Leaks In A 2-Layer Roof

Roofing Over Existing Roof Problems

Lots of contractors offer the option to nail a new roof over an existing roof to save the homeowner money- but this is a common and huge mistake that will cost the homeowner more money down the road. 

Take a look at this one: 

Now that's downright obscene. How many layers is this?! 

Let me explain the dynamics and issues of the 2-or-more layer roof. 

1. The homeowner doesn't want to pay for removal of debris from their old roof while replacing it, so they opt to just have a new roof nailed down over the old 

2. The contractor offers to do a "nail-over" roof. Reason: the price of a rip-off and recycling the shingles in combination with a new install is a huge burden on the homeowner, so just to be able to make some money - the contractor offers the nail-over.  He fails to discuss the ramifications of future problems with such a roof. Why should he? He will lose the sale entirely if he explains. 

3. 2 years down the road after a roof-over-roof job is done, the homeowner starts seeing leaks. Why? 

Who knows. It's possible there was inadequate tar paper under the first roof. It's possible that the second roof is bulging too much and not making solid contact/seals. It's also possible that the nailing was not done far enough into the first roof, creating more holes!

4. The homeowner calls a new roofing company to get the leaks fixed and is told that any repairs that might be attempted will not be guaranteed. Why? because the new roofer has no way to see what's under your top layer of shingles. He can't find the leak source. He can only guess. 

So the homeowner opts to try to repair the leak, and guess what - a few days later in the next rain he/she discovers that it's still leaking.

5. The new roofer is called back to the continued leak problem and he tells the client what he told them before the repair - you need to take the layers off and install a new roof, period. The homeowner is annoyed, they have spent good money and now must spend more, the roofer is annoyed too because he knew that he'd have to do this roof again - and it's more time out of his schedule. He won't be making a lot of money on a 2-layer ripoff, because it costs him more to recycle the shingles. 

Okay - lesson time:

Don't, don't, don't do a nail-over, or roof-over-roof. It doesn't matter if your current roof is about to fall in - just DON'T. 

Leakage problems aside, weight issues also arise from this, causing bad structural damage. Plywood can only stand up to a certain amount of weight, and when you get wet plywood in combination with too many shingles, the weight factor becomes a safety issue. Imagine a leak, with snow on top! Sometimes it's even hazardous for a roofer to walk on such a roof. Rafters begin to fail under these conditions. A broken rafter can mean complicated repairs  - ones where you may have to leave your home in order to get them done. 

In the long run, you're better off saving your pennies for a brand new single layer roof. It's safer for you, safer for the roofer, and will give back for decades to come if you use good materials. Don't go cheap - it'll cost you!