Upload
blaze-sherman
View
215
Download
1
Embed Size (px)
Citation preview
2
Links for Chapter 26
Floor Construction
Wall Construction
Roof Construction
Related Web Sites
Environmental Design
3
Conventional Floor Framing
• Floor joists range from 2” X 6” to 2” X 14” and spaced at 12”, 16”, or 24”
• Mudsill rests on the masonry foundation– Provides a base for all framing
– Attached to foundation with anchor bolts
– Either 3/4” or 5/8” in diameter
4
Conventional Floor Framing
FLOOR JOIST
FLOOR JOIST
SILL
MUD SILL &ANCHOR BOLTS
STEM WALL
FOOTING
FOOTING
STUDS
STUDS
FLOOR SHEATHING
RIM JOIST
FLOOR SHEATHING
CRAWL SPACE
WALL SHEATHING
SHEATHING
SOLID BLOCK
GIRDERPOST
CONC. PIER
GUSSET
SILL
SOLID BLOCK
MUD SILL &
STEM WALL
ANCHOR BOLTS
5
Conventional Floor Framing
• Girder (beam) is used to support the floor– A flitch beam consists of steel plates bolted
between wood members
– Glu-lam beams are laminated with sawn lumber and more structurally stable
– Engineered wood girders consists of laminated veneer strips glued together
6
Conventional Floor Framing
• Girder (beam) is used to support the floor– Steel beams are used for long spans and do
not shrink or expand
– A post is used to support beams and are 4” X 4” or 6” X 6” depending on beam width
– Steel posts do not draw moisture and remain a more true size
7
Conventional Floor Framing
FLOORJOIST
RIM JOIST ORSOLID BLOCK
SHEATHING
SILL
SOLID BLOCKOVER BEARINGWALL
DOUBLE TOP PLATE
STUDS
STUDS
CANTILEVER
8
Conventional Floor Framing
• Joists support the subfloor– Joists that span past a girder are cantilevered
– Joists shaped as an “I” are called trusses
– Laminated veneer lumber is used for heavy loads with single or multi-spans
– Engineered joists support larger loads with less material
9
Conventional Floor Framing
FLOORJOIST
RIM JOIST ORSOLID BLOCK
SHEATHING
SILL
SOLID BLOCKOVER BEARINGWALL
DOUBLE TOP PLATE
STUDS
STUDS
CANTILEVER
11
Floor Bracing
• Joists will tend to roll as loads are applied
• Blocking is used at the center of the joist span to help transfer lateral loads
• Sheathing is placed over the joists to form the subfloor– Face grain should be perpendicular to the
floor joists
13
Post-and-Beam Construction
• Girders are supported on a post and concrete pier– Usually 4” X 6”
– Spaced at 48” o.c.
– Flooring is 2 X 6 or 2 X 8 tongue and groove boards or 1 3/32” plywood
14
Post-and-Beam Construction
MUD SILL &ANCHOR BOLTS
STEM WALLFOOTING
FLOOR DECKING
SILL
GIRDERCONC. PIER
GUSSET
CRAWL SPACE
POST &
SILL
STUDS
GIRDER
FLOOR DECKING
CONC. PIER
POST &GUSSET
15
Framed Wall Construction
• Bearing walls support the weight of the roof or other floors– Extra support is required under it
• Nonbearing walls have no structural purposes– Sometimes called partitions
– Can be removed without causing damage
17
Framed Wall Construction
• Sole plate is the bottom plate and disperses the wall load to the floor system
• Studs are vertical framing members to transfer load from top of wall to floor system
• Top plates are used to hold the wall together– Two are required on bearing walls and must
lap by at least 48”
18
Framed Wall Construction
• Sheathing is used as an insulator against weather
• Double-wall construction is when sheathing is applied to an exterior wall
• Single-wall construction is when a vapor barrier and no sheathing is used on an outside wall
19
Framed Wall Construction
• Sheathing helps walls not to twist or rack
• Shear panel resists these forces
• Let-in braces stiffen stud walls
STUDS TEND TO SHIFTOR RACK WHENPRESSURE IS APPLIEDTO THEIR WIDE SURFACE
FORCE(WIND ORSEISMIC)
STUDS INNORMALPOSITION
20
Framed Wall Construction
• Header is an opening above a door or window
• Trimmers support headers
• Subsill is on the bottom of a window
FLOOR SHEATHING
RIM JOIST
TOP PLATES
CRIPPLE (JACK)STUDS
HEADERTRIMMER
KING STUD
SUBSILL
JACK STUDS
SOLE PLATE
FLOOR SHEATHING
RIM JOIST
TOP PLATES
HEADERROUGHOPENING
CRIPPLE (JACK) STUDS
21
Roof Construction
• Eave on the roof extends beyond the walls
• Cornice is the covering on the eaves
• Fascia is trim placed at the end of the rafters
• Roof sheathing covers structural members
• Skip sheathing is used with either tile or shakes
22
Roof Construction
BAFFLEAT VENT
SOLID BLOCK-OMITEVERY THIRD FORSCREENED VENT
FASCIA
RAFTER
INSULATION
BAFFLEBTWN EA.RAFT
RAFTER
2 x 4 NAILER
SCREENED VENT
RAFTER
FASCIA
RAFTER/CEILING
NOTCH RAFTERTAIL TO MATCHFASCIA
2" AIR SPACEABOVE INSULATION
3-1" SCREENEDVENTS AT EACH
SOLID BLOCKWITH 2" AIRSPACE ABOVE
G.I. FLASHING
FASCIA
SCREENED VENT
NOTCH RAFTER TAIL
JOIST
RAFTER SPACE
1/2" "CCX" EXT. PLY
1/2" "CCX" EXT. PLYOR 1X6 T&G TYP.
