Snap a chalk line horizontally across the roof two feet down from the top.
Installing metal roof with purlins.
When installing a metal roof over an existing roof insulate the spaces between the wood strips with rigid insulation to prevent condensation before installing the roofing.
Lay the starter row of metal shingles at the drip edge and affix to the roof with metal roofing nails.
Do all roofing projects require purlins.
Purlins are non pressure treated 1 x 4 x 12 lumber that is installed on to the roof in a specific layout pattern and screw pattern.
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.
The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to.
Installation of pole barn purlins.
How to install metal roof purlins step 1.
During the roof installation or re roofing process after the roof sheets are prepared it is time to support their framework by installing purlins.
Always begin working at the point with the longest peak to eave distance.
The purlin are ultimately used to fasten the roof steel providing a diaphragm effect along with the siding when properly engineered and installed.
Take your first sheet of metal and place it on the roof so that it overhangs the edge at least 3 4 in 1 9 cm.
Purlins are dimensional lumber that are fastened to the top chord of trusses connecting them together for bracing purposes.
As long as the plywood under the shingle roof is in good condition this way can provide many benefits.
Spacing is typically 24 on center in low snow loads and is reduced based upon truss span and snow load.
Set the second.
This is by far the most common way to install a metal roof.
Take care the first piece is aligned precisely perpendicular square to the edge.
You also need to add.
Lay the first purlin at the ridge of.
Add the metal panels.
Run a tape measure from end to end along the rafters of the roof to determine how many purlins will be needed.