The Forestry Forum
General Forestry => Timber Framing/Log construction => Topic started by: OffGrid973 on October 19, 2020, 06:38:26 PM
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Hi Guys,
Just got my first two 10"x10" white oak post cut and waiting on my third. I have 10" wide braces cut for the 45s, what width do I want them. 3.5" ok structurally? Now if yes, how strange will 3.5" width look in reality? Putting two similar entrances into front side of my barn, replacing what was lap siding 20' long.
If I get a solid 20' (10" wide but lam beam concept so I can lift it) then I will put that all the way across...if not two 10' with some kind of lapping joint, open to any ideas.
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I don't like any brace stock less than 4" thick. It doesn't hurt anything to go thicker either, if it fits in with the rest of your design. That is, as long as it doesn't interfere with doors or overhead tracks etc. Using a 10" post, thicker may look better proportionally. Use your artists eye and determine what looks right for you.
Structurally a wooden brace works in compression, it is essentially a column. With that in mind the failure mode in the dimension you are asking about is buckling. The longer it is the thicker it needs to be. As a practical matter the rule of thumb is to never go below l/50 so for a typical brace no thinner than ~1.5". So there you are usually golden. The next is side grain compression of the brace into the post, shooting from the hip ~825 psi in white oak, again probably fine. Now once everything shrinks its a whole other matter as to whether the braces are engaged enough to do real bracing work.
The members of the beam should to run from post to post, no lapping in span. I sort of doubt 10" deep is sufficient for a 20' span.
It will belly out/sag as it dries at that 20' span and look not so great while it also pulls away from it's end bearing points?
However, (it's big one IMO) based on your title which states 10' beams not 20' as does the text, lets be sure your not doing typos? :D
Pictures don't "look like" 20'???