Unlike other types of roofing, most metal roofing is made up with a standing seam as this allows the panels to intersect on top of each other along the edge. To screw down the metal roofing, the frame should be very much sturdy and strong to hold a heavy weight. Usually, a ¾ inch plywood or 5/8 oriented strand board is installed over the roof deck with the roof rafters evenly given a 24 inch space from centre to centre. Here are the instructions on how to frame a metal roof.
1. You are to measure the ridge beam and the top of the wall and mark it for every 24 inches. A rafter hangar should be installed on each of the mark on the ridge beam, to screw down metal roofing to a solid frame you need to screw the left hole of the bracket and leave the right side open as to fit the rafter in.
2. A hurricane tie bracket is to be attached on the mark at the wall and fit the rafter to their position. Align the hurricane tie with the bracket and lift the right side and drive a screw into the hole on right side of the brackets. The bracket should be attached to the rafter and then to the ridge beam. The bottom end of the rafter is attached to the hurricane tie by the hole screwed through the bracket.
3. Install the deck in the left corner of the roof by using a ¾ inch thick plywood and align the left long edge with the outside rafter with the bottom end of the first sheet with its end to the rafters. Use 1 inch nails to nail the decking into the rafters after every 12 inches.
4. Before you screw down metal roofing, fit the sheet flush to the right edge of the sheet with its bottom end even as the rafters end and nail it. Add the sheet flush to the sheets before and measure it till the end of the roof and cut it to fit.
5. You should add another row above the first and add full width sheets as far as possible and cut the last sheet to fit. Nail the deck to fit and continue to add the rows then measure and cut the sheets to fill out the top row before you begin to screw down metal roofing.
6. The metal roofing sheets should be positioned at the starting at the lower left corner and attach the metal with a 1-1/2 self-tapping, sheet metal screws. For every 12 inches, use a metal screw and screw down metal roofing.
7. The next sheet should overlap the right side edge till the bottom end with the bottom edge of the roof deck. The overlapping sheets should be pressed down firmly so the standing seams are locked in place, the second sheet should be screwed in place and cut the edge with a blade or saw.
8. Full width sheets should be added all over the roof and screw it in place and then cut the last sheet. Make sure the upper rows are overlapped with the first and continue to add full height rows. Make sure when you screw down metal roofing it remains in place for a sturdy roof.