently really like waste haulers, too. The NAHB Research Center

reports that the “typical” home generates about 3,500 pounds of wood waste during its construction,about half of which is solid sawn lumber.

building science.com© 2006 Building Science Press All rights of reproduction in any form reserved.


2/31

1 © 20 02 Bui ld in g Sc ie nc e Co r po r at io n

Set t ing t h e St age

A m ericans h ave been bu ildin g h om es w ith

w ood—shap in g logs, join in g tim bers,

n ailin g stu ds—for alm ost 400 years. O u r

cu rrent approach—stick-fram in g—grew

pop u lar in th e m id-1800’s (particu larly in

th e rapidly g row in g “W est”) becau se it

took less skill, requ ired sim pler tools, an d

took few er people th an tim ber fram in g.

W e still like bu ildin g h om es w ith w ood .

A ccordin g to th e N A H B R esearch C en ter’s

A n n u al B u ilder P ractices Su rvey - 199 9,87.7% of th e 1 .7 m illion h om es bu ilt th at

year, sin gle-fam ily an d m u lti-fam ily, w ere

stick-fram ed.

W e also like bu ildin g w ith lots of w ood. Th e

N ation al A ssociation of H om e B u ilders

(N A H B ) reports th at a “typ ical”hom e

tak es ju st over 13, 100 board feet of

lu m ber. Th at’s abou t th ree-qu arters of an

acre of forest ju st for fram in g lu m ber.

Using Wood Ef f i c ient l y:Fr om Opt imi zing Desi gn t o Mini mi zing

t h e Dumpst er

“Wood is good, be it used as it should.”

Anonymous Amish carpenter

Steve Baczek, Peter Yost and Stephanie Finegan

W e apparen tly really like w aste h au lers, too.

Th e N A H B R esearch C en ter reports th at th e

“typ ical”hom e gen erates abou t 3,50 0 pou n ds

of w ood w aste du rin g its con struction , abou t

h alf of w h ich is solid saw n lu m ber.

So, let’s do th e m ath for U S h om e bu ildin g

each year (assu m in g th at 19 99 is a

represen tative year, w h ich it w as, ju st

sligh tly above the averag e over th e last 5

years):

1.ju st u n der 1.5 m i l l ion homes stick -

fram ed,

2.consum in g just u n der 2 bil l ion board

feet of fram in g lu m ber, an d,

3.gen eratin g ju st u n der 1.3 m i l l ion tons

of solid-saw n w ood w aste (th row in

an oth er m illion plu s ton s of en gin eered

w ood w aste—m ostly plyw ood and O SB —

for good m easure).

Figure 1Early efficient fra ming diagra m.

One th eory of the or igin of the

term “balloon” framing is th at i t

was a der ogator y term given,

probably by timber fram ers, to

buildings so fra med tha t would

“float away.” This plate is ta ken

from a book entitled Carpentry

Made Easy, William Bell, 18 58 .

Figure 3Disposal or

delivery ? This

is wood was te

paid for 3 times:

purchase, site

handling

(several times),

and disposal.

Figure 2Wher e one

st ud is good,

two must be

better, and 9

must be the

ultima te. This

is MVE —

minimal value

engineering.


3/312 © 2 00 2 Bui ld in g Sc ie nc e Cor po r at io n

Laying out t h e oppor t un i t ies

Th ere are opp ortu n ities to u se w ood m ore efficien tly at every

stage of a hom e’s design an d con stru ction —you cou ld call th is

optim u m valu e en gin eerin g (OV E ) from start to fin ish. M ost

people th in k of O V E as a m eth od of w ood fram e con struction ,

lim itin g th e con cep t to ju st a p art of th e total bu ildin g process.

B u t O V E is gettin g th e m ost ban g for your bu ck throughout th ebu ildin g process.

Lots of bu ilders ju st don ’t like the term O V E , regard less of h ow it

is u sed . It im plies ch an ges or solu tion s offered to b u ilders b u t

n ot by bu ilders. Th rou gh ou t th is paper, every w ood efficien cy

con cep t is supported by B u ildin g S cien ce C orp oration ’s field

ex perien ces un der th e D epartm en t of E n ergy’s B u ildin g

A m erica p rogram . B u ildin g A m erica is all abou t takin g ideas

from th e office to th e field w ith ou r n ation ’s leadin g prod u ction

bu ilders. Th at’s from b u ilders, for

bu ilders, period .

M an y aspects of efficien t u se of w ood are in ter-related,

com plicatin g or even con fou n din g categorization . W e fin d it

u sefu l to layou t th e opp ortu n ities in th e follow in g w ay:

• design an d layou t

• m aterial selection s an d pu rchase

• delivery an d on -site storage

• fram in g techn iqu es (in clu din g an in n ovative n ew shear

pan el)

• w aste/disposal (in clu din g an in n ovation called th e

SEE stud)

W e say opp ortu n ities becau se, m ore often th an n ot, u sin g w ood

m ore efficien tly saves tim e, m on ey, en ergy, an d resou rces—for

you , you r cu stom er, an d you r com m u n ity. G iven its goals, th is is

w h y w ood efficien cy h as been such a good fit for th e B u ildin g

A m erica program . (See case stu dies on pages 18 — 26 .)

Design and Layout

Th ere certain ly is a lot m ore to con sider in h om e design th an

fram in g efficien cy; th ere are aesth etics, m arketability, u tility,

an d sitin g, ju st to m en tion a few . B u t fram in g efficien cy d oesn ot h ave to com e at th e ex pen se of th e oth ers. A reasonable

balan ce can resu lt in efficien t an d beau tifu l bu ildin gs. E fficien cy

does n ot m ean forcin g it in to every n ook an d cran n y of you r

design ; it m ean s em ployin g an y or all of th e techn iqu es below

w hen it m akes sen se an d cents.

W e h ave grou ped design an d layou t togeth er because w e feel

th ere is a n atu ral an d in ex tricable relation ship betw een th e tw o.

Th e design in form s layou t, bu t w e th in k th at th e reverse shou ld

Syst em Benef i t s of Us ing Wood Ef f ic ient l y

A s you w ou ld expect, efficien t u se of w ood

m eans you buy less w ood an d save on

mater ial costs -- th e B u ildin g A m erica

bu ilders from th e case stu dies on pag es 18 -

26 saved in th e n eigh borh ood of $450 to

over $1 ,10 0 per hou se in lum ber and

sheath in g pu rchases (th is does n ot in clu de

the difficu lt-to-qu an tify-bu t-sign ifican t labor

savin gs associated w ith h an dlin g, cu ttin g,

an d in stallin g less lu m ber, by th e w ay).

B u t th e savin gs an d valu e don 't stop th ere:

•Improved thermal performance - an y

in sulation m aterial perform s a

m in im u m of th ree tim es better th an

w ood, so less w ood m eans m ore en ergy

savin gs for th e h om e ow n er. Take a look

at th e Centex Homes a nd Pulte Homes

Case Studies .

•Reduced callbacks - few er cold spots

(particu larly at ou tside corn ers) an d the

redu ced stress associated w ith few er

poin ts of con tact betw een fram in g an d

gypsum board cut dow n on one of the

m ost com m on an d expen sive callbacks--

dry w all crackin g.Building Americapartner Tow n an d Country Homes of

C h icago, Illin ois reports dryw all

callbacks dropp in g from betw een $1 ,200

an d $ 1,50 0 to on ly $ 15 0 p er h ou se w ith

th e sw itch to an advan ced fram in g

package.

•Reduced disposal cos ts - G reater

efficien cy m ean s less w aste an d low er

disposal costs. C h eck ou t th e

com prehen sive approach of B u ildin g

A m erica bu ilder Artist ic Homes.

•Reduced environmental impact - few er

trees cut, h om es th at u se less en ergy

an d last lon ger, an d less m aterials sen t

to local lan dfills all tran slate in to

"greener" h om es an d sign ifican t pu blic

en viron m en tal ben efit. C h eck ou t w h at

th is has m ean t at th e B u ildin g A m erica

project,Prairie Cross ing.


4/31


be true as w ell. It represen ts

th e good fit th at can ex ist

betw een arch itectu re an d

en gin eerin g in residen tial

bu ildin gs.

