My shingles were a little worse for wear and I had a "friend-of-a-friend-who-used-to-be-a-roofer" come take a look at it and he said I could save some money on the demolition by just laying another course of shingles over the first.
He claimed it was a common technique and they did it all the time at his job, but it sounds a little hinky to me.
Is this really commonly done? Is it a good idea? What Are there downsides?
Best Answer
It is common to lay up to three layers (at least in my area), but if the roof has lifting shingles laying another layer will just lift the new shingles. If the roof is bad, it is better and probably cheaper in the long run to remove the old shingles and lay the new ones fresh.
If the roof is not that bad a second layer can definitely save money, just make sure you check your local codes before doing it.
Another concern can be weight. Shingles weigh a lot so the more layers you add the more weight your roof has to carry, if you live in an area with heavy show fall weight could become more of an issue.
Personaly I prefer to start fresh each time, but I save money by doing the demo myself.