Does Asphalt Tile Roofs need Underlayment?

Most homes here have underlay , empregnated feltt or moist barrier of a kind for the first 36 inches from the edge. Here there is none in this rainy part of BC West Coast.
Here I lifted the shingle at the edge of the gutter. Is it OK to paste these asphalt shingles directly onto the sheating. ( the roof is 7:12 pitch)
Comment please.

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Hi Jan, I’m not sure what an asphalt tile is, is it the same as a shingle, either way there should be 36" of ice and water sheild inder it to prevent water damage due to ice dams. Hope this helps.

Yes it should have 15 lb felt underlay at least. When the shingles start to go bad as they always will, the homeowner gets temporary relief with the felt, which, if lapped correctly, will direct water back out onto the shingles below.

That thar improperly installed roof does not carry a valid warranty for a home buyer, because I believe the manufacturer would specify underlay.

In my opinion only, the waterProof plastic strip at the eaves is not necessary on the BC coast, where there is no ice damming. It is done anyway to comply w/ Building Code.


They are asphalt shingles, not wood shingles.

Thanks, I should ask the building isnpector for the code they enforce

I am just south across the border from you, and here you must install the 15 lb roofing felt at a minimum.
Besides code requirements, it is also important that the roof covering is installed to manufacturers’ specifications. Every roofing manufacturers directions I have read indicate that at least the 15 lb felt must be installed. If you can figure out who made the shingles, that might also help.

is this 15 lb roofing felt even beneath asphalt shingles or do you mean wood shingles/shakes?

In south floirda a 30lb felt underlayment is required

Roofing felt became widely used in the 1950’s because there were problems with chemical reaction between the asphalt shingles and the plywood sheathing. There is much debate now as to whether it is necessary. IMO, in the N.W. where there is a lot of moisture, I would recommend it, in Arizona, it would be discretionary. Check your local codes. Hope this helps. It is O.K. for the shingles to adhere to the sheathing. Ken

Have you not been to Flagstaff?

Yes it should be under the asphalt shingles.

Here is an example;

Here is Owens Cornings installation instructions for their standard 3 tab;
It includes a recommendation for 15 lb felt.
Notice it states that the underlayment (roofing felt) is required to meet the UL fire rating.

About three years ago I inspected a home that I found had no roofing felt, and the 3 tab shingles had been replaced recently. The homeowner was also a contractor, who stated that he never installed felt on any homes that he roofed. :shock:
So we debated back and forth, and finally I just called up the local AHJ, and they said there were absolutely no exceptions to having the roofing felt. It was required by their standards.

Your local building official may see it otherwise.

The felt adds a back up layer of protection if the roof shingles leak. Just like house wrap under siding (when properly installed)

…Hey at least the roof sheathing in your picture is plywood…and not OSB (was wood) :wink:

Just come back from the ‘den of officialdom’. Our municipal building department said they do not inspect the roof covering, nor the exterior siding, nor the interior cladding (dry wall here). Not for new building nor for any other reason - even though the code may have something to say on it. So it is OK not to use membrane to pass building permits- but it may compromise the warranty, and my report
I will however make a comment in my report that many manufacturers insist on felt or membrane before sticking the ashalt shingles onto the plywood roof sheeting - Thaks for the input everyone !

Here is a Canadian Asphalt Shingle Manufacturers Assoc. Tech bulletin on underlayments.

I am surprised that your local inspections do not cover roofs. But at least now you know.

I think it is good to inform and document the absence of the felt underlayment for your client. Would I suggest removal and replacement of the roof to provide underlayment? Not necessarily. For instance if the roof was getting within a few years of its’ useful life, and there were no leaks, then I would suggest having it installed at the next time it is re-roofed.
I wonder if your local roof certification companies, would even certify a roof without the felt?