Underlayment For Metal Roofing Over Shingles

Once again this is used on cold roof construction.

Underlayment for metal roofing over shingles.

Advantages of metal roofs over shingles. As long as the plywood under the shingle roof is in good condition this way can provide many benefits. Metal roofs over shingles will also provide an extra layer covering your home helping to further insulate it. To minimize disturbance from such sounds an underlayment for a metal roof is a good idea.

It s installed directly on the roof deck and provides a secondary layer of protection from the elements including rain snow and wind. When hot roof construction is done a roof with no ventilation a breathable underlayment is recommended. The best underlayment for metal roofs. The second way to install a metal roof over a shingle roof is with the use of purlins or battens.

This is by far the most common way to install a metal roof. 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. A layer of underlayment installed on top of the existing shingles will help keep the granules of the old shingles from rubbing against the back of the metal and causing possible corrosion. Disadvantages of metal roofs.

For example if you are putting a metal roof on asphalt shingles then an underlayment can be done without. Therefore it is important that the metal roof underlayment allows moisture that infiltrates the underside of the metal roof to dry out. Underlayment must also act as a secondary weather barrier in case the roof fails. Traditionally metal roofs have used standard 30 pound felt paper underlayment.

The first goal of roofing underlayment is to keep the roof deck dry before installation of the metal roofing material. Make sure the product is designed to be used under metal. Types of roofing underlayment. It serves as a moisture barrier as well as a slip sheet.

This type of underlayment is critical to a quality roof installation. However there are cases where you don t need an underlayment. This method has its benefits as well. If your metal roof is to be installed over solid decking or over existing shingles an environmental benefit a layer of quality underlayment between the two is essential.

Underlayment is also a good idea when the roof is installed over battens though a natural tendency for the underlayment to drop between the battens can be a problem. By placing metal roofing over shingles you can save in the labor costs of ripping them off while also preventing them from being thrown into landfills.