When contemplating a new roof, many people hope to simply do a shingle over and avoid the extra cost and mess of tearing off the existing roof and starting from scratch. Although it sounds like a good idea, we can assure you the cons heavily outweigh the pros. In fact, the ONLY pro to a shingle over is it’s cheaper and cleaner. The problem is, what if there is an unknown leak or bad roof flashing? Will it be fixed? Will the damaged wood be replaced during a shingle over? Unfortunately, the answer is no.
Just the other week, we came across a leak around a dormer the homeowner never knew about. Obviously, during the tear-off, we spotted the leak and were able to change out the rotted wood and re-flash the area. In a shingle over, if some of the decking has buckled and warped over the years, it likely isn’t going to be noticed and fixed. This can lead to increased rot, mold, and decrease the structural integrity of your home.
Long-Term Effects of Shingling Over Shingles
Apart from the problems going unnoticed during the actual shingle over, there are long term effects to consider as well. For instance, instead of just one roof on your home, you now basically have two. That’s a lot of extra weight, putting added stress on the roof decking. Also, two layers of shingles are going to attract a lot more heat than just one layer, which can lead to the shingles prematurely deteriorating. Also, what about all the algae growth and bacteria on the original layer of shingles? Now everything is trapped under the 2nd layer of shingles, again having the potential to shorten the lifespan of the top layer of shingles.
Roofing Over Your Existing Roof Is Not Worth It
If you haven’t noticed yet, we are not fans of shingle overs – not at all. We don’t recommend them nor do we do them. Over the years, we’ve seen problems caused by shingle overs. Does it cost more to tear off? Yes. However, by spending a little more now, you can save yourself thousands in the long run.
