Asphalt Shingle Roof Installation Procedures
Best Roofing Practices Guide

...

Installation Temperature Requirements for Asphalt Shingle Roofs

Ideally, shingles should be installed at temperatures ranging from 40°F to 85°F. Below 40°F, shingles are brittle and crack easily when hammered or bent.

Above 85°F, it is easy to tear the shingles or mar the granular coating. In hot temperatures, roofers often start very early in the morning and break at midday. In cold temperatures, it is best to store the shingles in a heated enclosure until they are installed.

Details about shingle temperatures in manufacture and on-roof are

at ASPHALT SHINGLE TEMPERATURES

[Click to enlarge any image]

Adapted/paraphrased with permission from Best Practices Guide to Residential Construction (Steve Bliss, J Wiley & Sons),

chapter on BEST ROOFING PRACTICES

...

Manual Sealing Requirements for Asphalt Shingle Roofs

Details about the sealing recommendations from asphalt shingle roofing experts are at WIND DAMAGE to ROOFS
and

at ASPHALT SHINGLE CELLOPHANE STRIP REMOVAL we include an exhaustive review of the argument around whether or not one should remove the cellophane strips from the back of asphalt roof shingles before they are installed [basically, no, provided they are secure and in place].

Here is what the GAF Materials Corporation, Grand Timberline™ Premium Architectural Shingle Application Instructions say about the glue strips and cellophane. You'll note that we are to leave the cellophane in place, but if site conditions (high wind) require immediate shingle sealing, an extra step, using additional shingle tab adhesive, is permitted.

WIND RESISTANCE/HAND SEALING: These shingles have a special thermal sealant that firmly bonds the shingles together after application when exposed to sun and warm temperatures. Shingles installed in Fall or Winter may not seal until the following Spring.

If shingles are damaged by winds before sealing or are not exposed to adequate surface temperatures, or if the self sealant gets dirty, the shingles may never seal. Failure to seal under these circumstances results from the nature of self-sealing shingles and is not a manufacturing defect.

To insure immediate sealing, apply 4 quarter-sized dabs of shingle tab adhesive on the back of the shingle 1" (25mm) and 13" (330mm) in from each side and 1" (25mm) up from bottom of the shingle. Press shingle firmly into the adhesive.

For maximum wind resistance along rakes, cement shingles to underlayment and each other in a 4" (102mm) width of asphalt plastic roof cement.

NOTE: Excess tab adhesive can cause blistering of the shingle.

[The company is referring to the use of additional roof shingle adhesive, not the factory-applied glue strip. Also

see BLISTERS on ASPHALT SHINGLES - Ed.]

The film strips on the back of each shingle are to prevent sticking together of the shingles while in the bundle and to keep dirt and debris out of the adhesive material so that after installation the adhesive will work. Their removal is NOT required during application.

In cold climates, the asphalt shingle sealant strip may not set up properly and may require manual sealing.

For three-tab shingles, place two quarter-size spots of plastic roof cement under the lower corners of each tab (as shown in Figure 2-7).

With laminated shingles, place four to six quarter-sized dots, spaced evenly, about one inch above the bottom of the overlapping shingle.

Our page top photo shows the standard sealant strips [image] found on asphalt shingles, in this case a GAF® product we photographed at a Home Depot® store.

Details about the sealing recommendations from asphalt shingle roofing experts are

at WIND DAMAGE to ROOFS.

Starter Course Requirements for Asphalt Shingle Roofs

After the underlayment and drip edge are installed, a starter course of asphalt shingles, with the tabs removed, is nailed along the eaves so its sealant strip seals down the first course.

Illustrations© adapted from GAF Timberline® Application instructions, cited in detail below. [Click to enlarge any image]

The recommended starter shingle course details vary among manufacturers but typically would be placed as follows:

Either use starter-strips provided by the manufacturer, OR if you are not using a precut shingle starter strip, trim 6 to 7" of the tabs or lower portion of all of your starter course shingles, then install the remaining solid asphalt strips along the eaves.

That is going to yield a starter strip that is no less than 6" in width.

