Q & A - Tearing off a Roof, The Pro's and Con's

Barbara asked, "Can we lay over a roof that leaks?"

"I am the president of a condo association. Our units are now 18 years old and need to be re-roofed. We have a few elderly men in our community who insist that we lay over the existing shingles rather than tear off and shingle. They say the difference of the life of the two methods is two years. We’ve had many, many leaks over the years. Apparently the valleys were put in wrong. The leaks happen mainly when we have hard rains, but they have leaked other times. My question is, can we lay over roofs that leak? And is it accurate that the difference of the lifespan of the two methods is two years Thank you very much for your attention to this, and I look forward to your response."

Barbara,  In my opinion, it is a far better job to remove all roofs, leaky or not, then attach the new roof directly to the deck.

Here is why:

1. Dry rotten wood can now be seen and taken care of.
2. The new roof will lay down flat and look nicer.
3. Old flashing can be replaced on a torn-off roof.
4. Oversized edge metal, must be used to cover existing rake and eave metal.
5. Weight of two roofs could exceed roof design.

Doing a recover saves money in tear-off cost but with a leaking roof unseen dry rot is hard to repair and discovery later will cost you more in the long run. Your leaky valleys could have many issues you can not see without removing the roof.

Most manufacturers warranty the roof the same, torn off or not. A recovery or “layover” is an acceptable installation with certain preparation done.

A proper recovery should have this prep done:

1. All the ridge and hip caps need to be removed.
2. Any multiple shingle layers overlapping the ridge and hips need to be removed.
3. All wall to roof area removed and properly rewoven shingles and step flashing.
4. All roof flashing removed and replaced.
5. All shingle edges trimmed back and cleaned up.

This cost can run upwards of 35 % of the cost of a tear-off.

Why people don’t tear off a roof.

1. Flippers just are going to sell out.
2. Not planning to be there when the next roof is needed.
3. Needs to save money.

Barbara, I hope this short answer helps you and your association.

Send photos of your roofs for a better understanding of your project, I am interested in what happens.

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