SMACNA Architectural Sheet Metal Manual

Peyton CollieProject Manager Technical Resources

SMACNA

Architectural Sheet Metal Manual 7th Edition

Completed update in early 2012 540 Pages (46 added) 188 CAD Drawings (29 new, many revised)

Drawings can be purchased separately 100s of editorial changes Added soldering and sealant guidance and

fascia and coping wind test to appendix

SMACNAs Manual Development Process And Procedures

Expertise is provided by a task force of SMACNA members with subject-specific experience

The task force guides SMACNAs technical staff in the development of content

Near-final drafts are distributed to local chapters for review by local, experienced contractors

Posted on SMACNA's website for 60-day public review

Some manuals go through the ANSI process using an additional canvass method of review

Technical Inquiries provide a source of feedback

Technical Inquiries

Customer technical support service Interpret SMACNA standards for:

Code officials Designers Members

Benefits of the service to SMACNA: Source of user feedback for future manual

upgrades Early indication of construction trends

Sheet Metal As An Architectural Element

Basic building material, long history of use Metals can be mixed to create totally unique

metalsand shapesfor unique buildings Metal roofs are enjoying a resurgence of use

notably, cool roofs Lowest-cost choice based on life cycle costing Many important metal elements are often

invisibleFlashing!

Benefits Of Sheet Metal Properly designed and professionally constructed

and installed by experienced contractors sheet metal elements can last for centuries

Sheet metal fits all green building materials measures, especially recycled content Recycled content: steel = 25%; copper = 43%; lead =

55%; stainless steel = 50% Energy efficiency per Florida Solar Research = light-

colored metal roofs VERY energy efficient Light weight and versatile

Soldered sheet metal joints do not require continuous maintenanceunlike ALL sealants

History Of Architectural Metals

First used by the ship building industrylead used in the 1500s with rolled copper use starting in late 1600s

New York City Hall used copper for roofing circa 1764 A copper roof was used on the rebuilt Old Senate

Chamber in 1819; replaced in a 1900 renovation The slate roof on the White House was replaced with

sheet iron in 1804 The copper roof on the Old Church of Christ in Philly

lasted from the 1830s to 1967 when the substrate failed Early metal roofs were batten-style or flat-seamed until

rolled tin production became common after the WBTS when standing seam came to general use

ASMM Contents Roof Drainage Design & Systems Gravel-Stop Fascia >> Roof Edging Copings Flashing Building Expansion Metal Roofs Wall Systems Louvers & Screens Miscellaneous Metal Structures Historical Restoration >> Much New Material Appendices >> Much New Commentary

Roof Drainage Design Roof Area Rainfall Intensity Metal Selection Gutter Type & Sizing Downspout Type & Sizing

Conservative compared to codes Expansion Allowances Fastening Method Selection Flashing Requirements

FIGURE 1-2 RECTANGULAR GUTTER STYLES10

11

Built-in Gutters

Subject of many Technical Inquiries Poses greatest risk of water intrusion Soldered or welded joints only Use high-quality membrane underneath Specific shapes address water freezing Attention to expansion allowances No single downspouts per roof section

FIGURE 1-5 ALLOWANCES FOR GUTTER EXPANSION13

Fastening Method Selection

Appendix for fasteners and soldering Screws best, SS best for treated wood

Commentary and illustrations throughout detailing clips, cleats, reglets

Solder old fashioned TI?s Solder permanent, sealants continuous

maintenance

Flashing Recommendations

Flashing section second largest in manual++ Incorrectly installed/designed flashing and

poor craftsmanship identified as major culprit at mold conferences Especially around windows! Roof edges and bottom of wall also problem areas

Techniques in manual superior to the caulk and pray approach Inset reglets, embedded metal, counter flashing, use

of clips and cleats, etc.

Gravel-Stop Fascia (Edge)

Chapter covers a multitude of fascia finishing methods for flat roof systems

Water should NOT be allowed to flow over the edge of built-up roofs!

Be careful with ladders and never step on the top (peak) of fascia edging

Another reason for controlled access

FIGURE 2-6 CAP FASCIA - INSTALLATION17

Copings The horizontal top surface most vulnerable

point for water to enter an exterior wall Water entering a wall travels horizonally

Copings provide a permanent water stop and reduce wall-related maintenance

Metal copings provide an attractive, finished appearance

Affected by new IBC wind uplift requirements

20

LOCKS AND SEAMS 22

Flashing Possibly the most important chapter! Time-tested (old-fashioned) methods to prevent

moisture intrusion Key component for the protection of the

structural elements and interior Use and importance of flashing was specifically

mentioned by several speakers at NIBS-BEC mold conferences

Soldered metal joints = no/low maintenance

FIGURE 4-4 COUNTER FLASHING SYSTEMS - INSTALLATION24

Building Expansion

Expansion and contraction = important design factor for larger structures/additions