Watch out: don't forget as well to trim 6" off of the end of the first starter strip - shown at the left end of the first starter strip in our image above. This will assure that the butt joints of the starter strips do not end up right under the butt joints of the first full shingle course.

The starter strip is placed to lap over the eave and rake edges (and drip edge that should have already been placed) by 1/4" to 3/4". Don't overlap more than that or the unsupported shingle edges are likely to curl and break over time.

Nail the starter strips up 3" to 4" (76mm to 102mm) from the roof edges or eaves. No less than 4 nails are used. If using three-tab open-cut asphalt shingles the nails need to be placed so that they will not be exposed by the cut-outs between shingle tabs.

The first full-shingle course is then laid over the starter course with the full shingle lower edge flush with the edge of the starter course.

Our illustration of the starter course and first course of roof shingles shown here is excerpted from

TIMBERLINE® APPLICATION INSTRUCTIONS [PDF] (2007) GAF-Elk Corporation, Technical Services: Tel: 1-800-ROOF-411 or Website: www.gaf.com retrieved 2018/08/08, original source: http://esgreenville.com/wp-content/uploads/2011/07/timberlineinstallation.pdf

Watch out: Starter shingle courses for re-roof jobs are different, typically cut 5" rather than 6" as we explain

at ASPHALT SHINGLE RE-ROOF GUIDE.

Offsets Between Shingle Courses, Requirements for Asphalt Shingle Roofs

Successive courses are typically offset 6 inches (half a tab horizontally) on a 36-inch shingle in a stepped fashion, making cutouts align every other course and butt joints align every seventh course (Figure 2-8).

For a more random pattern where cutouts align only every eighth course, offset shingles only five inches.

Both of these patterns effectively resist leakage, but the 5-inch offset may provide longer wear since water will not be channeled down the cutouts thereby eroding the stone topping.

Shingle Laddering is Not Recommended

As we discuss in detail

at LADDERING vs STAIR STEPPING SHINGLES,

for ease of installation some roofers install shingles straight up the roof in sets of one or two shingles wide, staggering shingles 6 inches or 18 inches back and forth as shown in our photo and as illustrated in Steve Bliss's Figure 2-9 below.

Since this lines up butt joints every other course, this is considered a less watertight roof and may leak under extreme situations, such as windblown rain on a low pitch.

Ladder style application of asphalt roof shingles is not recommended by any roofing manufacturers. Manufacturers also claim that shingle color patterns may create splotches or stripes if laid this way.

Racking is another form of (or a synonym for) laddering in which shingles are laid straight up the roof in columns just one shingle wide.

DO NOT lay shingles straight up the roof (racking) since this procedure can cause an incorrect color blend on the roof and may damage the shingles - Timberline GAF instructions, Op. Cit. We add that it also increases the chances of roof leaks.

...

Fastening (Nailing) Requirements for Asphalt Shingle Roofs

The preferred fastener is galvanized roofing nails with a minimum 12-gauge shank and head diameter of at least 3/8 inch.

Although staples are allowed in some jurisdictions, they do not provide the same holding power.

[Click to enlarge any image]

Both nails and staples should be long enough to penetrate the roof sheathing by 3/4 inch or penetrate 1/4 inch through the sheathing if it is less than 3/4 inch thick.

Fasteners should be driven straight and flush with the shingle surface (Figure 2-10 above).

Overdriven nails or staples can cut into the shingle or crack it in cold weather.

Roofing nails driven through the roof material placed on 1/2" (nominal) thick plywood roof deck must be long enough that the tip of the roofing shingle nail penetrates beyond the underside of the roof deck by at least 1/4". This assures that there will be sufficient holding power of the roof deck around the full-diameter shank of the roofing nail.

Nails can penetrate more that that required 1/4" minimum but not less, unless the roof decking is a thicker material.

When using shingle staples rather than roofing nails, the same 1/4" extension of the staple tips beyond the underside of the roof deck is also quired .

