The 20x40' polebarn carport I'm enclosing is supported with 6x6 posts at corners and rougly every 10 feet lengthwise (10 posts total). I want the siding to match the house (plywood with vertical cedar lapping at studs). I'm having trouble coming up with a solution for how much the siding should overlap the posts. The solution on the house (which does not have the posts) was that the corners were lapped with 1x4 and 1x3 cedar boards. Doing this on the carport leaves 2 inches that needs to be covered by siding on the posts, so if I butt the siding to the corner boards I come up short of the last stud for the first panel. Same thing at the other end. Of course I have a similar problem siding between the non-corner posts, where the panels should butt in the center.

How would a pro solve this? I'm thinking I need to cut the siding to span only 3 studs on either side in from each post?

 

I've read your post several times and "think" I understand your problem. I'm guessing you have studs placed in between your 6x6's, and that the exterior of your stud walls line up with the exterior of the 6x6's?

If so, the layout of the studs on your exterior walls should have been laid out with your siding in mind. So if you would like to start with a full sheet at the corner, your studs should have been laid out with that in mind... 16" OC all the way across the length of the building... ignoring the spacing of your 6x6 posts completely.

As you go around a corner, you usually will pick one corner (like the right side) and start your 16" OC layout from there.

 

I know what you mean - I'm not sure I understand it myself sometimes.

But yes, the outside of the posts will line up with the outside of the wall studs so the siding can use the posts as if they were just another stud. The problem is that with a full vertical plywood sheet and 16" OC spacing, I can only have 3/4" of siding overlap the first post. This leaves 4-3/4" of post without siding. The cedar trim takes up 2-1/2" of the outside corner of the post, leaving 1-1/4" of post uncovered.

Since a full vertial sheet spans four studs OC, if I shift the siding over to butt the post trim, I lose the 16" spacing - that is, I fall 1-1/4" short of the fourth stud (if I count the post as the first stud, since that's where the siding will be nailed).

The question is whether I should modify the stud spacing to coincide with the end of the sheet, or cut the plywood off to fall in the center of the fourth stud, or trim the corners differently - or of course whether any of this makes any difference to anyone but me! Cutting the plywood, I could preserve stud spacing all the way across, although I might have to trim the last panel also. On the other hand it will waste some plywood.

I think I said all that right . . . Bottom line is I don't think 16" all the way across works unless I trim the siding, unless I only overlap the posts by 3/4", so if I do that I have to figure out another way to trim at the corners.

 

Whichever makes the least amount of scrap and the least amount of seams. Typically, a "professional" will use more material if it saves him time and labor elsewhere, or in order to produce less seams. Ending up with some scraps is usually unavoidable. But if you need to rip your first piece in order to get on your 16" OC layout, then that's what you do. The scrap can often be ripped again to start your layout at your next corner.

And are you installing the corner boards first, and butting the siding up to them? Because you could also install all the siding clear to the corner, and then nail the 1x3 and 1x4 corner boards on TOP of the siding. A little faster, requires less precision, and the joint is not as likely to leak.

 

That last is a great idea. The siding edges will also be covered by the corner boards, so they're less exposed than they would be if butted to the boards. (Other seams will be covered by vertical boards).

Thanks for your interest. It must have been painful to read!

 

glad to help. Yeah I know what you mean...it's hard to explain things in writing sometimes.