Lots of potential customers ask this question: Do I really have to remove old layers of shingles?
People assume that the more layers you have on a roof, the more protection you have, but that is not exactly true. It is always better to tear off the entire roof: the under-layment, the shingles, and the flashings. The number one reason for doing this is to inspect the underlayment for damage (roof boards). At Quinn’s Construction, we never roof over a single layer of shingles for this very reason.
If you’re thinking of going with another roofing company and leaving the shingles on, consider these facts as well. Even if your current shingles are ideal for installing a second layer, the new shingles will not line up to your current shingles. It creates an apron, essentially preventing the new shingles from sealing well. This can result in shingles blowing off easily in lower winds. Also, if you look at the roof from the ground, it will be visible that the shingles do not line up.
Another thing, has your roof been leaking? Chances are that the under-layment (a waterproof material installed just under your shingles) is leaking. The under-layment is very important because it can keep water out even when your shingles don’t. If your roof is leaking, you should definitely tear off your existing roof and install a new one with the under-layment done correctly. In the event you have two layers, it is important to avoid the temptation to take off the top layer and go over the bottom layer. You will not have a smooth surface to go over with the top layer. If you can imagine all the nails from the top layer that are left behind, you can envision the problems that occur when nails are pounded down, or pulled. Either way, the asphalt shingles in the bottom layer get pretty chewed up!
When a new roof is put on any structure, it is best to replace the flashings as well. Flashings help the shingles seal to the pipes, walls and other roof penetrations in areas that leak most often. During a re-roof it is common for the roofing contractor to seal to the old flashings. Sometimes, these old flashings are not as sound as new ones would be, and they tear off, causing problems for the building owner.
Simply put, the best option when re-roofing, is to remove the first layer and start over.
1. The roof deck (usually plywood or 1x slats) can be inspected for damaged wood that needs to be replaced for strength as well as giving the new roof system’s nails plenty of holding power.
2. You can make sure the under-layment is done correctly, giving the roof a longer life.
3. The shingles will seal down correctly, allowing the sealer strip to hold the shingles together during winds up to 110 miles per hour.
A tear off and re-roof will always have better and longer lasting results. What seems like a lot of extra money spent on a re-roof will actually end up saving you even more money in the long run. Quinn’s Construction will ensure your roof is installed correctly, resulting in less work for you as the building or home owner. Contact us today (978) 957-1200 for a free estimate, or visit our web site: www.quinnsconstruction.com
Remember that much of this roof advice holds true for siding jobs too. Recently, we found this damage (see image) under siding we pulled off before starting the siding work