• Footprint

E very jog added to a squ areor rectan gu lar bu ildin g

footprin t can challen ge

fram in g efficien cy, som e

m ore th an oth ers. Th e

trick is to in clu de fram in g

m aterial an d fram in g

layou t con sideration s

during bu ildin g d esign . It

is possible to en gin eer an

elegan t h om e, bu t on ly if

th e fu ll ran ge of stru ctu ralm aterials an d th eir

properties are an

in ten tion al part of th e

design process, n ot an

afterth ou gh t.

• Dimensions

R eal estate developers

often play a gam e of in ches w h en it com es to room

dim en sion s, bu t it is easy to satisfy bu yer expectation s

regardin g room sizes an d still u se m odu lar design .

M odu lar d esign is basically u sin g tw o-foot in crem en ts

as often as p ossible, tak in g fu ll ad van tag e of th e

m aterial dim en sion s su pp lied by th e m an u factu rin g

in du stry, particu larly sh eathin g good s an d large

fram in g m em bers. In gen eral, it m akes m ore sen se to

optim ize for outside dim en sion s and h en ce fram in g/

w ood sheath in g m aterials th an it does to op tim ize for

in terior dim en sion s.

Figure 4

Metro Denver Habitat for HumanityDenve r, Colorado

14 homes built

Floor plan with duct layout a nd

wall elevat ions

Figure 5

Town & Country Homes

Centennial CrossingVernon Hills, IllinoisA fra ming plan can do more than just lay out floor joists. There

ar e opportunities t o value engineer the floor sys tem and obtain a

proper joist count, to ensur e all plumbing is coordinated with th e

floor fr amin g, to en sur e all HVAC is coordin ate d with t he floor

framing, and to ens ure th at th e “st ack framing” concept is

followed on the job site. Most impor ta nt ly, all thes e issu es a re

res olved on paper pr ior to cast ing the foundation.



Figure 6

Prairie Holdings

Prairie CrossingGrayslake, Illinois

199 bui l t / 131 planned

The two plans t o the right il lust ra te

an inter esting compar ison in ter ms of

overall building footprint and its

relationsh ip to wood frame const ruc-

tion. Both plans a re from a Building

America Development at Prair ie

Crossin g in Gra yslake Il. The t op

figure a t r ight is a four bedroom plan

with approximately 2,300 square feet

of floor ar ea. The bott om figur e at

right is also a four bedroom plan with

approximately 2,500 squar e feet of

floor a rea . Although ver y similar in

function and floor area , the bottom

plan poses a dditional challenges t o

the builder a nd to the performan ce of the house: twice as many walls to

build and coordinate, 89 feet more

wall to build (to be exact ), and 7 55

more squar e feet of wall to batt le heat

loss and h eat gain. We ar en’t

advocat ing box building, but dimen -

sional considerations s hould have a

role in the design process.

D escription 2,300 Ft2 2,50 0 F t2

N um ber of fram ed E x terior W alls 12 28

Lin ear Footage of E xterior W all 314 lf 403 lf

Surface A rea of Exterior W all 2,670 ft2 3,425 ft2


6/31


• Integration of des ign w ith framing and the HVAC sy stem

Th e perform an ce, com plexity an d even th e exp en se of th e

H VA C system can be d riven by its relation ship to fram in g

layou t an d d esign , particu larly w ith respect to du ct layou t.

Som e foreth ou gh t abou t w all location s, direction of floor

fram in g, an d d epth an d type of floor fram in g m em bers can

resu lt in som e beau tifu l syn ergy betw een th e fram in g an d

H VA C system s. Its absen ce can brin g fram in g an d

th erm odyn am ic chaos, an d all for n o particularly g ood

reason . See Figure 5 for an exam ple.

• Detai led f raming plans

It pays to do detailed fram in g plan s, both as a dou ble-check

on op portu n ities for efficien cy g ain s from sm all design

m od ification s back at th e office, an d as detailed gu idan ce for

Figure 7Artistic Homes

Albuquerque, New Mexi co

1,066 homes

Although labeled by some as tedious and labor intensive, wall framing elevations have a great deal to offer. In Figure 7 the wall framing

elevations s how the location of all shea r pan els, the location of any a ir bar riers , the location of header s (a nd no header s), and all the

run ning dimensions for window layout. The elevations also offer the ability to properly estimate a ma terial count ( remember less was te).

Although relevant for all builders, wall framing elevations really makes sen se for production builders where a house may get built twent y

or thir ty times. A 16 hour design effort drafting the wall elevations accounts for less than an hour per house built . The est imator a nd lead

car penter would spend four times th at in head scr atching alone without wall elevations.

th e fram ers at th e job site. W e h ave

fou n d th at detailed fram in g p lan s m u st

m ak e it to the job site, particu larly w h en

elem en ts of efficien t fram in g are n ew to

th e crew or crew s. A n d, th ere is n oth in g

w orse than a m andate com in g from the

h om e office abou t efficien t u se of w ood

accom pan ied by design s an d layou ts

th at m ak e efficien t fram in g difficu lt,

cryptic or even im possible. D etailed

fram in g plan s can m ake th e difference.

(D etailed fram in g p lan s don’t h u rt w ith

local bu ildin g officials either, givin g

th em advan ce notice and h eadin g off

subsequ en t approval issues.)



Mat er ia l Sel ec t i onsand Pur chase

Som e m aterials in h erently m ake better use of w ood resources

th an oth ers; som e m aterials com e from in h eren tly m ore

resou rce-efficien t sou rces. Th is provides tw o m ore opportu n ities

to op tim ize you r use of w ood resou rces.

• Engineered wood products ( EWPs)

A n y w ood prod u ct th at derives at least som e of its

structu ral prop erties from m ore th an ju st n atu ral w ood

fiber or solid-saw n lu m ber is an en gin eered w ood produ ct.

Th ey all con tain adh esive or m echan ical fasten ers, or both .

E W P s ten d to be m ore con sisten t in th eir perform an ce

prop erties th an th eir solid-saw n cou n terparts; less toleran t

of site m od ification s; an d m ore flexible in ex ten din g design

beyon d w h at is possible w ith solid-saw n cou n terparts. In

recent years, m an y E W P s have becom e very com petitive in

price w ith solid-saw n cou n terparts.

B ecau se E W P s (ex cept plyw ood ) u tilize sm aller, faster-

grow in g trees, th ey can relieve pressure placed on m ore

en viron m en tally sen sitive old-grow th resou rces. (W ith th e

exception of som e pressu re-lam in ated th in fiberboard

sheath in gs su ch as Th erm oP ly“, n o structu ral E W P s

cu rrently bein g produ ced u tilize an y recycled w ood .) E W P s

ran ge from orien ted stran d b oard (O SB ) to floor an d roof

trusses, to h orizon tal fram in g m em bers such as I-joists,

lam in ated ven eer lu m ber (lvls), an d glu lam beam s. Th eir

u se can in crease spacin g sch edu les, yield d eeper fram in g

cavities for accom m odatin g m echan icals, an d result infew er problem s w ith th e cross-w idth shrin kag e com m on in

deeper solid-saw n fram in g m em bers. A lth ou gh it is alw ays

possible to u se an y w ood resou rce in efficien tly (in clu din g

E W P s), E W P s gen erally represent th e opp ortu n ity for m ore

efficien t w ood u se.

• Wood products from s ustainably harve sted s ources

A s a ren ew able resou rce, w ood h as in h erent resou rce

efficien cy. B u t th ere is qu ite a ran ge of h arvestin g practices,

w ith in an d beyon d th e U n ited States. True ren ew ability

n ecessitates harvestin g practices, replan tin g, an d forest

diversity m ain ten an ce th at sustain th e resou rce. Th ere are

cu rren tly fou r forest certification program s active w ith in

N orth A m erica—the A m erican T ree Farm System , the

C an adian Stan dard A ssociation ’s (C SA ) Su stain able Forest

M anagem ent Program , the Forest Stewardsh ip Counci l

(FSC) program ( h ttp://w w w .fscoax .org), an d th e

A m erican Forest an d P aper A ssociation’s (A F& PA )

Su stain able Forestry In itiative. O n ly on e program —

the FSC -certified prog ram —requ ires th ird-party

certification , ch ain of cu stod y

docu m en tation , an d produ ct labelin g;

attribu tes th at w e th in k are cru cial for

lon g-term efficien t w ood u se. B u t ju dge

for you rself—all of th e p rogram s

represen t sign ifican t dep artu res from

lon g-stan din g u n sustain able h arvestin g

practices an d can be com pared:h ttp://

w w w .certifiedw ood.org/in dex.h tm . Th is

site also in clu des a n ation w ide sou rcin g

database for FSC -certified w ood

produ cts. Th e availability of F SC -certified

solid-saw n w ood prod u cts is still lim ited

bu t defin itely grow in g; on th e E coVillag e

C levelan d B u ildin g A m erica p roject, w e

h ad n o trou ble specifyin g F SC -certified

lu m ber in term s of availability or im pact

on th e bu dget.


