Thread: compound mitre angles

Hi drphoto, welcome to the forums.

Could you post the sketch-up or a diagram of what you're describing? That should help understand the challenge.

Cheers,
Af.

if you cut each post to the correct angle before installation you have to get them all the "right" length and orientation — no easy task

I suggest it would be easier to install all the posts over length by say 50mm and then use two or more string lines to mark the angles required directly onto each post.

i hope the file has attatched and it is openable. They are pdfs so they should open ok, and thanks

Looking at the file axo 01.pdf
I suggest that you lay each wall out full scale on the floor or slab and build the frame horizontal before standing each section up. Then it's relatively simple to scribe each post with the correct angle on adjacent faces – then cut
Normally rafters would be notched to fit the top plate — you wouldn't try to angle the top plate so taht the rafters don't require notching.

Thanks, I have been building the shorter rear zig zag walls flat and lifting them as you said, it works well. I got someone around yesturday to look at the the slopes etc. I think we are going to build a low wall from scrap wood and experiment until we get the right slope. We have found a 11.5° slope in one direction and a 2.5° along the length of the wall doing the math. we are going to tap the saw off square for the small angle, and hopefully the joint will look ok, at square there would only be a 2mm gap on the one side of the joint. Thanks again for the advice. I will be probably be back soon with a new dilemma.

Originally Posted by drphoto

the roof angle at 90° to the rear wall is 11.2°(not the final pitch).

so the correct pitch is 20°?.. the roofing for this is surly running parallel with the rafters?

so i would just work off that at the 76.5° angle to the walls, just determine the run at 76.5° to the wall and calculate the rafters to suit, what your saying about cutting the wall posts? im not sure exactly what or how your making this, but the angle will be the same as the pitch of the roof even if the rafters then run 76.5° to it, the rafters will end up being another pitch..

ive done a roof like this before, except the rafters ran 45° to the walls which makes things alot easier.

its hard to see what your trying to figure out.. if there's any calculations you need doing just ask and ill be happy to help

(with more information i could tell you what heights to do the walls and all angles ect)

the pitch is 20% , which is 11.5° off the top of my head. A friend has done a few calculations. They seem to make sense to me so I will build to those and find out in a month when I start placing the roof beams if he was right. I might make a test piece and check it out at ground level just to be sure.Thanks again

hey, sorry you got my curiosity going

the pitch of the roof going 90° off the bottom framing [or what ever was 76.5°] is 11.095° appose to 11.307°/20% which is the rafter line

anyways hope its all going well, and good luck

Luckily I can't measure the angle that accurately, and i feel that 11.1° and 11.3° is the same in my book. They are rafters and not a delicate inlay, a few millimeters here and there shouldn't cause much of a problem. And I think I need all the luck I can get.