23
Roof Construction
• Finished roofing is the weather protection system
• Pitch describes the slope of the roof– Rise is the vertical distance of the slope– Run is the horizontal distance of the slope
• Span is the horizontal measurement between inside edges of supporting walls
25
Roof Construction
• Conventional framing involves the use of wood members placed in a repetitive fashion
• Ridge board is the horizontal member at the ridge and runs perpendicular to the rafters
• Rafters are the sloping members used to support roof sheathing and finished roofing
27
Roof Construction
• Common rafter spans and supports the roof loads from ridge to top plate
• Bird’s mouth is the notch cut in rafter where the rafter intersects a beam or bearing wall
• Hip rafter is used on the slopes of the hip• Valley rafter is used on the slopes of the
valley
28
Roof Construction
COMMON RAFTERS
HIP JACK RAFTERS
HIPS
RIDGE
VALLEY RAFTERS
TOP PLATES
HIP
VALLEY
29
Roof Construction
• Ceiling joists span between top plates and bearing walls
• Ridge braces are used to support downward action of the ridge board
• Ridge beam supports the upper end of the rafter/ceiling joists
30
Roof Construction
RIDGE
COLLAR TIE @ 48" O.C.
CONTINUOUS PURLIN
PURLIN BLOCK
PURLIN BRACEAT 48" O.C.
CEILING JOIST
45Þ MAX.
31
Truss Roof Construction• Truss is a component used to span large
distances without intermediate supports• Top chord supports the roof sheathing• Bottom chord resists outward thrust of the top
chord and supports• Webs span between top and bottom chords• Ridge blocks provide nailing surface for roof
sheathing
32
Truss Roof ConstructionTOP CHORD
BOTTOM CHORD
WEBS
TRUSSCONNECTORS
CLEAR SPAN (INSIDE TO INSIDE)
TOTAL SPAN (OUTSIDE TO OUTSIDE)
TRUSSCLIP
RIDGE BOARD
RAFTERS
DOUBLE TRIMMER
DOUBLE HEADER
ISOMETRIC
PLAN
RAFTERS
DOUBLE TRIMMER
DOUBLE HEADER
33
Truss Roof Construction
• Cantilevered truss is when the truss extends beyond the support
• Hip truss is used to form hip roofs• Vaulted or scissors truss have inclined bottom
chords• Metal hangers keep floor, ceiling, and roof
members from separating
34
Truss Roof Construction
STANDARD GABLE END
CANTILEVERED STUB
MONOHIP
SCISSORVAULTED
ATTICDUAL PITCH
GAMBRELBROKENPITCH
HEADER
STANDARD GABLE END
CANTILEVERED STUB
MONOHIP
SCISSORVAULTED
ATTICDUAL PITCH
GAMBRELBROKENPITCH
HEADER
35
Truss Roof Construction
STD. TRUSSES
GIRDER TRUSS
3 PANEL WINDOWSKYWALL.
HEADERTRUSS
6'-0" TYPICALVERIFY EXACT SIZEW/ MANUFACTURER.
FRAME AREA OVER RAFTERS @ 24" O.C.
36
Environmental Design
• It is important to be familiar with chemicals that are commonly found in the home– Formaldehyde is a colorless gas found in
most resin-based construction products
– It can cause irritation to nose, throat, and eyes and cause headaches, coughing, and fatigue
37
Environmental Design
• Optional material can be used that does not contain harmful chemicals– Grass-based boards can be used for
sheathing
– Low-toxic products that repel moisture
– All natural carpets reduce allergy reactions
38
Environmental Design
• Gas and oil heaters are more efficient, they do produce toxic chemicals and reduce the quantity of natural resources
• Electric heaters are nontoxic yet are more expensive and less efficient
39
Related Web Sites• American Lumber Standards Commission,
Inc. - www.alsc.com• Gypsum Association - www.gypsum.org• The Masonry Society - www.masonrysociety
.org• Wood Truss Council of America- www.
woodtruss.com