• Dixon, Craig Robert, THE WIND RESISTANCE OF ASPHALT ROOFING SHINGLES, [PDF] (2013 Dissertation thesis), University of Florida, retrieved 2017/09/27, original source http://ufdc.ufl.edu/UFE0046235/00001, Excerpt:
  
  Florida Building Code (2010), Building Commission 2010) requires that fasteners should consist of:
  
  Galvanized steel, aluminum or copper roofing nails, minimum 12 gage [0.105 in (3 mm)] shank with minimum 3/8 in (10 mm) diameter head, ASTM F 1667, of a length to penetrate through the roofing materials and a minimum of ¾ in (19 mm) into the roof sheathing.
  
  Where the roof sheathing is less than ¾ in (19 mm) thick, the fasteners shall penetrate through the sheathing.
  
  Florida Building Code also requires a minimum of four fasteners per strip, and, where the structure is within the High-Velocity Hurricane Zone (Broward and Miami-Dade, FL counties), a minimum of six nails are required (Florida Building Commission 2010). Fasteners are either placed by hand or pneumatic air pressure guns.
• See details at ASPHALT SHINGLE NAIL TYPES

Use Staples to Install Asphalt Roof Shingles?

Watch out: the following is an excerpt from a GAF Technical Advisory Bulletin warning about the use of staples to secure asphalt shingles:

Staples are not recommended by GAF and most industry organizations

…Staples made of at least 16-gauge galvanized steel with a minimum crown of 15/16” (24 mm) have been and continue to be used by some applicators to install shingles.

If staples are used to install GAF shingles, our limited shingle warranty will remain in effect.

However any problems resulting from the use of staples, including wind blow-off, are not covered by the warranty.

... Most local building codes do not permit the use of staples…

Details about stapling vs. nailing asphalt shingles including our list of the many ways to make a mistake when stapling shingles are

at ASPHALT SHINGLE STAPLE vs NAIL

...

Fastener Location Requirements for Asphalt Shingle Roofs - Where Do the Shingle Nails or Shingle Staples Go?

Standard shingle nailing for three-tab shingles is four nails per shingle, about 1 inch in from either end and one over each slot.

Shingle nail placement should follow manufacturers specs, which typically require nailing or stapling just below the sealant strip (Figure 2-11 at left).

Nailing the roof shingle too high: can allow wind to get under the shingles.

Nailing the roof shingle too low: will expose nails to the weather and to view from below.

Nailing the shingle through the sealant strip: can interfere with sealing.

Shingle Nailing in Areas of High winds

For areas subjected to high winds, use six nails as shown in Figure 2-11 or add two dabs of sealant at the bottom of each tab (as discussed

at WIND DAMAGE to ROOFS and as shown in Figure 2-7).

Also special wind-rated shingles with heavier sealing strips are available by special order and may be required in some jurisdictions.

See our excerpt from the 2003 IRC R905.2.5 IRC (New Jersey Copy) included just below.

Nailing Requirements for Laminated or Architectural Asphalt Roof Shingles

Use 4 or 6 roofing nails in architectural shingles, as shown here.

With laminated asphalt roof shingles, standard nailing is four fasteners spaced equidistant as shown in Figure 2-12, or six fasteners equidistant for heavy-duty installations.

It is important that fasteners go in the designated nail area where they will penetrate both laminations.

Nailing a laminated or architectural asphalt roof shingle too high will leave the bottom lamination loose and subject to slipping out of place.

R905.2.6 Attachment. Asphalt shingles shall have the minimum number of fasteners required by the manufacturer. For normal application, asphalt shingles shall be secured to the roof with not less than four fasteners per strip shingle or two fasteners per individual shingle.

Where the roof slope exceeds 20 units vertical in 12 units horizontal (167 percent slope), special methods of fastening are required. For roofs located where the basic wind speed per Figure R301.2(4) is  110 mph (49 m/s) or higher, special methods of fastening are required.

Special fastening methods shall be tested in accordance with ASTM D 3161, Class F. Asphalt shingle wrappers shall bear a label indicating compliance with ASTM D 3161, Class F. - IRC 2006 Section R905.2.5

in IRC CHAPTER 9 ROOF ASSEMBLIES [PDF] (2006)

Low Slope Roof Specifications for Asphalt Shingle Roofs: OK with Special Procedures

Asphalt shingles can be installed on roof slopes of 2:12 to 4:12 if special procedures are followed for underlayment.

