Thirdly, purlins add additional support between the spans of the individual framing bays. Secondly, purlins tie the rafters together, stabilizing and strengthening the structure’s rigid framing. Using Truss bottom chords for Storage is not a good practice. Metal building roof purlins provide three structural functions: First, the purlins support the roof. Attach the Purlins to the Truss using 60penny Ring Shank Nails thru the Purlin into the Truss and then angle nail a 16 Penny Ring Shank Nail on either side in a toe nail fashion.This is not a good Roof Structure for a Plywood and Shingle Decking nor is it a good base for an Insulation and Ceiling situation. The size of the drill bit should be slightly smaller than the screws or pins you will use. This will ensure that the screws or nails go in smoothly and securely. The tails of the Purlins should be soundly attached to the neighboring Purlin. Using a drill with the appropriate drill bit, pre-drill holes where you have marked for purlin placement. Common spacing for trusses on this type of building is often between 2 and 4 feet, but trusses built with advanced designs may allow spacing as great as 8 or 12 feet. The same concept holds true for roof trusses. I saw had Trusses and Poles 3'3" O.C.and 2"圆" SPF Lumber on 20" Centers.My feelings at the time considering the cost and the Construction requirements were that the customer would have been served better if he had been sold a Steel Bldg.In your case I still would recommend a 7'6" Pole and Truss Spacing and SPF 2"x4"x10' Purlin spacing on 24"O.C. So the space between rafters can be greater without reducing the maximum span. Remember that your Roof Steel adds to the Snow Load Capacity of the Roof.Extreme Snow Load areas have to be Engineer Approved and ,although I never erected one the one Extreme Snow load Bldg. Securely nailing the Tails of the Purlins to each other where they overlap is part of the "Snow Load" equation. for a 7'6" Truss spacing using SPF 2"X 4"X10'Lumber. Re: Purlin size for pole shed in reply to Nick R (Wi), 06-04-2006 05:15:03Īs a former "Astro Pole Bldg" Dealer and Contractor I will offer that Astro Spec's are 24" O.C.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |