Installing Roofing Over Existing Shingles

Installing a new roof over an existing one also called a layover or nailover is often possible although not always the best option a properly installed layover roof can look and function as well.

Installing roofing over existing shingles.

That s also why building codes commonly limit re roofing to no more than two layers. When roofing over your existing shingles can be a good idea. Doesn t provide the flattest surface for the metal roofing to be installed over each course of shingles is about a 1 8 higher than the course just below it. If conditions are right new shingles laid over old shingles can be just as attractive and durable as shingles laid on bare sheathing.

A steel roof is a lifetime investment lasting 50 years or more if it s a good one. Asphalt roofs typically last 20 to 30 years depending on the installation and shingle quality. But first here are a few precautions about the underlying material. Installation is easier than for a tear off job because you can use the existing shingles as guides for laying the new ones.

Installing new roof shingles over old effectively doubles the weight of the roofing so you have to make sure your roof structure can handle the extra load. Address any existing roof leaks and replace rotten rafters or. If the job is done correctly with the new layer of shingles laid flat over the existing shingles the old roof cushions the new one and serves as a secondary barrier should wind or water ever break through the new shingles. If you choose to install metal roofing over shingles there are certain things you must keep in mind.

But you must take care to install shingles correctly so they lie flat. The felt should be secured every six inches with nails or staples. We re going to break them down so you know what to look out for. Install a layer of roofing felt over the roof before you begin installing the new shingles.

The layers of felt should be overlapped by 1 inch as you work toward the roof ridge. Let s start with the good. 3 install 1x4 purlins down over the shingles before installing the metal roof the third way to install a metal roof over shingles is by applying 1x4 purlins over the shingle roof. Why installing new shingles over old shingles can be good.

All shingle manufacturers honor the warranty whether their products are used for a reroof or a new roof. When you should tear off your roof and start from scratch instead.