A common question we get in the roofing industry is: is it ok to put shingles on top of the existing ones?
Your roof is a expensive investment and we can understand that you want to save money where you can, however trying to save on tearing off the old roof by putting new shingles on is not advised. Doing this can cause a number of problems such as voiding your warranty, adding extra weight to the home, and it greatly diminishes the life of your roof.
Don’t Pinch Pennies Now to Spend More Later
A lot of times with clients, it may look better to save money up front. There are contractors out there that are willing to shingle over your existing roof. They might even make it sound like an amazing deal. The truth is though it’s not. When you add another layer of shingles there are a number of things that could end up costing you more money in the end. Here’s why:
When you add a second layer of shingles, it can make it very difficult to locate leaks to properly repair them. Generally, you will see more repairs on layered asphalt shingles because the first layer of shingles will break down more quickly and retains moisture. Retained moisture will rot your decking as well as increase the chance of mold and mildew building in the home. To fix this properly you would need to take shingles off to find the leak and because there are two layers it instantly becomes more expensive.
Your roof isn’t just plywood nailed to your rafters with shingles on it. In fact, if installed correctly, there are several components that go into make it function optimally. When you add a second layer of shingles on your home, you greatly diminish the life of the roof. For your shingles to function optimally, they need to have great ventilation. When you layer over shingles, the top layer can cool itself down the same way it would sitting over a ventilated attic. This will cause the granules to heat up on the shingles to fall off quicker and lower the life of the roof.
It’s a fact! If you put an extra layer of shingles on, there is not a reputable company out there that will offer a warranty. The majority of shingle and roofing component manufacturers will not offer a warranty because they have very specific guidelines on what needs to be on a roof to offer warranties. Roofing technology in the past couple of decades has proven that if a roofing system is installed correctly and with the proper ventilation, it will last much longer than adding a layer to an existing roof.
Other Things to Consider…
If you are thinking about buying or selling a home that has two layers of shingles, keep in mind this comes in to play as well. Most home inspectors out there will suggest having it replaced. Most insurance companies don’t want to cover a layered roof which can be frustrating for a home buyer or seller. Home buyer’s may not want to make such a big investment if they know about a major renovation like a roof. That can affect how easy it becomes to sell the house.
Extra layers of shingles can also be a problem structurally and aesthetically. The extra weight that can be a burden on your home and it would need to be properly reinforced. The extra weight will eventually cause the boards between your rafter to bow and make the roof look wavy which could also make it a difficult sell.
Is it cheaper up front? It can be. Is it worth it in the long run? Absolutely not! Save yourself the time, money, and effort and do it right the first time! Follow the link below to schedule your inspection!