8/31


Del iver y and On-Sit e St or age

It’s pretty easy to ju st lay th is ou t in sim ple term s—on ly deliver

to th e job site ex actly w h at you n eed an d th en treat th e

m aterials w ith respect once th ey arrive.

• Wast e factors

You alw ays n eed to p ad th e lu m ber take-off w ith a “w aste”

factor, to accou n t for bad stock an d labor errors on th e job

site. B u t th e qu estion is: w h at w aste factor is reason able—is

it 5% or 1 5% of th e tak e-off? O n e job site proverb app lies

h ere: you sen d it, w e will u se it. O n ly you kn ow ju st h ow

closely you can set th is factor, bu t detailed fram in g plan s

can w ork w ell w ith a h on ed-dow n w aste factor. A n d som e

bu ilders are exp erim en tin g w ith color-codin g or som e oth er

w ay of design atin g stock so that th ere is an easy w ay for

everyon e from th e site su per to the carpen ter’s h elper to

kn ow for w h at u se each stick w as in ten ded.

•Dunnage and Coverage

It’s pretty am azin g to see h ow disrespectfu lly lu m ber

packages can be treated on th e job site—lifts sittin g in m u d

or pu dd les of w ater w ith n o top cover. W h y p ay for kiln -dried

stock an d th en treat it like lan dscapin g m aterial on ce it gets

to th e job site? T h e perform an ce of w ood produ cts —

particu larly sh eet good s — can su ffer if left ex posed.

P rotectin g w ood produ cts on th e job site prior to th eir u se is

cheap an d sim ple—stick th e load to k eep it u p off th e grou n d

an d top cover. It w ill rem in d you r fram in g crew th at th ey

w ork w ith valu able produ ct an d sh ow you r poten tial

hom ebuyers how you m anage w hat could soon betheir

m aterials.

Figure 8 bThis is the way to

s to re mater ia ls on

the job site.

Figure 8 aThis is n ot the way

to s to re mater ia ls

on the job site.



Fr ami ng Tech ni ques

N ow to th e n u ts an d b olts of u sin g w ood efficien tly. M an y of

th ese techn iqu es sh ou ld be illu strated in you r fram in g plan s,

plan s th at m ak e it to th e job site for crew h ead -scratchin g, or

referen ced in you r job site fram in g specs by w ay of th e

ap propriate EEBA Builders Guide (see R esou rces).

W e see ju st tw o g en eral prin ciples of efficien t fram in g:

Principle # 1

U se stru ctu ral grade m aterials to their fu ll ap proved

capacity. A ready ex am ple w ou ld be u sin g 2 4-in ch on cen ter

fram in g “stacked”from fou n dation to roof.

Principle # 2

D on ’t u se stru ctu ral grade m aterials in n on -stru ctu ral

application s if oth er m aterials can accom plish th e requ ired

fu n ction (s). A ready exam ple w ou ld be a d ryw all clip in stead

of an extra stu d for dryw all back er in ou tside corn ers.

B u t th ere is a m yriad of specific w ays to app ly these prin ciples.

W e have tried to present th em h ere rough ly prioritized in term s

of relative con tribu tion to w ood efficien cy:

• Stacked framing greater than 16 inches on cen ter

Th is tech n iqu e is actu ally a com bin ation of related adv an ced

fram in g m eth ods. W h ile each can be em ployed in dividu ally,

th ey do m ake sen se to con ceptu alize an d u se as a system :

1 . in creased spacin g –m ovin g from 16 in . O C to 2 4 in . O C

represen ts th e sin gle largest w ood fram in g savin gs.

Th is is becau se it in volves n ot on ly w all stu ds, bu t deep

m em bers su ch as floor joists or roof rafters as w ell.

2. in -lin e fram in g –this m ean s align in g, from roof to sill

plate, all fram in g elem en ts -rafters (or tru sses), bearin g

w all studs, floor joists.

3. sin gle top p late –if bearin g fram in g m em bers are all

align ed, th e structu ral n eed for m ore th an on e top plate

is elim in ated. Th e practical n eed for tyin g togeth er th e

top plates of lon g

ex terior w alls or

in tersectin g in terior

w alls, an d for

straigh ten in g th e tops

of w alls, can be

accom plished w ith

m etal stitch plates.

• Insulat ing sheathing

A chievin g requ ired sh ear resistan ce in w alls w ith m etal

ban d bracin g in stead of structu ral pan els n ot on ly saves a

lot of w ood, it perm its th e u se of

con tin u ou s rigid in su lation in place of

O SB or plyw ood . Th is boosts overall R -

valu e of

th e w all,

im proves

air

tigh tn ess,

and m oves

th e first

conden sin g

surface ou t

of th e w all

assem bly.

• Load-tuned headers for window and

door openings

It’s n ot u n u su al to see all open in gs in a

bu ildin g h eaded off w ith a on e-size-fits-all h eader. It su re m ak es it easier for th e

fram in g crew , bu t at w h at a cost! It’s

certain ly con ven ien t to keep th e d epth

of th e header th e sam e as m uch as

possible, bu t tu n e th e h ead er w ith

differen t m aterials or con figu ration s

(sin glin g/dou blin g). O n ce again , detailed

fram in g

plan s can

m ake

optim izin gheader

configurations

a relatively

easy

ex ercise

for the

fram in g

crew .

• Reduced use of cr ipples , jacks , and

dryw al l backer studs

W e often u se

structu ral

grade tw o-

bys for non -

structu ral

w all

fram in g:

supp ortin g

dryw all at

State Department of EnergyMantachie, Missis sippi

12 demonst ration homes

Town & Country HomesCentennial Crossing

Vernon Hills, Illinois

GreenBuilt Homes

City infillCleveland, Ohio

2 prototype homes


10/31


corners, providin g en ou gh n ailin g for w in dow an d d oor

casin gs, an d m akin g assem bly of w in dow roug h open in gs a

bit easier w ith en d cripp les. Th is can be m ore th an ju st an

efficien t u se of w ood ; it can m ean u n n ecessary cold spots in

exterior w alls an d sub sequen t dryw all pop s an d crackin g.

Th e best bet is to save grade-stam ped structu ral lu m ber for

structu ral application s, an d em ploy m ore valu e-en gin eered

m ean s —dryw all clips, ladder b ackin g, etc.— to support

oth er fu n ction s.

• Truss or EWP roof fram ing

U sin g solid-saw n lu m ber for roof fram in g is often a

qu estion of region al preferen ce or con ven tion . B u t w ith

truss plan ts n ow operatin g in every reg ion of th e cou n try,

an d I-joists that can w ork as w ell tilted u p as lyin g flat, th e

n u m ber of application s th at requ ire th e u se of solid-saw n

deep roof fram in g sh ou ld be n early n il.

• Two-foot modular des ign and layout

Startin g w ith fou n dation layou t,

th e h ou se footprin t can be based

on tw o-foot in crem en ts, often

w ith sign ifican t savin gs

in both fram in g

m em b ers an d

sheath in g an d alw ays

w ith a lot less w aste. W e

on ly list th is last

because w ork b y the

N A H B R esearch Center

a nu m ber of years ago

fou n d th at th e w ood

savin gs can be very

depen den t on the

startin g dim en sion s.

• Inse t shear pane l

H ere is a great

exam ple of w h en th in kin g “ou tside th e box”really m ean s

“in side the fram e!” A ll h om es reg ardless of location requ ire

som e level of sh ear resistan ce. B u ilders in active seism ic

an d h igh w in d zon es have tw o particular advan ced fram in gproblem s:

1. Sh ear resistan ce requ irem en ts m ean th at h igh

perform an ce bu ilders can ’t reason ably u se con tin u ou s

in sulatin g sh eath in g in place of plyw ood or O SB pan els.

