This is by far the most common way to install a metal roof.
Metal roof over shingles without furring strips.
Metal roofs can be installed over your existing roof without tearing off shingles provided local building codes allow it.
If talking strip metal roofing like standing or raised seam then i can t imaging getting an even final surface or proper fastening without firring strips not only because putting the metal right on the shingles gives no way to level out the uneveness of the old shingles but also the underlying shingloes and underlayment will get awful hot.
Use furring strips to build a slat board on the roof then mount the steel sheets to the slat board.
Metal roofing is also available in the form of shingles.
If your home s existing shingles are pretty curled you could install a textured metal roof such as a metal shingle shake or tile directly over the curled shingles along with underlayment.
If you opt to put the metal roof atop current roof shingles it needs to be done in combination with a synthetic underlayment recommended.
You also could install a corrugated through fastened metal roofing product and probably not have issues.
Installing steel roofing over existing roofing materials is fairly simple.
Screw fasten the purlins using fasteners directly screwed into the trusses or rafters.
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.
While shingle removal is the preferred route tear off is messy and raises the cost of the job.
As long as the plywood under the shingle roof is in good condition this way can provide many benefits.
This should then be followed up with galvanized steel hat channel preferred method or 1 x 2 furring strips.
Work up from the initial row starting at the lower corner in a diagonal pattern staggering the shingles to prevent gaps.
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.
A potential problem with this type of installation is trapped water vapor.
Lay the starter row of metal shingles at the drip edge and affix to the roof with metal roofing nails.