See details at ASPHALT SHINGLES on LOW SLOPE ROOFS

Steep Slope Limits & Shingle Nailing and Hand Sealing Requirements for Asphalt Shingle Roofs

Asphalt shingles should not be installed on vertical walls, but they can be used on steep slopes, such as mansard-style roofs.

For slopes greater than 21:12, apply underlayment in the normal fashion.

However, shingle sealing may be a problem, particularly on shaded portions of the roof.

For best performance, use the six-fasteners-per-shingle method (Figure 2-11 above) and manually seal the shingles with plastic roofing cement (see manual sealing discussed

at “WIND DAMAGE to ROOFS” ).

Nailing & Sealing Asphalt Shingles on Near-Vertical Building Surfaces

Our steep roof photo (left) shows quite a few shingles lost from this rather steep church roof slope.

Similar problems occur when asphalt shingles are nailed to the steep sides of mansard roofs unless proper nailing and sealing have been performed.

Flickinger cites the NRCA Roofing and Waterproofing Manual 4th Ed where, in referring to roof slopes of 18" rise in 12" of run (150%) or more, [note that this is more cautious than Bliss's advice above] the NRCA (Flickinger) points out that there are differing views within the roofing industry about the maximum slope on which asphalt shingles may be applied using typical methods.

We discuss the recommended installation details for installing asphalt roof shingles on very steep or near vertical roof slopes and also use of roof shingles or even roll roofing on vertical building walls separately

at ASPHALT SHINGLES on VERY STEEP ROOFS

Flashing Requirements for Asphalt Shingle Roofs

Flashings for asphalt shingles should be corrosion resistant metal with a minimum thickness of 0.019 inch. A cricket or saddle should be installed on any chimney greater than 30 inches wide and can be covered with flashing or the same materials used as a roof covering.

See these roof flashing articles:

• FLASHING, ASPHALT SHINGLE VALLEYS
• FLASHING MEMBRANES PEEL & STICK
• FLASHING for METAL ROOFS
• FLASHING ROOF WALL DETAILS
• FLASHING ROOF-WALL SNAFU
• FLASHING SIDING DETAILS
• FLASHING WALL DETAILS
• FLASHING WINDOW DETAILS
• FLASHING WOOD ROOF DETAILS

Underlayment Requirements for Asphalt Roof Shingles

The roof deck should be sound and level before laying the underlayment. Fifteen-pound or heavier felt underlayment is required by code in some areas. Whether or not it is required, underlayment is cheap insurance against problems. There are several good reasons to install underlayment:

• It protects the roof deck from rain before the roofing is installed.
• It provides an extra weather barrier in case of blowoffs or water penetration through the roofing or flashings.
• It protects the roofing from any resins that bleed out of the sheathing.
• It helps prevent unevenness in the roof sheathing from telegraphing through the shingles.
• It is usually required for the UL fire rating to apply (since shingles are usually tested with underlayment).

Details about the requirements and benefits of roofing underlayments are at:

• UNDERLAYMENT REQUIREMENTS on ROOFS
• ROOFING UNDERLAYMENT BEST PRACTICES

Underlayment On Standard Slopes where Asphalt Roof Shingles are Installed

On roofs with a slope of 4:12 or greater, use a single layer of 15 lb. asphalt-saturated felt, starting at the eaves and lapping upper courses over lower by a minimum of 2 inches. Vertical joints should lap a minimum of 4 inches and be offset by at least 6 feet in successive rows (see Figure 2-2 at left).

Secure each shingle course along seams and edges with enough corrosion-resistant nails to hold it in place until the roofing is installed.

In high-wind areas, apply fasteners a maximum of 36 inches on-center along overlaps.

For best protection against leaks, run felt 6 inches over ridges and hips, from each direction, and 6 inches up any adjoining walls. Valleys should be lined with a full width of roofing felt (or bituminous membrane) pushed tight into the valley so there is no slack.