2. Th e sam e shear resistan ce requirem en ts often m ean

th at exp en sive, prop rietary, m an u factu red shear pan els,

such as Sim pson Stron g-W all Sh earw alls or H ardy

Fram e pan els, m ust be used.

A s a part of th e B u ildin g A m erica

program , an d w orkin g w ith P ulte H om es

of Tracey, CA ; th e A rm y C orps of

E n gin eers’Civil E n gin eerin g R esearch

Laboratory (C E R L); an d A TI A rchitects

an d E n gin eers; B u ildin g S cien ce C orp.

h as su ccessfu lly develop ed, tested, an d

field-in stalled in n ovative inset shear

pan els th at can be site- or sh op -

assem bled.

Th e p an els are design ed to fit righ t in to

th e advan ced fram in g app roach—tw o by

six w alls fram ed 24 in . O C w ith sin gle

top plate an d stacked fram in g. A n d,

becau se th e p an els are in set, con tin u ou s

rigid in su latin g sh eathin g can be

em ployed . Th e result is a h igh -

perform an ce fram in g assem bly, both interm s of shear and en ergy perform an ce.

Th e estim ated con struction cost of site-

bu ildin g on e 4 by 8 in set shear pan el is

approx im ately $ 100 to $1 50, far less

th an th e cost of th e m an u factu red

pan els. Sh opbu ildin g th ese pan els w ou ld

brin g econ om ies of large scale

prod u ction an d low er th eir cost even

fu rth er. A B SC ap plication for an

In tern ation al C on feren ce of B u ildin g

O fficials (IC B O ) Evalu ation ServiceR eport, key to com preh en sive bu ildin g

code acceptan ce of th e in set shear pan el,

is pen din g.

Pu lte H om es has em ployed the in set

shear pan els in tw o prototype h om es

an d is usin g th e pan els at B eacon Poin t

in 74 hom es currently u n der

con struction .

Figure 1 0

In this one photograpfrom a Building Amer

project at in the m id

ther e a re FIVE effici

framing techniques. S

you can name t hem a

check your answer s

against the l is t in th

footnote* .

4 ’

4 ’

4 ’

4 ’

4 ’

2 4

- i n c h

g r i d

4 ’

4 ’

2 4 - i n c h g r i d

2 4 - i n

c h g r i d

2 4 ” 2 4 ” 2 4 ”

2 4 - i n c h g r i d

Plywoodsoffit

16”

2” ventstrip

4’

8’

16” 16” 16”

2 strips of plywood4 feet wide and

1 strip 2 feet wide

2’-10”

16’-2” *

9’-7”

19’-2” *

1 0 ’ - 0 ”

2 4 i n c h g

r i d

Cut plywoodsheet into equal

strips for soffitassembly. Paint/ seal upper andlower surfaces ofsoffit as well asedges.

18” overhang

* Note: The 2”dimension comesfrom assumingthat 1” thickinsulatingsheathing isinstalled overframing.

Figure 9Efficient mater ial use by design

* l o a d - t u n e d h e a d e r , i n - l i n e f r a m i n g , 2 4 - i n c h O C , s i n g l e t o p p l a t e , a n d o p e n - w e b t r i m m a b l e f l o o r t r u s s



Figures 11Shown her e is the s hop drawing, str uctur al testing, and field inst alla-

tion of an ear ly prototype of an inset shea r pan el. The panel was us ed

success fully in a Pulte home in J acksonville, Florida, under the

Building America program. Note the continuous rigid insulation

sheathing. This prototype led to the development of the panel illus-

tr ated below (Figure 11).

Figures 12

Shown her e is the t wo-stor ystr uctur al testing, shop drawing, and

field insta llation of the inset shea r

panel s ubmitt ed for ICBO. The phot o

of a Building Amer ica h ome in

J uneau, Alaska shows the r eal

meaning of “pictur e perfect

framing!”


12/31


Wood Ef f i c iency:

I t ’s not j ust ab ou t

t h e Fr amer

Th ere are a lot of

really top-n otch

bu ilders ou t th ere

w h o feel th is w ay

ab ou t efficien t

fram in g:

“The arch itect an d

fram er better n ot

fin e-tu n e th e

fram in g too m uch;

you h ave to bu ild in

qu ite a bit of slack

to m ake up for

w h at w ill h app en

w hen the plum ber,

electrician , H VA C

con tractor an d

dryw aller are don e

w ith it.”

That’s w h y th e

B u ildin g A m erica

approach to w ood

efficien cy is so

im portan t — it’s

an in tegrated

system s

app roach in

w h ich A LL of the

trades an d th e

system s in th e hom e for w h ich th ey are

respon sible h ave to w ork togeth er. Trades

th at run th in gs u n der, th roug h an d

aroun d the fram in g — plum bers,

electrician s, in su lators, an d H VA C

Artistic Homes

Albuquerque, New Mexi co850 built homes per yearThe trades work together to build high performa nce

homes at Art istic. Note tha t:

1 . a drywall str ip has been insta lled at the top of

the h allway walls

2. hallway end walls (with bottom plates s pray-

painted orange) have been built a nd set aside.

This cooperation among three trades allows the HVACcontracto r to const ruct and easi ly a i r seal a l l around

the h allway tr unk duct at ground level. He then

insta lls the duct as one as sembly with hangers , and

the 7-foot end wall partit ions are insta lled after t he

HVAC ins ta llation is completed. That 's in tegra ted

design and implementa tion at th e job site (not to

men tion th e efficient wood use s hown her e -- 24 -inch

o.c., in-line framing, single top plate, optimized

header s a nd finger-jointed st uds).

techn ician s — n eed to u n derstan d an d

w ork w ith th e fram in g p lan ju st as m u ch

as th e fram in g crew does.

A s w ith so m an y th in gs in a system as

com plex as a hom e, you m u st alw ays look

at on e facet of efficien cy from th e

persp ective of — overall efficien cy.



“Wast e – t h e Const r uct ion Tai l pi pe”

A t th e en d of th e day n o m atter how efficien t ou r use of w ood,

th ere w ill be som e w aste—off-cuts from both solid-saw n lu m ber

an d sheath in g. E ven for th e m ost efficien tly fram ed bu ildin gs,

w ood w aste w ill be on e of th e largest com pon en ts of th e n ew

con struction w aste stream .

Th ere is som e good n ew s and som e bad n ew s about n ew

con struction w ood w aste. Th e good n ew s is th at it ten ds to be

relatively clean , dry, an d h om ogen eou s (O n th e typical job site

it’s abou t h alf solid-saw n an d h alf sh eet good, u su ally O SB ).

Th ese are u sually good attribu tes for recyclin g. Th e bad n ew s is

th at m arkets th at m igh t m ake g ood u se of th is m aterial—m ulch

for lan dscapers, h og fu el for in du strial boilers an d w ood-fired

electric u tility p lan ts, an d bu lkin g ag en ts for com postin g

op eration s—are gen erally poorly developed.

So, B SC has been w orkin g on tw oaltern atives to lan dfillin g w ood w aste,

both in volvin g keepin g th e m aterial on

th e job site, tu rn in g it in to a resou rce.

• The Si te-Engineered Env ironmen tal

(SE E) s tud

C on sider th e follow in g:

1. A bou t 100 tw o-by-fou rs u sed on a

typical residen tial job site are for

n on -load bearin g in terior

partition s. R egard less of th eresiden tial bu ildin g code u n der

w h ich you are operatin g, u sin g

stru ctu ral-grad e stock in th is

ap plication seriou sly violates

P rin ciple # 2 (see page X X ).

2. Take a look at th e w ood w aste in

you r pile or du m pster — w e w ill

bet th at a lot of th e O SB is in

relatively big pieces from w in dow /

door cu t-ou ts an d roof off-cu ts.

A n d qu ite a b it of th e solid-saw n

w ill be tw o-by-fou r off-cu ts 1 6

in ches or lon ger.

You can see w h ere th is is goin g w ith

th e draw in g below .

