Timber Framers Guild

splicing in patches on posts

Posted By: Anonymous

splicing in patches on posts - 03/22/01 01:00 AM

I attended the recent gathering at the Frontier Museum in Staunton Va. I had a great time but I saw a patch job on the german barn that I just don't understand. I figure you guys can explain it to me. Where the bottom of the post was rotted they cut off a section and patched in a piece that resembled a scarf joint. It seems to me that a wedge patch pointing up would tend to split the wood above it not support it. I've seen this kind of patchwork before and it sure looks pretty but is this the best way to strech a vertical timber?
Posted By: Rudy R Christian

Re: splicing in patches on posts - 03/23/01 09:34 PM

Unfortunately I didn't see the post repair you are referring to. I am assuming that your reference to a "wedge patch" indicates that the scarf had sloped faces on the blades. This is referred to as a "splayed" scarf. The end of the blades typically ends ay an abutment cut from the blade to the face of the timber. A simple splayed scarf with square or undersquinted (undercut) abutments is commonly used in horizontal timbers such as plates or ties. Rarely have I seen it used in post bottom repairs.

A modification to this scarf joint is known as a "scissor" scarf which has two blades, each cut halfway through the timber and with opposing slopes. I have seen this scarf used in post repairs and it appears to work quite well.

Can you describe the "wedge" condition more clearly?
Posted By: Anonymous

Re: splicing in patches on posts - 03/25/01 02:58 PM

Thanks for the response. I'll try to make my self more clear. I suppose I shouldn't have used the term "scarf" but I was close when I said wedge. On this particular patch the outside three inches of the six by six post was removed about a foot or so up. Instead of a rectangular piece patched in they angled the top of the patch at a geater than 45 degree angle sort of like a dovetail notch on a log cabin. I'm sure this would cause the patch to stay put but it seems that any bearing weight above the patch would tend to be pushed outward...thus causing a split to start. I wish I could draw this out... maybe I'll see you at the next event and you could explain to me why this would be better than a plain old rectangular piece.
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