Would you recommend re-roofing over a single layer of asphalt shingles?

Answer: In some cases
Explanation: If only one layer yes.

Answer: In some cases
Explanation: LEARN MORE: https://4squareroofing.org

Answer: In some cases
Explanation: The short answer is yes, you can lay new roof shingles over top of the old ones (with asphalt), but there are other factors to take into consideration. Placing old shingles over new ones is only possible with asphalt shingles, also known as composition shingles. You cannot place a new layer over top of slate or wood, and you should definitely never mix materials like laying asphalt shingles over cedar shakes. Perhaps the most important rule for laying new shingles over top of old ones is that the old roofing has to be in pretty good condition. If you are laying new roofing shingles over an existing roofing system with a ton of leaks or damage, you aren’t doing yourself any good. It might seem like an obvious benefit to having multiple layers of protection on your roof, but that is not automatically true. As a matter of fact, having multiple layers of shingles does not mean that your roof is any more waterproof than it may have been before. Also, having multiple roofing layers can create problems all its own. The biggest reason to lay down new shingles over existing ones comes down to a simple matter of convenience and cost. Keeping the old shingles allows you to skip the messy labor and disposal costs of a tear-off.

Answer: In some cases
Explanation: Recommended by ARMA as a green solution

Answer: Never
Explanation: Of 800 installations, I have only done three shingle over projects.

Answer: Never
Explanation: As a MasterElite installer we cannot roof over existing shingles and for the cost and longevity it's more cost effective to install a new roof entirely.

Answer: Never
Explanation: A new roof is an expensive undertaking. The life of the new shingles installed over the old ones will be cut in half or more. The next time the roof fails you'll have to pay to strip off two layers instead of one. Also, by not removing the old shingles you won't know if rotted wood needs replacing, flashing needs replacing or ice and water barrier needs to be installed not to mention warranty issues. The smart way is to strip the roof down to the decking, make repairs if needed and install all components fresh and new.

Answer: In most cases
Explanation: in most cases I would always roof over a single layer unless there is dryrott issues with the sheeting under roof

Answer: Never
Explanation: We do not recommend doing so. While it may seem cheaper to do so, in the long run, it can cost more to so. The weakest point in your roof is the underlayment material. Most roofs are done with felt paper underlayment which absorbs moisture and begins to fail after about 10 years. If the roof is worn out and needs replacing, then the underlayment is also bad and will offer no protection. The worn out shingles now become your underlayment, a job that they were not designed to perform. At Allegiant Roofing we will always recommend removing all worn out materials and installing new materials to provide the longest life roof possible.

Answer: Never
Explanation: It has been proven that a double layer on a roof is a bad thing and will decrease the life of the roof sheathing (plywood). In most cases when we remove a double layer roof, there is almost always an abundance of plywood to be replaced. In addition nowadays home inspectors know a double layer is a bad thing and if you go to sell your home, chances are they will be asking for a credit to replace the roof regardless of how old the top layer is.