It’s probably one of the questions professional roofers hear most often. Installing new shingles over an existing roof is appealing to many homeowners, because it avoids the time, cost, and mess of tearing off the current roof. However, there are some significant possible drawbacks, as well as some things to keep in mind if you decide to go ahead and shingle over an existing roof.
Is it possible to put new shingles over old ones?
Maybe. Most areas have codes that limit the number of layers of shingles to two. The reason is that a house is not made to withstand the weight of more layers than that. If you only have one layer of shingles, it may be permissible for you to add a second. You should consult with your municipality or a roofing professional to understand what’s allowed in your area.
Should I put new shingles over old ones?
This is a more complicated question. Here are some of the pros of adding new shingles over old:
· It is less expensive in the short-term because it cuts out the cost of tearing off and disposing of the old shingles.
· The job will be quicker without the tear off portion.
· It’s a lot less messy and doesn’t involve dealing with the debris of the old shingles.
Here are some of the cons:
· You are really just deferring the cost. When you replace your roof next, you will have to pay more to tear off and dispose of two layers of shingles.
· Not removing the old shingles means you can’t see what’s underneath them. There could be wood rot or water damage that isn’t visible with the old shingles in place. Laying new shingles over old ones that are covering damage of some kind could result in much more extensive damage—and much more expensive repairs—later.
· You may compromise your warranty and lessen your leverage when it comes to selling your home. Laying new shingles on top of old ones may void the warranty that comes with the new shingles, and may be a drawback on a home inspector’s report if you are looking to sell your home. Many home inspectors note this on their reports because of the potential risks that come with putting new shingles over old.
It’s really tempting to go with adding a new layer of shingles instead of tearing up the old ones first. It’s more convenient and less expensive up front, but there are significant drawbacks to consider before choosing this option. When weighing the pros and cons of the different ways you can repair or replace your roof, remember to consult a professional roofer who can help you assess your situation and make a decision that will bring the most value to you and your home.