Components• 2x4 offcuts• 1/2” OSB or playwood scrap

ripped to 31/2”width• 6# ring-shanked nails

36" min.

length

48" min.length

16" min.length

31/2"width

Equipment for assembly• Tablesaw• Assembly table with chop sa• Nail gun (or hammer)

1/2"max.

5" o.c. max.distance

6" min.distance

1/2"max.


14/31


To date, w e h ave fou n d that if you keep at least on e of th e

O SB 3 1/2-in ch strips cen tered alon g th e len gth of th e stu d

an d at least 36 in ch es in len gth , you w ill get stu ds stiff

en ou gh to satisfactorily fram e in terior n on -load bearin g

w alls. W ith n ails every 4 to 6 in ches an d clu stered arou n d

an y O SB an d tw o-by join t, th e len gth of stu d core scraps does

n ot seem to m atter m u ch. A lth ou gh SE E stu ds are heavier

(an d w ider) th an a regu lar stu d, th ey are alw ays straigh t

an d can be n ailed, drilled , an d tak e fasten ers ju st like a

regu lar stu d. A ll th at from w ood w aste ou t of you r du m pster.

A n d rest assured, th ere is enou gh O SB an d stu d scrap

gen erated in th e U S for every n on -load bearin g stu d to be a

SE E stud.

• On-s ite grinding

If you can grin d you r w ood w aste in to 2 .5-in ch “m in u s”

(m ean in g less th an or equ al to) w ood chips, it m ak es a great

soil erosion con trol m at at job-site en tran ces or berm ed at

th e base of silt fen ces in areas w h ere sign ifican t su rfaceflow is likely. Tu rn s ou t th at th ere are n ow at least tw o

com m ercially available g rin ders ap propriate for residen tial

job sites, grin ders th at h an dle dryw all as w ell as w ood w aste.

A n ew B S C Building America partner is Packer Industries

of A tlan ta, G eorg ia, m an u factu rer of on e of th e low -speed,

m obile g rin ders w ell su ited to th is task . B u ildin g A m erica

produ ction bu ilders in A lbu qu erque, N ew M exico an d

M in n eapolis, M in n esota are fin din g th is approach to d ealin g

w ith th eir w ood an d dryw all w aste com petitive w ith

tradition al disposal. Lim ited research h as show n th e ben ign

con tribu tion of adh esives in E W P s in th is ap plication , an dth ere is on goin g research in G eorgia dou ble-checkin g the

im pact of adh esives w h en con struction w ood w aste

con tain in g

E W Ps is

groun d and

u sed as a

topical

m aterial.

Figure 13 aStuden ts a t the Max

Hayes Vocational High

School in Clevelan d, Ohio

build prototype SEE

studs as par t o f the

process of gaining

builder and building

official appr oval for SEE

stu d use in th e Building

America project,

EcoVillage Clevelan d

townhomes at 5 8 th St .

Figure 1 4aArt istic Homes of

Albuquerque, New

Mexico uses a Packer

750 to grind a ll of its clean wood, car dboar d, and

drywall. They have reduced their constr uction waste by

an es timated 75% t o 80%. Art istic Homes projects that

disposal cost savings will pay for the Packer 7 50 in just

3 years .

Figure 13bStuden ts an d

an ins t ructo r

measure the

deflection

cre ated by loading the 8-foot length of a SEE st ud with a

35 -pound concr ete block. The deflection of the SEE stu d

was compared to that of a stan dard two-by-four t urn ed

sideways . The 200 0 Int er na tiona l Building Code (IBC)

accepts s tuds with th e long dimension parallel to the

wall (sideways ) at 28-inch o.c. for non -load bearin g

in ter ior par t i t ions .

Figure 14bMost of the ground constr uction wood waste at Art istic

Homes is curr ently being gobbled up for use by residents

and other locals for use in lan dscaping.



Roof trusses, wall studs,floor framing, spaced24 in. on center andaligned directly over topof each other (stack framing)

Single top plate

Insulated header supportedon jack stud. Alternatively,header hangers may beused. Eliminate headers innon-bearing walls, such asthose beneath gables.

Place one side ofwindow/door on 24 inchmodule so that existingstuds form one side ofrough opening

Cripple stud necessaryonly for siding or gypsumboard attachment

Single top plate

Point load transferredbetween studs by rimclosure material acting asheader. If rim closurematerial is non-structural,support will be requiredunder point loads. Use solidblocking between joists.

Directionof loadpath

Horizontal member

supported by two-piece stud

Load Bearing Wall

Stack FramingTo gain the most benefit fr om advanced

framing, the concept of “st ack fram ing”

(vertical a lignment of stud, joist, and

roof truss) is utilized. Even balloon

framed walls in two-stor y spaces, such

as this one in a Town and Country home

in Ver non Hills (bottom), can t ake

advanta ge of advanced framing using

the s tack fr aming concept. Note the

header s (actua lly, the lack ther eof), the

location of OSB sh ear panels, and th e

use of insulating sheath ing.

B u ildin g h igh perform an ce hom es is all abou t prov iding construction detai l s th at dem on strate th e bu ildin g

scien ce an d h ow it is applied at th e job site. Th e details show n h ere are tak en from th e bu ildin g scien ce

resou rces, th e E E B A B u ilder G u ides an d th e B SC w eb site resource H ou ses Th at W ork. Th e ph otos sh ow each

detail bein g applied at on e or m ore B u ildin g A m erica project. Th e poin t is -- try th em , th ey w ork.

Each wall should have pairs of cross braces,crossing from top to bottom in opposite directions.

Cross bracing tied into top and bottom plates

Wrapping metal braces over top of top platesand under bottom plates and fastening downinto top plate or up into bottom platesignificantly improves shear resistance

Metal Strap

In an effort t o achieve continuity of insulating

sheath ing ( thermal barr ier and ex ter ior a i r

barr ier), many builders choose to manage shea r

res istan ce by using metal st ra pping. The two

examples here a re Pr airie Crossing in Grays lake,

Illinois (t op) and Vent ur e Inc. in Pont iac,

Michigan (bottom). Note the use of airtight

electrical boxes.


16/31


Header cavity leftopen to be insulatedfrom interior

Single stud

Single top plate

Single headerset towardsoutside of wall,flush withexterior surfaceof stud

Open insulatedsingle header

Stud notched tosupport singleheader

Two stud cornerTwo stud corners allow full insulation

placement in the corner of the fra med wall

and also allow for floating dr ywall corn ers ,

reducing drywall cracking. Traditionally

framed walls create cold uninsu lated corn ers

with potential for drywall cracks. The

photograph at right is from Pra irie Cross ing,

Gra yslake, Illinois.

Connector plate Single top plate

Two stud corner

Alternativecontinuous cornerbead support forgypsum board

Alternative 1x4support forgypsum board

Corner framing

Clip support forgypsum board

Double header withrigid insulation towardsinside preventsgypsum board fromcracking due to headershrinkage

Single top plate

2 x 6

Open insulateddouble header

Insulated headersInsu lated headers can be e i ther manufactu red

or s ite built . The ma nufactur ed type (top right

from Pr air ie Cros sin g, Gr aysla ke, Illinois)

typically comes in long lengths cut on site a s

required. The site built (bottom left from

Artis tic Homes, Albuquerque, New Mexico) or

reces sed header ha s two advant ages: First , the

reces sed space a llows for a dded insulat ion.

Second, it prevents ma chine gun atta chment of

drywall that typically res ults in drywall

cracking.

Sealant

Sealant

Sealant or adhesiveRigid insulation

Rigid insulationfiller Rim joist/band joist

“set-back” on top platethickness of rigidinsulation filler

Connector plate

Single top plate

Top plate splice

Set back rimIn platform construction the ban d joist area

complicates effective ins ulation ins tallation.

To counter the complexity, man y builders

(especially cold climate r egions) choose to u se

an inset r im detail. The inset rim permits

added insulation in a continuous, easily

installed application. The photograph at right

is from Centex Homes, Allegheny Grove,

Minnetonka, Minnesota.

Single top plateThe “st ack fra ming” concept allows for

the u se of single top plate s. The use of

single top plates reduces m ater ial cost

as well as increas es the a mount of wall

cavity for ins ulation insta llation.

Photograph a t r ight fr om Metr o DenverHabitat for Hum an ity, Denver, Colorado.



