Metal Roof Over Shingles Without Furring Strips

Manufacturers provide 30 year warranties on metal roofing products.

Metal roof over shingles without furring strips. Screw fasten the purlins using fasteners directly screwed into the trusses or rafters. Furring strips are required if you plan to place a metal roof on top of existing shingles. While shingle removal is the preferred route tear off is messy and raises the cost of the job. 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.

Use furring strips to build a slat board on the roof then mount the steel sheets to the slat board. They are compatible with many different kinds of synthetic underlayment. This is by far the most common way to install a metal roof. Metal roofs can be installed over your existing roof without tearing off shingles provided local building codes allow it.

Consult the guide for your shingle brand to determine the specific method of installation required to preserve the warranty. Spacing of furring strips for metal roof when installing a metal roof over an existing roof insulate the spaces between the wood strips with rigid insulation to prevent condensation before. Most metal shingles will be attached to the roof using metal shingle clips but metal roofing shingle installation can be system specific. This should then be followed up with galvanized steel hat channel preferred method or 1 x 2 furring strips.

1 you said some metal roofing should never have firring strips i have certainly seen that with some of the very thin steel or weak aluminum decking which could never stand even a foot of free span over firring strips without crumpling buckling under someone walking on it so they would have to lie flat on the water barrier over the sheathing. Metal roofs depend on thin strips of wood known as furring to allow air to circulate and prevent rot. As long as the plywood under the shingle roof is in good condition this way can provide many benefits. A potential problem with this type of installation is trapped water vapor.

Some consideration for vent stacks and chimneys is required during the design process.