Roof followup question.

A number of responses that I received to my earlier question alluded to multiple layers of shingles. While I've heard of this, I always wondered whether it was a good idea. Any problems associated with simply putting down one layer on top of another? Does your existing roof have to be leak-free in order to make this work? Any situations where it should be avoided? I wouldn't mind saving some bucks if this is the way to go. I hope to be living in Boca Raton in a retirement community by the time I need to replace the next roof. :>) TIA,

I can put another layer on top. Only problem is if you have very poor shingles (i.e. folding up, etc.) you will need to take them off.

The real water proofing is the felt paper below the shingles. The shingles just protect that paper from the sun and hail. If you are leaking, you need to get to the paper/flashing to fix the real problem.

If you were selling, and the buyer was getting an FHA loan, then FHA only allows 2 layers max. You can add a layer to a single layer, but not to multiple layers.

Also any deficiences in the existing layer would need to be addressed prior to covering.

Adding a layer of shingles on top of an old roof CAN be done....but is not advised. It will shorten the life of the new shingle. Roofing felt is just a vapor barrier between the house and the roofing. I have seen MANY houses roofed without a single layer of felt on them. I guess the builders were trying to save a little money.! No...I haven't seen this in Arkansas.....but did see it a great deal in Huntsville, AL when I lived and worked there. I have done a LOT of roofing in my days and always put down new felt.

The other thing to consider? WEIGHT and if your existing roof framing can support the additional weight of a 2nd roof layer. 20 Year shingles weigh 75 pounds per bundle or 225 pounds per 100 square feet. Multiply 225 pounds time 27 (the approximate number of squares your roof will need to completition) and you get 6,075 pounds....plus addin the weight of nails...50 pounds plus add the weight of the felt....40 pounds per roll if it is the 100 sq ft coverage rolls.......Let's just say you are adding over 3 TONS to your roof.......can your framing support another layer of "standard" shingles? Will adding the 2nd layer void your warranty of the new roof? Here....the 2nd layer voids any warranty of the new roof.

Just my experiences and 2¢ worth on this.

Yeah, I was recently faced with the same decision. Some localities' building codes don't let you put more than one layer; almost all forbid more than two.

Layering over is cheaper (no dumpster, disposal, tear-off labor).

But taking the old stuff off helps you make sure you address any problems. We went with taking the first layer off.

- Ed

Guess I'm looking at a complete tearoff. Cheers!

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Originally Posted by Hal Flynt

If you were selling, and the buyer was getting an FHA loan, then FHA only allows 2 layers max. You can add a layer to a single layer, but not to multiple layers.

Also any deficiences in the existing layer would need to be addressed prior to covering.

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Not all FHA are that way...we bought our house FHA and it had 3 layers of very crappy shngles on it, and it passed. Here in IL, they wont let you have more than 3 layers...that's max. You really need to consider the weight of all the shingles. I had them tear mine off..they had to, 3 layers...and I'm sure my roof gave a big sigh of relief! You'll be happier in the long run if you tear off..I'd check your local building code to see what your max. layer amount is, don't go by wht the roofing company says! DAMHIKT!

I think the industry standard is no more than three layers and it depends on the locality. Here in Calif you can go up to three layers of shingles but tar and gravel roofs (flat) have to be stripped each time.
Here you also have to get a permit in most cases so you need to check with your local county/city office. Just call but don't give your name or address. they will also tell you how many layers you can max out at. Our county office is very free with information without requiring any from you.

Hi Tony,

If there is not sheeting on the roof I would sheet it also. I put a new roof on my Grandma's 100+ year old house last summer. It is faster and easier to put shingles down on the sheeting than on to boards. You always have something to nail to and no gaps. I did not sheet the sides (barn style roof with steep sides then the less steep top) and I had problems under the one dormer with a gap between the boards. You don't want to hear this with the huge jump in sheeting cost but it is what I would do.

Worth what you paid for it :)

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Originally Posted by Tony Sade

Guess I'm looking at a complete tearoff. Cheers!

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Here in Dallas, Tony, you can't get insurance with composition over wood shingles, period. Used to be one layer, now, no more. Tear down to the rafters, if not previously done, and deck it with cdx or cool deck plywood. It ain't an old mans job. Hire a reputable outfit, is my suggestion. ;)