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Discussion Starter #1
Hello :)

The Project:
I have a gas powered pottery kiln outside, and am looking to put a corrugated roof over it.
Area for roof is 7.5'x6.5' and will be a height of 6'.

My plan is to put 4x vertical corner posts (3"x3") 2' in concrete and 6' visible.
Then; 4x horizontal posts (3x3") to join each corner post at their tops.

I have a single angle iron which will be the mid-way rafter as this will be directly over the heat source.

My dilemma (being a complete bodger) is what would be the best way to join the 3-way joint at each top corner ?

I had thought about using a half lap joint to join the vertical post to the horizontal 'width' posts, secure with a couple of coach bolts.

Then secure the other 2 horizontals ('depth') to the width posts, but not at the corners, slightly inset by say 4 or 5 inches
Guess i was thinking that if i could avoid 3 posts joining in one place .. would be stronger and easier !!

I've put the worlds BEST diagram up as atachment ... no, I haven't got a drawing tablet or scanner or camera handy .. sorry, at least it'll give you a laugh.

Phough ... well that's me.
Any comments, advice or suggestion welcome.
My main conern is wind .. I have no idea what forces a wind catching the roof would put on these joints.
 

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Old School
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Hello :)

The Project:
I have a gas powered pottery kiln outside, and am looking to put a corrugated roof over it.
Area for roof is 7.5'x6.5' and will be a height of 6'.

My plan is to put 4x vertical corner posts (3"x3") 2' in concrete and 6' visible.
Then; 4x horizontal posts (3x3") to join each corner post at their tops.

I have a single angle iron which will be the mid-way rafter as this will be directly over the heat source.

My dilemma (being a complete bodger) is what would be the best way to join the 3-way joint at each top corner ?

I had thought about using a half lap joint to join the vertical post to the horizontal 'width' posts, secure with a couple of coach bolts.

Then secure the other 2 horizontals ('depth') to the width posts, but not at the corners, slightly inset by say 4 or 5 inches
Guess i was thinking that if i could avoid 3 posts joining in one place .. would be stronger and easier !!

I've put the worlds BEST diagram up as atachment ... no, I haven't got a drawing tablet or scanner or camera handy .. sorry, at least it'll give you a laugh.

Phough ... well that's me.
Any comments, advice or suggestion welcome.
My main conern is wind .. I have no idea what forces a wind catching the roof would put on these joints.
Why not just half lap the horizontals over a corner post, and then lag it to the post.








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Discussion Starter #3
Your mean: top of post, then 1 horizontal lagged into it from above, then the 2nd horizontal ontop of that ?

I guess i thought that that'd mean a lot of lag screws all in one place, and assumed that the more metal there was, the less wood .. so would I compromise strength ?

Guess that leads me into another question, and excuse me if it sounds dumb (but I am !)...
When not glueing, does a half lap joint not reduce strength in the timbers ?
After all, I'm starting out with 3" of timber, and reducing it to 1.5" .
Would a stright plain butt joint not be stronger ? Or does the length of coach bolt come into the equation ???

... see I'm confusing myself now :(
 

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Old School
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Your mean: top of post, then 1 horizontal lagged into it from above, then the 2nd horizontal ontop of that ?

I guess i thought that that'd mean a lot of lag screws all in one place, and assumed that the more metal there was, the less wood .. so would I compromise strength ?

Guess that leads me into another question, and excuse me if it sounds dumb (but I am !)...
When not glueing, does a half lap joint not reduce strength in the timbers ?
After all, I'm starting out with 3" of timber, and reducing it to 1.5" .
Would a stright plain butt joint not be stronger ? Or does the length of coach bolt come into the equation ???

... see I'm confusing myself now :(
You half lap the horizontals together to form a 90 degree corner. You will then have a 3"x3" corner assembly. Then lag that to the top of the post with two (maximum 3). You could use a resorcinol glue (phenol-formaldehyde).

You could half lap the two horizontals and then drill through both into the top of the post with a 1" dowel, and install with glue. Lags could also be used.

You could also cut out a 1/4" deep section (3"x3") on the bottom horizontal connection to sit on top of the post...giving two shoulders to the post.

Gussets at the underside corners will prevent racking and give it strength.








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Discussion Starter #5
Many Thanks CabinetMan.

I guess I've overlooked the obvious !

And an additional bonus .. a saving on lags ;)

Thanks for your help :)
 

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kinda like that dowel idea. i normally do 4 uprights and 2x6s running for the horozontal arts screwed to the face of the post at the top w/ about 6 16D nails or 20D nails in each end. i try to use 6x6s or even used telephone poles if i can afford them.
 
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