subject: How To Build A Roof? [print this page] Building a roof can be quite a task, however, with a little know-how it can be done. Here are a few tips on getting it done.
Required Tools:
Saw
Tape measure
Nail gun/hammer
Required Materials:
2'x8' lumber
Nails
2'x4' rafters
Roof noggings/blockings
4'x8' plywood sheets
Roof purlins
Roof sheathing
Roof underlay
Barge board
Fascia board
Corrugated roofing iron
Ridge capping
Barge flashing
Instructions
Cut your beam supports with a saw and use the nails and hammer to affix them to the front and back walls. Then measure and cut the roof beam to the required length out of the 2x8 lumber and nail it in position on top the of the beam supports. Then cut the 2x4 rafters to the necessary length and attach them to the roof beam.
Then cut more rafters to go between the end rafters along the roof (intermediate rafters) and nail them in place 2 feet apart. You will need to cut a nook called a 'bird's mouth' in each of the rafters. If you are not certain how to do this look it up on the internet to see how it is done. Then cut 4 rows of noggings to put between the rafters; put the rows on each side of the wall's top plates so that the exterior boards and battens will have something to sit into.
Cover the rafters with the plywood, driving in nails no more than 8 inches apart; cover the roof entirely from the roof beam to the end of the rafters. Then nail the roof purlins horizontally across the plywood, overhanging each end of the roof by 1 inch. There should be at least 3 rows of purlins. The bottom row of purlins must be flush with the ends of the rafters, a middle row and a top row close to the roof beam. Nail the ends of the roof sheathing to the bottom purlins from below.
Next nail the barge board to the end of the purlins and flush with the top of the purlins. Join the barge boards at the apex of the roof and cut the lower end 6 inches past the rafters. Attach the fascia board between the barge boards and to the rafter ends and then cover the roof with self-supporting underlay.
Then comes the corrugated roofing iron; fix the roofing iron to the purlins with nails or screws, putting nails/screws into the top and bottom purlins at every second corrugation and driving nails into the intermediate rafters at every 3rd or 4th corrugation.
Install the ridge capping and then the barge flashing. The barge flashing goes under the top of the ridge capping. Affix the barge flashing to each purlin and to the barge board.
Tips
All joins running parallel with the rafters should be on a rafter. Any required join running parallel with the Roof Beam, needs to be under a Purlin.
The roofing should overhang the fascia board by 2.5 inches.