Movement accommodated by specially-designed interlocking expansion joints

Proper width of expansion joints based on the total amount of expansion driven movement

FIGURE 5-3 BUILDING EXPANSION JOINTS ROOF AT GRAVEL STOP

26

Metal Roofing Early consultation with experienced sheet

metal contractor highly recommended Two types of metal roofs:

Non-structural requires continuous support Structural spans use intermittent supports

Compatibility of all materials and galvanic reactions need to be understood

Support/underlayment design critical Continuous enclosure barrier new challenge

in newer building codes & 90.1 NIBS BEC

FIGURE 6-5 STANDING SEAM ROOFS28

Standing Seam Roofs

Recommended for slopes of 1 in./ft or greatersealants not typically used on the vertical seam greater than 3 in./ft

Designers should consult local contractors for recommendations based on local conditions and experience

Evidence of declining uplift resistance as seam height increases

FIGURE 6-8 BATTEN SEAM ROOFS30

31

Batten Seam Roofs Recommended for slopes of 3 in./ft or greater Copper or aluminum metal Prominent ribs amplify the visual impact of roof Offers architects the widest range of individual

expression Size & shape of battens Intersecting battens at various angles Use in combination with other roof types and styles

33

FIGURE 6-11 BERMUDA TYPE ROOFS

34

Bermuda Roofs

Simulates the thick limestone shingles used on roofs in Bermuda

Used on contemporary designed structures Promotes a long, low look to the structure Can be used in conjunction with battens to

define separate planes Original function?

FIGURE 6-3 FLAT SEAM ROOFS36

Flat Seam Roofs Typically made from 20 x 28 sheets,

geometry is important Copper or dead soft stainless steel is

recommended Lock and seal all joints, solder joints on

slopes less than 3:12 Tapered-batten expansion joints required

on flat seam sections exceeding 30 feet

Appendices Metal Applications and Specifications Galvanic Corrosion Sheet Metal Roof Test Report Custom Fabricated Metal Roof Specs Moisture and maintenance of envelopes Fasteners Soldering Fascia and Coping Wind Tests

Galvanic Corrosion

Not well understood by many designers Proximity of metals in chart Passive SS simply means chemically

cleaned (changes characteristics) Contact not required, runoff can cause

corrosion Beware of HVAC condensate via copper

pipes to galvanized gutter

Galvanic Scale ANODIC/CORRODED END/LEAST NOBLE Zinc Aluminum Galvanized Steel Cadmium Mild Steel, Wrought Iron Cast Iron Stainless Steel, types 304 and 316 (active)* Leadtin Solder Lead Brass, Bronze Copper Stainless Steel, types 304 and 316 (passive) CATHODIC/PROTECTED END/MOST NOBLE*Chemically cleaned usually with acidic solution

Sheet Metal Roof Test

UL Standard 580/Factory Mutual

Static Water Penetration

Dynamic Water Penetration

Structural Load

Deflection

Not Wind Resistant

IBC Section 1504.5

Edge securement for low-slope roofs. Low-slope membrane roof system metal edge securement, except gutters, shall be designed and installed for wind loads in accordance with Chapter 16 and tested for resistance in accordance with ANSI/SPRI ES-1, except the basic wind speed shall be determined from Figure 1609.

SPRI STANDARD ES-1

Edge membrane retention SPRI Test RE-1 Force required to separate membrane from

edge device, strength of membrane key Edge flashings SPRI Test RE-2

Force required to pull edge device off wall Copings SPRI Test RE-3

Force required to lift coping off wall

How Compliance is Met

Designer calculates and specifies minimum wind pressure (uplift)

Metal element must be manufactured or custom fabricated to tested design

Metal element must be installed using methods according to tested design

Metal element is inspected as fabricated and installed as per a tested design

Fascia Pulloff Testing (Wind Uplift)

Pull Numbers

ASTM Standard Language

In applying the results of tests by this test method, note that the performance of a wall or its components, or both, may be a function of fabrication, installation, and adjustment.

SPRI Std Does NOT Require Third party certification of construction

This provides no assurance correct element was installed or installed correctly

Any type of stamp indicating compliance on compliant elements This was discussed at length during the

development of the SPRI standard and determined to have no merit because it provides false sense of compliance

Contractors Qualification Checklist

Jointly developed by AIA & SMACNA Design limited only by imagination, not contractor skills Positive impacts on project completion schedule Ensures proper installation, increases architects options

for future creativity Qualifies contractor based proven experience record Assures two most important characteristics of

architectural elementsaesthetics & water tightness

QuestionsCommentsSuggestions