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H i n t s & T i p s A s p h a l t S h i n g l e s
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Click here for the Overlay/Recover section
- The roofing materials should be kept dry until installation. If materials are stacked on
the ground, the materials should be placed on pallets or other type of raised platform and
covered with a weather protective covering.
- Inspect the bundles for moisture upon delivery. If the bundles are wet, the shingles
should be allowed to dry completely before installation. If shingles are installed wet,
then problems will occur later on such as blistering, mold, mildew, etc.; all of which
expedite roof deterioration.
- NEVER USE STAPLES! A really good type of nail to use in roofing applications is a
"Hot-Dipped Galvanized" nail. This type of nail is dipped in a bath of molten
zinc. Do not confuse these nails with "Hot Galvanized (H.G.)" nails which are
coated by tumbling them in a mixture of zinc chips inside a hot furnace. A couple of types
of nails that aren't recommended are "Electroplated" (A.K.A. Electrogalvanized or E.G.) and "Mechanically-Plated" (A.K.A. Peen-plated or
golden-galvanized). These two types rust quickly when exposed to weather and moisture.
- Two layers of underlayment should be used on slopes less than 4:12. Click HERE for an example.
- For recommended underlayment nailing patterns, click HERE.
- For recommended high wind underlayment nailing patterns, click HERE.
- Nails should be long enough to penetrate the wood decking a minimum of 3/4". A
general rule of thumb is to use 1-¼" nails in reroof applications when the old roof
is torn off and to use 1-½" nails when overlaying the old roof. Click here for more.
- Use a minimum of four (4) nails per shingle, or six (6) nails per shingle in high wind
areas and six (6) nails per shingle on slopes exceeding 12:12, or 12
inches of rise for every 12 inches of vertical "run" (a 45 degree
angle).
- When replacing decking material, it is recommended that it be replaced
with half sheets
(4'x4'). You want the decking to span 3 rafters. A 4'x4' sheet will span
3 rafters spaced 24 inches apart. Do not "piece" in decking.
- Use a dense nailing pattern for installing the underlayment. That way, if the shingles
blow off, then the felt should still be there to help provide protection. For an example,
click here.
- When placing decking over rafters set on twenty-four inch (24") centers, it is
recommended that minimum 5/8" decking be used.
- When installing shingles on a roof with a slope that is less than 4 in 12 (33%), it is
recommended that two (2) layers of number fifteen (#15) asphalt saturated felt
underlayment be installed in shingle
fashion.
- Ice and water protection membranes should be installed in
regions where the average January temperature is below freezing (32° F, 0° C). The
membrane should extend from the bottom edge of the roof, past the interior wall line a
minimum of twelve inches (12").
- It is always a good idea to place an ice and water protection
membrane in all valleys.
- For Starter shingles, you can use 3-tab, self-sealing shingles with the tabs cut off.
- Always nail shingles ON THE NAIL LINE.
- Galvanized edge metal (drip edge, nosing, etc.) should be rubbed with white vinegar or
diluted muriatic acid (HCl) prior to priming and painting.
- Paint your roof penetrations and flashings the same color as your fascia to improve
aesthetics.
- Do not install ventilation devices halfway up your roof. Install them at the very top.
Installing roof vents between the intake and exhaust vents will cause a ventilation short circuit.
- For proper ventilation, you should have an under-eave soffit ventilation and ridge
ventilation installed at an area ratio of 1:1. In other words, for every square inch of
soffit ventilation you should have a square inch of ridge ventilation.
- All raggles should be a minimum of 1"
deep.
- If installing gutter, try to use straps instead of nails and furrels. Nails can pull out
of the fascia if your gutter fills up due to plugged downspouts.
- Never install wood decking directly over wood decking. Wood decking needs to be able to
"breathe" on one side or else severe warping can occur.
- You shouldnt install most shingles in temperatures less than 40° F because
shingles are brittle and can crack. However, there are shingles currently on the market
that have been installed in 0° temperatures. These shingles are manufactured from SBS
modified asphalt.
- Install the drip edge material over the underlayment along the rakes and under the
underlayment along the eaves.
- Keep all oils, greases, and chemicals off of the roof.
- The nails you use to install your hip and ridge cap should be approximately 1/2"
longer than the nails used on the main sections of the building. This is because the
hip/ridge nails generally have at least two extra layers of material to go through.
SPECIAL
CONSIDERATIONS FOR OVERLAYS (RE-COVER)
- Visit http://www.roofhelp.com/tearoffvsoverlay.htm
before proceeding.
Inspect the bundles for moisture upon delivery. If the bundles are wet, have them
returned and exchanged for new ones. If shingles are installed wet, then problems will
occur later on such as blistering, mold, mildew, etc.; all of which expedite roof
deterioration.
Remove any curled shingle tabs. You want the substrate of the new roof to be flat. Use a
flat nosed shovel as it works the best.
Make sure the existing roof is dry before you shingle it. Trapped moisture such as dew
will shorten the lifespan of your shingles.
Don't overlay a roof with algae problems unless you
clean it first.
Before you start, cut the existing shingles back approximately ½" to 1" from
the edge of the roof all the way around. If you install new drip edge, make sure that it
covers the old drip edge material or else it will look ugly. Install a starter row along
the eaves.
When overlaying an existing shingle roof, DO NOT install a layer of felt between
the systems.
Tear off the hip and ridge cap before you start or else it will cause a large hump in
the roof along the hips and ridges.
Nails should be long enough to penetrate the deck a minimum of ¾". 1 ¼" to 1
½" nails are generally used in overlay applications.
The nails you use to install your hip and ridge cap should be approximately 1/2"
longer than the nails used on the main sections of the building. This is because the
hip/ridge nails generally have at least two extra layers of material to go through.
Install all new flashings. Remove the old flashings and fill in the void that it causes
with shingle material.
Use four (4) nails per shingle minimum, six (6) nails per shingle in high wind areas.
Check with your local building department prior to overlaying the existing roof. Some
cities/regions allow only two layers of roofing while others allow three layers.
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