MCA pressure treated 4x6 corner join question

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Forum topic by Charlie posted 04-24-2013 03:34 PM 4136 views 0 times favorited 6 replies Add to Favorites Watch
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1101 posts in 2892 days

04-24-2013 03:34 PM

Topic tags/keywords: question

I have to make a 12’ x 10’ frame out of MCA pressure treated 4×6 standing “on edge” (4” side is bottom and top)

I want to keep the corners together pretty well. Should I half-lap them and put a stainless steel lag in them?
Half-lap and drill through and drive a 1/2” rebar? (concerned about simply corroding the rebar on that one)

The frame is basically a foundation for a garden shed that will get a crushed stone floor, later to be covered with concrete pavers. So the corners will also have walls standing on them, the bottom plate of which can act as a tie plate, This will all be sitting on a bed of compacted gravel about 8 inches deep and the PT 4×6s will be above grade so I think they’ll last as they’ll never be in contact with dirt, but I really want to have a decently tight corner.

I was also thinking of “painting” the lap joint with roofing cement because of the cuts.

and before you ask, no, I can’t just do this like a pole barn because I can get holes anywhere near deep enough due to tree root and big boulders in the ground. I can only get down about 1 to 2 feet more than the 4 inches I’ve already excavated for gravel. And the quote for a concrete pad for this was $825 (due to it being a small job and affected by minimum trucking charges, etc).

6 replies so far

View crank49's profile


4032 posts in 3577 days

#1 posted 04-24-2013 03:49 PM

I don’t see why you couldn’t half lap and drive a couple of hex head, corrosion resistant, “Spax” screws in each joint.

View Charlie's profile


1101 posts in 2892 days

#2 posted 04-24-2013 03:53 PM

Forgot about Spax, and I have some in the shop. I don’t remember anything about corrosion resistance on them but I can look. Might also be a few different kinds/coatings or something.

View Lee Barker's profile

Lee Barker

2172 posts in 3456 days

#3 posted 04-24-2013 04:12 PM

I’d be conscious of the inability of end grain to hold threaded fasteners.

Do you have access to a metal scrapyard? I see angle iron lengths, drilled for lags.

You might look at the Simpson joist hanger stuff. They make some galvanized angle brackets that would be appropriate for the inside of that butt joint. There are also strapping products that could be cut to length, bent at 90o and affixed to the outside of the joint.



-- " his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

View Charlie's profile


1101 posts in 2892 days

#4 posted 04-24-2013 04:18 PM

Lee, the reason for the half lap would be so I’m not going into end grain. But you’re right about the Simpson stuff. I’m pretty sure they have an inside corner bracket

thanks for the input. Appreciated

View Marty5965's profile


161 posts in 2552 days

#5 posted 04-24-2013 04:25 PM

Yep, they do, I used their hangars on my Deck frame (see projects). I would seal the ends with something but a half lap and hangars should hold up well.

-- Marty, Wilmington, OH, learning every day....

View Charlie's profile


1101 posts in 2892 days

#6 posted 04-24-2013 04:48 PM

Sealing the ends: yeah. I plan on it. Not sure of method yet as I have to consider aesthetics. Might be a matter of tagging a couple scraps of ice and water shield on it or painting it with roof cement and then making like a corner board out of PT 1×4 or something. With the idea that the PT 1×4 is sacrificial :)

Wife wants board and batton and wants it painted (think cottage) so I’m going to run 2×4s horizontally on the outside of the stud wall to attach the b&b. This will also keep drips off of the ends of the 4×6s.

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