Wood Purlin Flat Roof

Then i plan on using a double 2 10 for a header and spacing my trusses every 4 feet.

Wood purlin flat roof.

Roof ceiling framing general roofs 3 12 members supporting joists and rafters designed as beams notches holes controlled joists rafters supported laterally a few general comments here about the irc requirements. Flat use factor c fu 1 nds supplement table 4a c i. Roof live load roof dead load x spacing x span of purlin 2. The purlin are ultimately used to fasten the roof steel providing a diaphragm effect along with the siding when properly engineered and installed.

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. Or less x 1 1 cfu the flat use factor for applying the load to the wide face of a member. Do all roofing projects require purlins. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to.

Snap a chalk line horizontally across the roof two feet down from the top. I did not know. One on the post and the next on the header. 2 are indicated below.

Lay the first purlin at the ridge of the roof down to the chalk line beginning at either corner. The inspector asked about the type of wood being used as purlins. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no. Well in most log homes because of the popularity of high ceilings in great rooms and the lack of attics the ceiling is also the roof.

Roof purlin are members used to directly support roof sheeting materials and could be made of timber or steel. The roof support system is a ridgepole and either rafters which run perpendicular from the top of the walls to the ridge or purlins which run parallel to the ridge. 1 ft 0 3048 m. I have extra wood so i did plan on adding a short chunk of 2 4 on trusses where the purlins meet on the single board.

For relatively flat roofs slope less than 3 12 the joists and rafters have to be designed as beams. Live load is weight of furniture wind snow and more. 8 x section modulus of a 4 2 of 1 3125 x fb fiberstress in bending x 1 15 duration of load x 1 15 cr repetitive member factor as the purlins are spaced 24 o c. Fasten the purlin with 16d common nails into each vertical rafter.

1 psf lb f ft 2 47 88 n m 2. Insert two equally spaced nails into the rafter. In timber construction purlins are nailed to the rafter or supporting trusses while in steel roof construction they are welded or bolted to the rafters or trusses by the means of cleats. Dead load weight of structure and fixed loads 15 lbs ft 2.

He gave me a copy of r802 5 1 3 rafter spans for common lumber species.