Tractor Talk Discussion Board |
Re: OT Max rafter length
[ Expand ] [ View Replies ] [ Add a Reply ] [ Return to Forum ]
Posted by jdemaris on May 17, 2007 at 06:01:26 from (66.218.11.244):
In Reply to: OT Max rafter length posted by John S-B on May 16, 2007 at 20:15:07:
Besides the dimensions of the wood, the type of wood makes a big difference. Years ago, for certain jobs I used to special-order Douglar Fir for long spans and heavy snow loads - but can't get it anymore (here in New York). Next best option is Southern Yellow Pine - since it's usually commonly available in pressure-treated lumber - but costs a lot. I wish I could get it untreated. We get heavy snow loads where I live and 60 lbs. per square foot is the minimum code requirement for most buildings. For a 15' span, if you are using common spruce lumber, 2 X 12s will just barely make code if used on 16" centers. The strongest wood, e.g. Douglas Fir, Southern Yellow Pine, can carry a longer span than weaker wood - e.g. spruce, white pine, red pine, hemlock, etc. In my area - all standard framing lumber comes as spruce - but I am in New York. If I buy rough lumber from a local mill it will be hemlock. If I lived down south - the wood would likely be much stronger as Southern Yellow Pine. 30 lbs. snow load - 16' span - 24" on center - 16 feet max. span - 2 X 10 best wood. If spruce, only 14 feet. 40 lbs. snow load - 14 1/2 foot span max. - 24" on center - 2 x 10 for best wood, 13' for Spruce. I've built several buildings over the years with 20 foot spans using 2 x 12s on 14" centers. That meets the new code regs. and will hold a lot of snow in case I'm not around to shovel it off right away. It's not an issue with most of my 5/12 roofs with steel - but flatter roofs can be a problem. Technically, a 2 x 12 of the strongest wood is rated for a 17 foot span at 60 lbs. of used on 16" centers, and 14 1/2 foot on 24" centers.
Replies:
Home
| Forums
Today's Featured Article -
Chores - by Frank Young. The ceaseless passing of time! It is at once our friend and our enemy. It measures our progress and it makes us old. Like most features of our life, few things are all good or all bad, and most such judgments depend on our own perspective or viewpoint. In our particular hobby, we enjoy the nostalgic return to the days of our youth as we recreate many of the scenes that took place on the family farm that served as the stage for the first few acts of the play that is our live
... [Read Article]
Latest Ad:
Sell 1958 Hi-Altitude Massey Fergerson tractor, original condition. three point hitch pto engine, Runs well, photos available upon request
[More Ads]
Copyright © 1997-2024 Yesterday's Tractor Co. All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V. Yesterday's Tractors - Antique Tractor HeadquartersWebsite Accessibility Policy |
|