Rigid insulation

Tape

Prefabricatedinsulated chimney

Prefabricated firestop

Thin profile structuralsheathing asenclosure liner

Sealant or adhesive

Sealant or adhesive

Wood blocking asdraftstop

Sealant or adhesivearound four edges

Sill gasketSealantRigid insulation

Rigid insulation(taped or sealed

joints)

Taped or sealed joints

Sealant, adhesiveor gasket

Adhesive

Sealant, adhesiveor gasket

Fireplace enclosureinsulated to top ofsecond floor ceilingline

Firestop blocking

Support blocking forthin profile structuralsheathing

Sheet metalfirestop

Taped or sealed joints

Thin profilestructuralsheathing

Interior wall intersectingwith exterior wall

Exteriorwall

Solid blockingas draftstop

Plumbing vent or electrical wires

Caulk/seal/foam around all pipes orelectrical wires penetrating into atticspaces or other insulated ceilings

Cut holesufficientlylarger than

pipe to allowinstallation of

sealant

Exterioirwall

Interior plumbingwall Keep plumbing pipes

out of exterior walls

Vent pipemay be

eliminatedwith a

vacuumrelief in

some jurisdictions

Air barrier continuity at fireplaceImproperly installed manufactur ed fireplaces

can dr amat ically challenge the effectiveness of

a home’s air barr ier. In most ca ses, the

sur rounding walls and ceiling that ma ke up the

fireplace enclosure ar e part itions dividing

conditioned s pace and unconditioned s pace,

basica lly an exter ior wall. Yet mos t often, they

do not receive the same attent ion as an

exter ior wall. These walls sh ould not only be

insulated, they should be shea thed and a ir

sealed as par t of air barr ier continuity . The

photograph at right is from Hans Hagen Homes

in Fr idley, Minnes ota.

Air barrier continuity at int erior soffitsAlthough the space within t he s offit is closed

access, this s pace also is par t of the home’s

conditioned s pace. Areas dividing conditione d

and unconditioned s pace should receive proper

detailing to achieve the h ome’s a ir bar rier

continuity. Failure t o maintain air barr ier

continiuty her e wastes en ergy and may allow

warm, moist a ir condensa tion on ducts in air

conditioned houses. Interior solid blocking

draft stops, like the photo at right, are employedat Building America’s Prair ie Cros sin g project,

among other s.

Plumbing penetrationsAny pipe t raveling from conditioned s pace into

unconditioned space sh ould be properly sealed at

the penet ra ting location to maint ain the h ome’sair barr ier continuity . The photogra ph at r ight is

from one of the demonstr ation homes in

Mantachie, Mississippi.


18/31


Caulk/seal/foam all electrical wires penetrating intoattic spaces or insulated ceiling

Exterioir

wall

Interior

wall

Runwiring

alongbottomplate at

exteriorwall*

Caulk/seal/foam all electrical

wires penetrating into exteriorwall

Caulk/seal/ foam all

electricalwires

penetrating

top andbottom

plates of

exteriorwalls

Runwiringalong

side ofstud at

exteriorwall

Electrical penetrationsAny wire or conduit tr aveling from conditioned

space int o unconditioned space should be

properly sealed at the penetr ating location to

mainta in the home’s a ir bar rier continuity. The

photograph at r ight is fr om one of the demonst ra-

tion homes in Manta chie, Missis sippi.

Exterior wall

Interior wall

Air seals (caulking, adhesive,or gasket)

Drywall clips

Drywall clipCeilings, inters ecting partit ions, and corn ers ar e

all opportunities for drywall cracking. Likewise,

these ar eas ar e also opportun ities for the use of dr ywall clips. Dry wall clips cr eate “floatin g”

drywall inter sections, which

allow for the differential

movement of the drywall and its

wood support member. This

reduces the s t ress on the

drywall and hence reduces

dr ywall cracking. And remember,

less wood = m ore insu lation. The

photographs at r ight ar e from

one of the demonstr ation homes

in Mantachie, Mississippi.

Slotted anchorsAs s t r esses ar e appl ied to a t russed

roof’s fr aming sys tem, the bottom

chord will move. Improperly attached

drywall also receives this str ess an d

cra cks. Slotted an chors with floating

drywall corn ers allow the bottom chord

to move independently and s imply bend

the dr ywall with the tr uss’s movement,

not cr ack it . The photogra ph at right is

from The Shores a t Hidden Lake, aPulte Homes, Northern

Californ ia Division develop-

men t in Tra cy, California .

Drywall clips

Slotted anchor atnon-bearing walls

Float drywall at wall corners

Continuous bead of drywalladhesive required here

Clips may also be used

18”

Bead of adhesive Bead of adhesive

18”

Continuous bead of drywalladhesive required here



Case St udi es

In an effort to fu lly dem on strate th e

ad van tag es of u sin g w ood efficien tly, from

optim izin g th e design an d en gin eerin g to

m in im izin g th e w aste stream ,Building

Science Corporation h as prepared a

n u m ber of advan ced fram in g case stu dies.E ach case stu dy dem on strates optim u m

design ch aracteristics as th ey specifically

pertain to a Building America developm ent.

Wood Ef f i c iency and

Bui l d ing Science

U ltim ately, you can on ly u se w ood

efficien tly if it lasts. Th e w ay th at

h eat, m oistu re, an d a ir m ove — or are

restricted from m ovin g — th rou gh

w ood assem blies w ill determ in e

w h eth er th e stru ctu re lasts for ten or

on e h u n dred years. W h erever th e

stru ctu ral fram in g assem bly a lso is a

part of th e structu re’s th erm al

barrier, air barrier, vapor retard er, or

drain ag e plan e, th e fram in g’s lon g-

term serv ice life is a fu n ction of h ow

th e en tire assem bly p erform s w ith

respect to th e flow of h eat, w ater an d

vapor.

T h at’s w h y th e B u ildin g A m erica

ap proach requ ires th at efficien t w ood

u se be accom plished in th e con tex t of

h ow th e bu ildin g en velope p erform s.

A L L of th e m aterials in w all, roof an d

floor assem blies—bu ildin g pap er,

cav ity in su lation , even pain t—m u st be

selected for th eir c o mb in e d therm al

an d m oisture perform ance. H om es

bu ilt w ith ou t th is in teg rated ap proach

th at last say, ju st tw en ty-five yea rs,

w ou ld h ave to be b u ilt fou r tim es

m ore efficien tly th an a h om e th at last

on e h u n dred years, ju st to b reak even

in w ood use!


20/31


Roof framing plan with trusses at 2 4” o.c.Model 227 8

Engl e Homes Case St udy

A Closer Look at Their Ty pical Framing Practices

D en ver is a cold clim ate w ith a reg ion al practice of usin g 2x4

exterior w ood w alls, an d all fram in g m em bers are placed on 16”

cen ters. Th is reg ion al practice is strictly ad h ered to by th e local

bu ildin g com m u n ity, providin g an ideal opportu n ity for an y

bu ilder to take a leadership role w ith adv an ced fram in g an d

advan ced en velope design . Th e E n gle H om es case stu dy

illu strates the resou rce an d en ergy efficien cy gain s associated

w ith ad van ced envelope design an d advan ced fram in g.

House Specif ications

•2 story w ith a 4 2’x30’footprin t

•2,278 total ft2

•8’-1”first floor w all h eigh t

8’-1”secon d floor w all h eigh t

•310 lin ear feet of ex terior w all

Climat e Cons iderat ions

“Cold”clim ate

H eatin g deg ree days 6 ,0 23

H eatin g d esig n tem p . - 3 °F

C oolin g d esig n tem p. 9 3°F

BATH 2

BEDROOM 3

BEDROOM 2

BATH 1

BEDROOM 4

MASTERSUITE

Second floor planModel 227 8

PORCH

LIVING

ENTRY

2 C ARGARAGE

BATH 3

LAUNDRY

NOOK

DINING

KITCHEN FAMILY

First floor planModel 227 8



6

12

12

6

12

5

6

5

12

12

12

6

Right elevationModel 227 8

Rear elevation

Model 227 8

Left elevationModel 227 8

Front elevationModel 227 8

88

12 12

12

12

8

8 8

12

Engl e Homes Model 2278Summar y i nf or mat ion

Wall Area Distribution Sum mary

( s e e p a g e 1 7 )

Wall t ype Opaque Window Cavity

area area are a

2x4(6) 16 24% 16% 60%

2x6 24 O V E 14% 16% 70%

G ross w all area = 2,630 ft2

W in dow area = 408 ft2

Wall Framing Wood Dist ribution Sum mary

( s e e p a g e 1 9 )

Wall t ype Wall s tuds Plat e Cripple s He ade rs

2x4(6) 16 $828 $235 $68 $167

Tot al = $ 1 ,2 9 8

2x6 24 O VE $706 $198 $41 $76

Tot al = $ 1 ,0 2 1

Wall Framing / Performance Summary

2 x4 ( 6 ) 1 6 2 x6 2 4 OVE

713 stu ds 364 stu ds

2,498 board feet 2,003 board feet

$ 1 ,2 9 8 $ 1 ,0 2 1 $2 77 sav i ngs

Insulation

A ssum ed R -13 A ssum ed R -19

A ctual R -9 A ctual R -15

O SB w / housew rap 1”X PS A ctual R -20

$ 2 ,1 1 8 $ 1 ,8 6 2 $25 6 sav i ngs

and 222 %

improvement

Floor Framing / Cost Summary

( s e e p a g e 2 0 )

1 6” floor framing 2 4” floor framing

1,64 0 lin ear feet 1,08 0 lin ear feet$ 2 ,2 9 7 $ 1 ,6 5 1 $64 6 sav i ngs

3/4”floor sheathin g 7/8”floor sh eathin g

(2,250 ft2 of floor sheathin g)

$ 1 ,0 1 4 $ 1 ,4 8 5 $47 2 increase

Net savings = $17 4

Estimate d Cost Saving Summ ary

Advanced wall framing ( OVE) $ 27 7

Advanced floor framing $ 1 7 4

Total e st im ated s av ings $ 4 51


22/31


First floor plan with wall framing elevations• Cu r ren t p rac t i ce i s 2 x 4 (6 ) 1 6 ” o.c .

Second floor plan with wall framing elevations• Cu r ren t p rac t i ce i s 2 x 4 (6 ) 1 6 ” o. c.

2 0 6 8

2 X6

First floor plan with wall framing elevations• Building Science Corporation ana lysis is 2x6 24” o.c.

Second floor plan with wall framing elevations• Building Science Corporation ana lysis is 2x6 24” o.c.

2 0 6 8

2 X6

Bef or e Bef or e

Af t er a f t e r



First floor framing planCurr ent pr actice is 16 ” o.c. for a t otal of 806 linear feet

Second floor framing planCurr ent pr actice is 16 ” o.c. for a t otal of 834 linear feet

First floor framing plan

Building Science Corporation analysis is 24” o.c. for a total of 526 linear feet

Second floor framing planBuilding Science Cor porat ion ana lysis is 24 ” o.c. for a

total of 554 linear feet

Bef or e Bef or e

Af t er a f t e r


24/31


Cent ex Homes Case St udy

Applying Re-Engineering andAdvan ced Framing Concepts to the“Cedarcres t” Mode l

M u ch of M in n esota is considered a very-cold

clim ate, m akin g h eat loss a predom in an t con cern.

R egion al practice is typ ically 2x6 ex terior w ood

w alls an d all fram in g m em bers are placed on 16”

cen ters. A lth ou gh som e bu ilders stray from region al

practice an d p rovide som e aspect of advan ced

fram in g or en velope d esign , it is not as com m on as

on e w ou ld ex pect given th is harsh clim ate. For

C entex H om es, n o floor fram in g com parison w as

n eeded to con vin ce th em of th e ben efits of advan ced

floor fram e d esign . E asily accep ted, th e design an

in stallation flex ibility of open w eb floor trusses at

24”o.c. are appreciated by both C en tex arch itectsan d th eir trade con tractors.


•2 story w ith a 2 8’x36’

footprin t

•2,040 total ft2

•9’-1”first floor w all h eigh t

8’-1”secon d floor w all h eigh t

•256 lin ear feet of ex terior w all


“Very-cold”clim ate


H eatin g d esig n tem p . - 1 6 °F

C oolin g desig n tem p. 9 1°F

First floor plan with wall framing elevationsCurr ent pr actice is 2x6 1 6” o.c.

Bef or e

a f t e r

First floor plan with wall framing elevationsBuilding Science Corporation analysis is 2x6 24” o.c.



Second floor plan with wall framing elevationsBuilding Science Corporation analysis is 2x6 24” o.c.

cent ex Homes“cedar cr est ” modelSummar y i nf or mat ion

Wall Area Distribution Sum mary

Wall type Opaque Window Cavity area

area area ≈ 1 5 0 f t 2

2x6 16 19% 13% 68%

2x6 24 O V E 12% 13% 75%

G ross w all area = 2,178 ft2

W in dow area = 292 ft2

Wall Framing Wood Dist ribution Sum mary

Wa ll t y pe Wa ll s t ud s P la t e Cri pp le s He ad ers To ta l

2 x4 (6 ) 1 6 $ 6 3 3 $ 2 8 2 $ 1 2 5 $ 1 4 6 $ 1 , 1 8 6

2 x4 2 4 OVE $ 4 1 1 $ 1 8 8 $ 9 3 $ 4 9 $ 7 4 1

Savings $ 2 2 2 $ 9 4 $ 3 2 $ 9 7 $ 4 4 5

Wall Framing / Performance Summary

2 x4 ( 6 ) 1 6 2 x6 2 4 OVE

400 stu ds 249 stu ds

2,197 board feet 1,373 board feet

$ 1 ,1 8 6 $ 7 4 1 $4 45 sav i ngs

Insulation

A ssum ed R -19 A ssum ed R -19

A ctual R -13 A ctual R -16

1/2”fiberboard w / 1”X PS A ctual R -20

hou sew rap

$ 2 ,1 7 6 $ 1 ,8 6 3 $31 3 sav i ngs

Second floor plan with wall framing elevationsCurr ent pr actice is 2x6 1 6” o.c.

Bef or e

a f t e r


26/31


Pul t e Homes Case St udy

W h ile th e tw o prior case stu dies w ere based on com pu ter

m odelin g, th is case stu dy w as based on field cou n ts in an actu al

h ou se. Th is hou se is in a predom in an tly coolin g clim ate —

advan ced fram in g saves m on ey in th e fram in g m aterials and

dow n sizin g of air con dition in g equ ipm en t. B ecau se of th eir

success w ith th is an d on e oth er prototype h om e, a n ew P u lteB u ildin g A m erica developm en t of 74 h om es — B eacon P oin t —

h as been re-en gin eered w ith advan ced en velope design an d

fram in g in clu din g th e in n ovative in set shear p an els (see Figure

1 0 ).


Con ditioned floor area 2,495 ft2

Total floor area 2,910 ft2

Typical w all height 9’-11 1/2”

Total con dition ed volu m e 24,850 ft3

Len gth of exterior w all 25 2 lin ear feet

Len gth of in terior w all 34 0 lin ear feet


“M ixed-h u m id”clim ate


H eatin g d esig n tem p . 4 0°F

C oolin g d esig n tem p. 9 7°F

Pu l t e Homes Summar yin f or mat i on

2 x 4 1 6 ” O.C. Wall

8 ’ s tuds Board fe et Cos t

E xterior w all 467 1,634 $866

E xterior plate 95 331 $175

In terior w all 715 2,502 $1,326

In terior plate 126 446 $237

H eader 273 $145

Total wal l f rame cost $ 2 , 7 4 9

2x 6 2 4” Advanced Frame Wal l

8 ’ s tuds Board fe et Cos t

E xterior w all 238 1,312 $695

E xterior plate 63 347 $183

In terior w all 279 977 $518

In terior plate 85 298 $158

H eader 148 $ 78

Total wal l f rame cost $ 1 , 6 3 2

Wood Frame Wall Sum mary

2 x4 2 x6 Reduced by

8’stu ds 1,403 665 (-735/-52% )

B oard feet 5 ,1 86 3 ,0 82 (-2 ,1 04 /-4 0% )

Cost $ 2 ,7 49 $ 1,6 3 2 (-$1,117 / -4 0%)

