![]() You still need the ASCE 7 to get the figures and graphs although UK4x4 posted one of them here. I set up a spreadsheet to run all the calcs here: (let me know if you want me to e-mail it to you if it doesn't download). ![]() ![]() I found a copy of the ASCE section 7 (or whatever it is called as referenced in the code) for calculating the snow load. I just went through this for my ongoing design of my cabin. I've always understood the span to be measured horizontally between points of bearing, not bracing. I do think the span reduction you took is incorrect if I'm understanding right. I'd rather reduce spans than reduce loads and strength. ![]() Might someone over the life of the structure install a porch roof? on the lee side? What's around the building? Go carefully when reducing loads. Over the life of the structure, at some point, might the load stick up there? I've seen vertical ice. How in the world? Well, thought I, it happens. He had 3' of consolidated ice and snow on it and an ice dam going on. We had built a 12/12 metal clad roof with 2x12's 12" on center. I quit trying to reduce the ground load after I got a phone call from Terry Peak in the Black Hills. The local Nautilus plant had a roof collapse, that broke the gas line, which then caught fire. In that snow storm we had several collapses. My home has exceeded design wind and snow loads as have several I have built, it's a best guess remember, that door swings both ways. Yup, it's a best guess based on past experience. Design is for resisting a maximum load that might occur at any time in the service life of the building. I'd never seen anything like it in the Sierras!Īnyway, I'm sure the engineering calcs assume stuff like this, but it was certainly counter to my intuition on snow build-up.ĭo think about it carefully before reducing the ground snow load. Even after we'd been in the cabin for two days with the fire roaring it still stuck to the roof, forming vertical snow waterfalls at the edge, hanging down to the mid point of our windows. And then the snow stuck to everything like glue for a two-week cold spell, including our roof and the trees. That was until a few weeks back when apparently it rained, then the temp dropped and it started to snow just as the rain froze. But for the last few year it seemed complete overkill as the roof never held more than a few inches of snow, and at most for a day or two (less if we had the fire going). ![]() We didn't get to reduce the ground snow load for reasons I can't quite remember (but that didn't bother me as our official snow load was probably low anyway and I didn't mind the extra margin). Neither SFPA, nor its members, have knowledge of the quality of materials, workmanship or construction methods used on any construction project and, accordingly, do not warrant the technical data, design, or performance of the lumber in completed structures.We've got a 12:12 standing seam metal roof. The conditions under which lumber is used in construction may vary widely, as does the quality of workmanship. The design values contained herein are based on the Southern Pine Inspection Bureau’s Standard Grading Rules for Southern Pine Lumber (2002 edition with supplements) and modified as required by AWC’s National Design Specification® (NDS®) for Wood Construction (2012 edition).Īccordingly, SFPA does not warrant that the design values on which the span tables for Southern Pine lumber contained herein are based are correct, and specifically disclaims any liability for injury or damage resulting from the use of such span tables. SFPA does not grade or test lumber, and accordingly, does not assign design values to Southern Pine lumber. The maximum spans provided herein were determined on the same basis as those in the code-recognized Span Tables for Joists and Rafters(2012 edition) and Wood Structural Design Data (1986 with 1992 revisions), both published by the American Wood Council (AWC). The primary purpose of this publication is to provide a convenient reference for joist and rafter spans for specific grades of Southern Pine lumber.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |