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No felt beneath asphalt shingles.


Bain
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I'm currently inside a house that has no felt underlayment beneath the asphalt shingles. The bloody things were nailed directly onto the OSB decking. I realize there's no code in place barring this practice, but does anyone know if manufacturers as a group require felt beneath the shingles?

Many insurance companies require felt to maintain fire ratings, and won't pay a claim on a fire-damaged house with no underlayment, but I don't have tons of time to Google here while I'm on-site. Any help would be appreciated.

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Originally posted by Bain

I'm currently inside a house that has no felt underlayment beneath the asphalt shingles. The bloody things were nailed directly onto the OSB decking. I realize there's no code in place barring this practice, but does anyone know if manufacturers as a group require felt beneath the shingles?

Many insurance companies require felt to maintain fire ratings, and won't pay a claim on a fire-damaged house with no underlayment, but I don't have tons of time to Google here while I'm on-site. Any help would be appreciated.

The NRCA recommends it in section 2.2. You can view the manual online here:

http://www.nrca.net/rp/technical/manual/manual.aspx

- Jim Katen, Oregon

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"R905.2.7 Underlayment application. For roof slopes from

two units vertical in 12 units horizontal (17-percent slope), up

to four units vertical in 12 units horizontal (33-percent slope),

underlayment shall be two layers applied in the following

manner. Apply a 19-inch (483 mm) strip of underlayment felt

parallel to and starting at the eaves, fastened sufficiently to

hold in place. Starting at the eave, apply 36-inch-wide (914

mm) sheets of underlayment, overlapping successive sheets

19 inches (483 mm), and fastened sufficiently to hold in

place. Distortions in the underlayment shall not interfere with

the ability of the shingles to seal. ***For roof slopes of four units

vertical in 12 units horizontal (33-percent slope) or greater,

underlayment shall be one layer applied in the following

manner. Underlayment shall be applied shingle fashion, parallel

to and starting from the eave and lapped 2 inches (51

mm), fastened sufficiently to hold in place."

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Originally posted by inspecthistoric

"R905.2.7 Underlayment application. For roof slopes from

two units vertical in 12 units horizontal (17-percent slope), up

to four units vertical in 12 units horizontal (33-percent slope),

underlayment shall be two layers applied in the following

manner. Apply a 19-inch (483 mm) strip of underlayment felt

parallel to and starting at the eaves, fastened sufficiently to

hold in place. Starting at the eave, apply 36-inch-wide (914

mm) sheets of underlayment, overlapping successive sheets

19 inches (483 mm), and fastened sufficiently to hold in

place. Distortions in the underlayment shall not interfere with

the ability of the shingles to seal. ***For roof slopes of four units

vertical in 12 units horizontal (33-percent slope) or greater,

underlayment shall be one layer applied in the following

manner. Underlayment shall be applied shingle fashion, parallel

to and starting from the eave and lapped 2 inches (51

mm), fastened sufficiently to hold in place."

Ah, so. Thanks.

- Jim Katen, Oregon

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Thanks for the quick replies, everyone.

I loathe the gray areas of our bidness where something is performed at a bare minimum level of acceptance, but you can't actually call it wrong.

I mean, what if the shingles were installed during the winter and they didn't seal properly? Rain would slant in through the gaps and destroy the decking.

FYI, the undersides of the decking were pristine in the attic.

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Can any of our Wisconsin folk verify that felt is not a requirement in their lovely state? Think I heard this was a newer-something *less-requirement* as of couple/few years ago.

If so, seems weird for a state where the most oft-heard last words of the males inhabiting the great north woods are "hold my beer and watch this..."

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Originally posted by Jerry Simon

Can any of our Wisconsin folk verify that felt is not a requirement in their lovely state? Think I heard this was a newer-something *less-requirement* as of couple/few years ago.

If so, seems weird for a state where the most oft-heard last words of the males inhabiting the great north woods are "hold my beer and watch this..."

(3) WATER. All roofs shall be designed and constructed to

assure drainage of water.

(a) Roofing. 1. ‘General.’ a. Underlayment consisting of

number 15 asphalt#8722;impregnated felt paper or equivalent or other

type I material that shows no water transmission when tested in

accordance with ASTM D 226 or ASTM D 4869 shall be provided

under shingles.Note: Underlayment materials meeting the requirements of ASTM D 1970 meet

the performance requirements of this section.

b. Fasteners shall be corrosion resistant

We do not fall under the IRC. We have are own code section that is a derivative of the IRC the UDC.

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  • 2 weeks later...

I also wish to stress that local codes throughout the USA vary immensely with regard to underlayment.

In reality, felt underlayment is not a moisture barrier in regards to

manufacturers warranty.

Felt under shingles is not considered a moisture barrier.Felt can be a temporary moisture barrier, if secured properly, before the application of shingles. Once shingles are applied the felt is no longer a moisture barrier.

Jim C.

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