Builder initial cost s avings

≈ $1 ,117 ( f raming)

Homeowner s aves

≈ $ 293 (an nual ly)

Environmental impact

≈ 40% less energy

≈ 2,104 boar d feet of lumber or 73 8 — 8’-0” studs

≈ 1,490 lbs. carbon emiss ions



Ext erior Wall Break dow n

Gr oss a r ea of wa ll 2 ,0 9 8 ft 2

Gr oss a r ea of window/ door 3 2 2 ft 2 1 5 %

Op aqu e ar e a o f 2 x 4 1 6 ” o. c. fr a m e 5 0 4 f t2 2 4 %

Op aqu e ar e a o f 2 x 6 2 4 ” o. c. fr a m e 2 5 4 f t2 1 2 %

Ca vit y a r ea of 2 x 4 1 6 ” o. c. fr a m e 1 , 2 7 1 ft 2 6 1 %

Ca vit y a r ea of 2 x 6 2 4 ” o. c. fr a m e 1 , 5 2 2 ft2

7 3 %

R-Value Truths

2x4 16” o.c. walls

• Assu m ed cen ter of wall 1 3 .0

• Wh ole wa ll R-va lu e 9 .4 7 2 %


• Assu m ed cen ter of wall 1 9 .0

• Wh ole wa ll R-va lu e 1 5 .2 8 0 %

Sheath ing Costs

OSB/ Tyvek $ 6 4 9 .4 8 R-0 .0 6

1 ” EPS $ 4 4 0 .4 8 R-4

1 ” XPS $ 6 9 2 .1 8 R-5

1 ” polyisocyanu r a te $ 7 9 7 .0 5 R-7

Energy Loads


• Heat load 4 5 .2 kBtu h

• Coolin g load 4 5 .6 kBtu h

2x6 24” o.c. walls• Heat load 2 8 .0 kBtu h (-3 8 %)

• Co oli n g l oa d (d own s iz ed a / c ) 2 6 .0 k Bt u h (-4 3 %)

Energy Costs


• Heat in g $ 3 3 2 / year $ 2 8 / m on th

• Coolin g $ 6 7 1 / year $ 5 6 / m on th

• Total annual cost $ 1 , 0 0 3


• Heat load $ 2 3 1 / year $ 1 9 / m on th

• Coolin g load $ 4 7 9 / year $ 4 0 / mon th

• Total annual cost $ 7 1 0 ( -$293 / -30%)

The Shores at Hidden LakeTracy, Californi a

2 prototypes bui l t / 74planned

A Not e on Real

wal l r - val u es

M ore often th an n ot, th e th erm al

perform an ce o f bu ilt w alls is

in correctly ch aracterized by th e

cen ter-of-cavity R -valu e of th e w all’s

th erm al in su lation . B u ilders an d

h om e bu yers shou ld b e lookin g at th e

whole-wall R -valu e — th at’s the

th erm al con du ctivity perform an ce of

th e cavity in su lation ,and th e

fram in g,and th e w in dow s, and th e

do ors. W h en both th e h om e’s design

an d th e fram in g layou t are optim ized

for fu n ction an d perform an ce, th e

differen ce betw een th e assum ed

cen ter-of-cav ity w all R -va lu e an d th e

w h ole w all R -valu e can be su bstan tial

(see th e R -Va lu e T ru th s in th e P u lte

case stu dy ).

•W hole w all R -valu e (averag e across w all)

W in dow = R -3

D oor = R -2

2x4 stu d = R -4.4

2x6 stu d = R -6.8

Insulation = R -11 to R -19

(depen din g)


28/31


Summar y

From design to du m pster, residen tial con struction abou n ds w ith opportu n ities to m ake

m ore efficien t u se of ou r w ood resources an d produ cts. A n d m ost of th e opp ortu n ities are

cost-com petitive an d th en som e, as w ell as deliverin g a h igh er perform an ce hom e. Few

system s in h om e bu ildin g offer such clear w in -w in prop osition s as efficien t w ood u se.

Th e han dy ch ecklist below sum m arizes th e opp ortu n ities covered in th is paper, each on e

sup ported by Building America ex perien ce w ith som e of th e n ation ’s lead in g p rodu ction

bu ilders. To save w ood fiber, prin t u p cop ies of ju st th is list for you r com pan y an d

con tractors!

1. A lw ays m ake u p d etailed fram in g p lan s, to in form th e design process an d to

in form you r fram in g crew an d th eir use of w ood on th e job site.

2. U se en gin eered w ood an d certified su stain ably h arvested w ood produ cts

w h en ever possible.

3. H on e dow n you r w aste factor in you r lu m ber take-off, an d treat lu m ber deliveries

as produ ct—stick an d cover th e load s w h en th ey are delivered.

4. U se structu ral grade m aterials to th eir fu ll approved cap acity.

5. D on ’t u se structu ral grad e m aterials in n on -stru ctu ral ap plication s if other

m aterials can accom plish th e requ ired fu n ction (s).

6. E m ploy w ood w aste in on -site app lication s, such as SE E stu ds an d erosion con trol

m aterial.



Hidden SpringsDevelopment Corp.Hidden SpringsB oise, Ida h o

Artistic HomesEl Rancho GrandeA lbuquerque, N ew M exico

Homes

Ranch Parkland Placeon , exas

Pulte HomesOakbrooke Patio HomesM in n eapo lis, M in n esota

Pulte HomesThe Shores at Hidden Lake

Tracy, C aliforn ia Pulte HomesDevelopmentac son v e, or a

f

Bui l d ing Sc ience Consor t iumBui l d ing Amer icapar t i al l i st of pr oj ectLocat ions

Th rough th e B u ildin g A m erica program , B u ildin g

Scien ce C orporation w as able to p rovide design

assistan ce on w ood efficien cy to produ ction bu ilders

from across th e U n ited S tates.

U.S. Department of Energy

P r o g r a m P a r t n e r


30/31


Ack nowl edgment s

Th is w ork w as supp orted b y th e U .S. D epartm en t of E n ergy, O ffice of B u ildin g

Techn ologies, State an d C om m u n ity P rogram s, B u ildin g A m erica Program , G eorge Jam es,

P rogram M an ager. E ditors in clu de N ath an Yost, M .D ., Joseph Lstibu rek, P h .D ., P.E n g. an d

B etsy P ettit, A IA .

Resour ces EEBA Builder Guides, Joseph Lstiburek, 2000. Energy and Environmental Building

Association. https://www.eeba.org/mall/builder_guides.asp

Efficient Wood Use in Residential Construction: A Practical Guide to Saving Wood,

Money, and Forests, Ann Edminster and Sammi Yassa, 1998. Natural Resources

Defense Council. http://www.nrdc.org/publications/default.asp

Residential Construction Waste Management: A Builder’s Field Guide, Peter Yost

and Eric Lund, 1997. NAHB Research Center.http://www.toolbase.org/tertiaryT.asp?TrackID=&CategoryID=34&DocumentID=2629

Cost Effective Home Building: A Design and Construction Handbook , Tim Waite,

1996. NAHB Research Center. http://www.toolbase.org/

tertiaryT.asp?TrackID=&DocumentID=2584&CategoryID=917

Houses That Work (web-based freely downloadable documents and drawings),

Nathan Yost and Joseph Lstiburek, 2001. Building Science Corporation. http://

www.buildingscience.com/housesthatwork/default.htm


31/31

Building Science Research Report 2002 - 01

About this Report

This report was prepared for the US Department of Energy’s Building America Program. The report is freely available to the public at www.buildingamerica.gov.

Direct all correspondence to: Building Science Corporation, 70 Main Street, Westford, MA 01886

Limits of Liability and Disclaimer of Warranty:

Building Science documents are intended for professionals. The author and the publisher of this article have used theirbest efforts to provide accurate and authoritative information in regard to the subject matter covered. The author andpublisher make no warranty of any kind, expressed or implied, with regard to the information contained in this article.

The information presented in this article must be used with care by professionals who understand the implications of what they are doing. If professional advice or other expert assistance is required, the services of a competentprofessional shall be sought. The author and publisher shall not be liable in the event of incidental or consequential

damages in connection with, or arising from, the use of the information contained within this Building Science document.

Documents

Advanced Framing Wood Efficiency