I have a large shed with 6" x 3" timber uprights resting on a stub block
wall. The bottom 2-3 feet of the posts is rotten so I want to splice-in
some new timber. I can't think how to cut a decent lap joint in the
bottom end of the remaining upright so I'm tempted to butt join the
timber and add steel plates (fish plates?) on each side - at a guess
these would be around 150 wide 450 long and a few mm thick.
Suggestions welcomed for how to cut a lap joint on the bottom of a bit
of timber that's waggling in the breeze, or for a source of suitable
Tough to do with the timber hanging down from the roof structure, which
it will be once I saw off the rotten bit. I suppose I could cut a sort
of half lap joint (zillions of half-depth cuts with a circ saw, then
cleaned-up with a chisel) while the rotten bit is still attached and
providing a little bit of anchorage, then saw off the end. Hmm, perhaps
I could first attach some sacrificial timber over the rot and fix it to
the wall to a provide temporary anchorage.
On 24/07/2018 16:42, email@example.com wrote:
I was assuming you have a circ saw with a 3 inch cut, that lets you cut
a lap either 6 inches wide and 1.5 inches deep, or 3 inches wide and 3
inches deep although I would do the longitudinal cut from both sides in
each case. The devil is in the detail of access and how much support
remains from the rotten bit. As you say, temporary supports are another
The alternative butt joint that you describe will not be very strong in
bending. If one (or two) sides of the shed are supported against a wall
then this could provide bracing against wind loads so that the uprights
are just in compression.
The circ saw might not manage 3" depth but I was talking about using
1.5" cross cuts (like a narrow dado cutter) to create a half housing and
avoid having to try to cut vertically up a waggling piece of wood with a
It's not the preferred solution, but should be OK if I can find long
galvanized plates to sandwich the joint.
On 24/07/2018 18:57, firstname.lastname@example.org wrote:
Understood, that would work and not be too slow. The little slices of
wood left behind should snap off near the base, leaving not too much
cleaning up to do with a chisel. You could also clean up with a sanding
disk in an angle grinder.
How visible is it going to be? Another option might be to run a length
of dexion up each corner. Maybe 15 inches long, held in place with
suitable coach screws. Does it really have to be galvanized?
To make a lap joint you can take a quarter out first and then take the
next quarter out. Assuming you have access to one corner and most of one
Its easy with a multitool if a bit slow. You need less access than with
a circular saw or a hand saw.
Maybe one of those little chain saws in the other thread would do it better?
Bit of care with a decent handsaw? 3" with a jigsaw is tricky.
I would strengthen by screwing on some 25x50mm folded galvanised steel
(because I have some:-) but 1"x2" angle would do. Use two lengths per
Alternatively the agricultural approach... butt join and then strengthen
by nailing on 3"x2" either side:-)
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