An over-tightened fastener will pull down the cladding locally and can create deformations. There are two ways to do this – put in firringnailing though nails are not used any more for this strips or purlins in steel frame construction on the roof to support it or place the metal roofing directly on a flat surface like foam insulation board or the roof sheathing with roof water barrier in the correct position in the layer.
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Metal roof over shingles furring strips. If you opt to put the metal roof atop current roof shingles it needs to be done in combination with a synthetic underlayment recommended. The low weight of metal encourages this. Screw fasten the purlins using fasteners directly screwed into the trusses or rafters.
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. This is the fastest way to install but it doesnt provide the flattest surface for metal roofing installation. Oct 19 2019 If you wish to install metal roofing over shingles its recommended to do it one of two ways.
Is it necessary to patch these spots as well or will the felt and strips be level enough to screw the metal straight to it. As long as the plywood under the shingle roof is in good condition this way can provide many benefits. Step 4 Install Edging.
This is by far the most common way to install a metal roof. Grand Rib 3 style roofing can be applied over existing shingles provided the integrity of the roof decking and framing has been checked by a qualified party. If you opt to do this youll benefit from using furring strips and a waterproof barrier first.
This should then be followed up with galvanized steel hat channel preferred method or 1 x 2 furring strips. Can you put metal over shingles. Feb 01 2019 While sometimes caused by inferior metal or too-low-gauge thickness too often it is caused by under- or over-tightening of roof fasteners that causes the metal to stretch pull and dimple in various directions.
The second way is to install 14 purlins over the shingles. Standing seam roofs may have unevenness of the old shingles telegraphed through and cause ripples in the standing seam. The furring strips are 1×4 pine boards.
There are several spots on the back side missing shingles. It is easier to do with more heavily textured metal roofs such as exposed fastened corrugated products and metal shingles. The first is to apply an approved underlayment over the old shingles.
Jan 24 2019 3 Install 14 Purlins down over the Shingles before Installing the Metal Roof The third way to install a metal roof over shingles is by applying 14 purlins over the shingle roof. Bend the metal edging to your needs if necessary and fasten it to the roof with nails at. Mar 26 2015 Many many metal roof installations are over existing shingles.
Install the slat board as described above. Secure them to the roof with wood screws at every 4 to 6 inches. The use of underlayment between the shingles and metal roof panels is a standard practice.
If you think that is overkill and youll have an unheated shed then you can screw directly through the shingles. You need to check the installation instructions from the manufacturer – depending on whether the purlins firring strips are 1x or 2x material and how wide thickness metal gage of roofing steel or aluminum type of seams design wind and snow loading whether designed to be walked on or not etc I have seen it vary from as little as 4 inches clear gap between firring strips on lightweight aluminum to as much as 4 feet on very heavy gage steel standing seam roofing. You can use metal roofing over old shingles.
Jun 08 2017 My question is before I prep for the metal roof how flat does the roof need to be before I lay down the felt and furring strips.