Side courses of underlayment should run over the valley lining and extend 6 inches past its edge.

See ASPHALT SHINGLE VALLEY FLASHING

Underlayment Application of Asphalt Shingles on Low Slope Roofs

Asphalt shingles can be used on roofs with a slope of 2:12 to 4:12 if double-coverage underlayment is used.

Details of that installation are now

at ASPHALT SHINGLES on LOW SLOPE ROOFS

Flashing Recommendations for Eaves and Skylights

Eaves Flashing Recommendations for Asphalt Shingle Roofs

The best defense against ice dams in cold climates is a so-called “cold roof,” consisting of high levels of ceiling insulation separated from the roof surface by a free-flowing vent space

See PREVENTING ICE DAMS on ROOFS.

Where a cold roof cannot be achieved due to complex roof shapes, unvented roofs, or retrofit constraints, ice dams may form during severe winters, in some cases, causing pooled water to wet wall cavities and interior finishes.

Where adequate insulation and ventilation cannot be assured, self-adhering bituminous eaves flashing should be installed. The membrane should go from the lower edge of the roof to a point at least 24 inches inside the interior wall line (Figure 2-5 at left).

See PEEL & STICK FLASHING MEMBRANES

Where two lengths of eaves flashing meet at a valley, run each across the valley, starting with the length from the roof with the lower slope or lesser height. The valley flashing should later lap over the eaves flashing.

See also DRIP EDGE FLASHING for ROOFS

Skylights and Ice Dams on Asphalt Shingle Roofs

With deep snow, melting water from above and around the skylight can lead to ice dams below.

For full protection, some contractors extend the eaves membrane up to the bottom of any skylights and continue it around the sides and top of the skylight.

By wrapping the skylight curb with membrane as well, any potential flashing leaks are also eliminated as shown in Figure 2-5 at left.

See also “Skylight Flashing,” page 127 in the printed text Steve Bliss - Best Practices Guide to Residential Construction - (J Wiley)

If it is impractical to install membrane all the way from eaves to skylight, install a 3-foot-wide band of membrane below the skylight, lapping the bottom edge of the membrane over the row of shingles where the membrane terminates.

Drip Edge. Drip edge should always be used along the eaves to kick water away from the fascia, and it is a good idea along rakes as well.

Drip edge should lap over the underlayment at the rakes and under it at the eaves (as shown in Figure 2-6 at left).

Overlap joints in the drip edge by 2 inches. Shingles can be set even the with the drip edge or overlap by up to 3/4 inch.

Some manufacturers of eaves membranes specify that the drip edge be installed on top of the membrane along the eaves, violating the principle that upper layers of flashing should overlap lower layers.

To remedy the problem, the manufacturers suggest using a second strip of membrane to seal the top of the drip edge to the eaves membrane. In practice, however, most installers place the drip edge first and lap the eaves membrane over it, consistent with good building practice.

- - Adapted with permission from Best Practices Guide to Residential Construction (Steve Bliss, J Wiley & Sons) .

...

Shingle Instructions, Roofing Materials & Equipment Suppliers

• CertainTeed SHINGLE APPLICATORS MANUAL - Landmark® Shingle Series Instructions [PDF] Certainteed Saint-Gobain Corporation, Building Professionals call: 800-233-8990 Consumers call: 800-782-8777 Website: https://www.certainteed.com/ retrieved 2019/09/11 original source: https://www.certainteed.com/resources/LandmarkInstall.pdf
• Certainteed LAMINATED SHINGLE APPLICATION INSTRUCTIONS [PDF] additional advice for English Dimension shingles: Landmark & Woodscape series asphalt shingles & Metric Dimension Shingles: Firehalt, Firehalt 2000, Estate, Architec 80, High Sierra & Landmark Series shingles.
• "GAF-Elk Timberline ® Prestique ® Grande ® 40 High Definition Roofing Shingles Product Information" (2008) GAF-Elk Corporation 5/08 13 61 Alps Road, Wayne, NJ 07470 www.gaf.com, retrieved 9/8/2014, original source: http://www.gaf.com/Other_Documents/ Legacy_Products_Discontinued/Timberline_Prestique_Grand%C3%A9 /Timberline_Prestique_Grande_40_Info_Spec_Sheet.pdf [Note that this is a discontinued product]
• GAF Materials Corporation, TIMBERLINE ROOF SHINGLE APPLICATION INSTRUCTIONS [PDF] (2012) discusses the requirements for successful asphalt shingle installation including the condition of the roof deck, the use of roofing felt underlayment, the selection of roofing nails by type and length and penetration of the roof decking, and the role of glue strips on the back side of asphalt roof shingles.
• Owens Corning, ROOFERS GUIDE to ROOF INSTALLATION [PDF] (2016) Op. Cit.
  Excerpt:
  
