Timber Framers Guild

length of braces

Posted By: GeorgeTaylor

length of braces - 12/19/12 10:47 PM

Hello again,

If I was to build a 4-bent 25'x25' barn (top plate 14' high) as pictured on page 3 of Sobon's HISTORIC AMERICAN TIMBER JOINERY then what is a good brace length? The tie beam is below the plate. Barn timbers will be white pine and the shouldered braces will be oak.

In some timberframe design books, I see diagonal brace lengths of 45.25" (49.25" including length of tenon). But, in some old existing barns, I see longer brace lengths of maybe about 5,6,7 feet.

Is a brace length of 45.25" too short?

Thanks
Posted By: TIMBEAL

Re: length of braces - 12/19/12 11:28 PM

That is a 32 inch leg, yes short in my opinion. Make them as long as you can get away with. Depending on bent spacing, door, windows etc., will limit brace length.

On page 41 there is an example of a similar barn where the brace legs are pushed down to the girt with a potential shared mortice.
Posted By: Roger W Nair

Re: length of braces - 12/20/12 02:08 AM

I would favor much longer braces, how long, anywhere from one third post length to sill to plate. I also see no requirement that the braces be flush to outside surface so the wall purlins can bypass the braces and then spike or quarter lap purlins to braces.
Posted By: GeorgeTaylor

Re: length of braces - 12/21/12 04:23 PM

Thanks for the responses.

I have already rough cut about 10 braces with legs of 32" (45.25" diagonal). But have many more to cut.

If you look at the barn I mentioned in the original post (page 3 of Sobon's book), do think I could use these shorter 32" leg braces for the smaller bents (2nd floor) that support the purlin plates? And then cut longer 36" leg braces (about 50.9" diagonal) for the main bents on the 1st floor?
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