Construction & Contractors Blog
A question that sometimes comes up when you have a roof replacement is if your new roof can be put over the old one. This is a question your roofer can answer based on the condition of your roof and other factors. However, the best choice might be to tear off all the old roofing first. Here are three reasons to remove your old asphalt shingles before putting on new ones.
1. The Warranty On Your New Roof Could Be Voided
If you and your roofer decide to add a second layer of roofing, be sure to check the conditions of the warranty for your new roof. The asphalt shingle manufacturer might not honor the warranty if the new shingles are installed over the old ones. Protecting the warranty is important so you can get the roof replaced in case of a manufacturing defect.
2. The Roofer Can't See The Deck With The Shingles On
When the roofer tears off an old roof they can see the deck and examine it for rotted areas. When the rotted deck is removed, they might find rotted rafters that need to be repaired too. This type of damage won't be seen and found if the old shingles stay in place. Water damage can lead to the spread of rotting and mold growth, so it's essential to ensure the old roof deck is dry and in good shape before new asphalt shingles are put on.
3. The New Roof May Not Last As Long
Since a new roof costs a lot of money, you probably want it to last as long as possible. The life of your new roof might be cut short if it is installed over an old roof. Nails from the old roof might back out and damage the new shingles. If the new shingles aren't nailed in tightly, wind might lift the shingles and make your roof more susceptible to wind damage. Your roof will also have extra weight on it, and that might affect the deck, especially in areas that are rotted. The plywood may not be able to hold up the weight of two layers of shingles.
Your roofing contractor can help you understand these potential risks of having two layers of asphalt shingles. You may find the risks acceptable and decide to go ahead with adding a second layer of shingles, but you might decide the risk of roof damage isn't worth it. In that case, the roofer will tear off all the old roofing so your deck can be examined thoroughly and made ready for a complete roof replacement.
Share4 August 2021