  2012 International Residential Code now requires drip edge at the eves and rake edge of the roof. The IRC has required drip edge since the 2009 edition.

Manufacturers

Asphalt Shingles

• Atlas Roofing Corp. www.atlasroofing.com Fiberglass and organic felt shingles
• Certainteed Roofing www.certainteed.com Fiberglass shingles
• Elk Premium Building Products www.elkcorp.com Fiberglass shingles
• GAF Materials Corp. www.gaf.com Fiberglass shingles
• Georgia-Pacific Corp. www.gp.com/build Fiberglass and organic felt shingles
• IKO www.iko.com Fiberglass and organic felt shingles
• Owens Corning www.owenscorning.com Fiberglass shingles
• Tamko Roofing Products www.tamko.com Fiberglass and organic felt shingles

Low-Slope Roofing Membranes

• Duradek www.duradek.com Vinyl roofing and walkable deck membrane
• Firestone www.firestonebpe.com RubberGard EPDM residential roofing system
• GenFlex Roofing Systems www.genflex.com Peel-and-stick TPO membrane
• Hyload, Inc. www.hyload.com Kwik-Ply self-adhering polyester and coal-tar roofing membrane

Ridge Vents

• Air Vent/A Gibraltar Company www.airvent.com A complete line of roof ventilation products, including shingle-over and exposed-ridge vents with exterior wind baffles and internal weather filters. Also soffit and drip edge vents and passive and powered attic turbine-type vents.
• Benjamin Obdyke www.benjaminobdyke.com Shingle-over ridge vents. Low-profile Roll Vent uses nylonmatrix. Extractor vent is molded polypropylene with internal and external baffles.
• Cor-A-Vent www.cor-a-vent.com Shingle-over low-profile ridge vents, including Cor-a-vent, Fold-a-vent, and X-5 ridge vent, designed for extreme weather. Corrugated core.
• GAF Materials Corp. www.gaf.com Cobra vent: roll-out shingle-over ridge vent with a polyester-matrix core 102 CHAPTER 2 | Roofing
• Mid-America Building Products www.midamericabuilding.com Ridge Master and Hip Master shingle-over molded plastic ridge vents with internal baffles and foam filter
• Owens Corning www.owenscorning.com VentSure corrugated polypropylene ridge vents; also passive roof vents and soffit vents
• Trimline Building Products www.trimline-products.com Shingle-over low-profile ridge vents, Flow-Thru battens for tile roofs
• Elk Premium Building Products www.elkcorp.com Highpoint polypropylene shingle-over ridge vents
• Tamko Roofing Products www.tamko.com Shingle-over ridge matrix–type Roll Vent and Rapid Ridge (nail gun version) and Coolridge, which is molded polypropylene with external and internal baffles

Venting Underlayments

• Benjamin Obdyke www.benjaminobdyke.com Cedar Breather, a 3/8 -in.-thick matrix-type underlayment designed to provide ventilation and drainage space under wood roofing

More Information about Roofing Materials, Methods, Standards

• Asphalt Roofing Manufacturers Association (ARMA) www.asphaltroofing.org
• Cedar Shake and Shingle Bureau www.cedarbureau.org
• Metal Roofing Alliance www.metalroofing.com
• Tile Roofing Institute www.tileroofing.org

- - Adapted with permission from Best Practices Guide to Residential Construction (Steve Bliss, J Wiley & Sons).

...