When homeowners see the cost of installing a brand new roof, they want to do what they can to reduce those costs. Some contractors suggest adding multiple layers, rather than tearing off the old one and starting fresh. What they don’t tell you is that doing so cuts your warranty in half, lowers your roof’s life expectancy, and makes maintenance almost impossible.
By layer your roof, you’re cutting out the dump and tear-off fees, but you’re adding years of future headache. In Portland, they used to allow up to three layers, but they’ve reduced that code down to two. Once you put on multiple layers, the wind strength goes down and you start losing shingles. I think the city realized it was just a mistake.
The problem is that even with two layers, you cut your warranty in half. You’re going to have less ventilation and holding power. You could also have rot or insects under the top layer and you’d never know. It’s just not going to last.
Maintenance is extremely difficult with multiple layers. In some cases, we can deal with the moss, but as far as leaks go, they are almost impossible to fix. We can sometimes work around two layers, but it’s not easy. With one layer, if there’s an issue, we can take that thing apart, fix the issue, and put it back together easily.
It may look like a good idea initially to save a little money on new roof installation by using multiple layers, but it’s going to cost you a lot more in the long run. Call Roof Life of Oregon for a free estimate, and let’s get you a roof that will last.