Greetings! I am planning to build a 16'W x 10'L walkout level, freestanding deck with a pergola spanning the entire width/length of the structure. Currently, I plan to extend the 6x6 posts through the deck to serve as the pergola posts. Ideally, the posts situated closest to the house will be within 3-4" of the house wall after taking the rim joist and a gap for expansion/contraction into consideration.

My problem is that AWC code requires a 20" diameter footing, which puts the center of the 6x6 posts 10" from the house wall (= 7" gap from the post to the wall). I've seen photos of other freestanding decks that seem to overcome this issue, but I am curious how to go about minimizing that gap. I also plan to enclose the pergola sides with a privacy wall, so having the posts close to the house will make the privacy wall more aesthetic and effective.

My first thought is I could just use different posts for the pergola, but I'm not sure how to go about securing the pergola without giving it its own footings, which brings me back to the original question. Simply bolting the pergola posts to the rim joists doesn't seem like a likely option considering the entire pergola would be relying on the shear strength of the connection and support strength of a rim joist.

Lastly, the plan is to use 6x6 posts for the deck support, but if I end up not extending the deck posts through the deck for the pergola, could I use 4x4 posts for the pergola/privacy wall? The pergola would have 7 support posts, one at each corner and another centered on each side besides the house wall. The posts would have the additional support of the privacy wall, so that should help with the rigidity. The pergola will be about 8' tall, and the privacy wall will be 4' tall solid planking and 4' tall lattice all the way around the perimeter.

 

Talk with your building inspection dept. They will advise you as to what footer they will accept. My inspectors have allowed a new footer to be poured right up against the house's footer. They had no problem with posts being off center next to a house.

 

Post footers close to the house will most likely be built on back-fill soil, rather than undisturbed soil. I suggest moving far enough away from the house to build on undisturbed soil and use cantilevered joists.

Does your house have an overhanging roof, and if so. will this be a factor to consider when adding the pergola?

 

I am digging below the house's foundation to place the footings so that they will rest on undisturbed soil.

Yes the house has an overhang at 9', whereas I only plan to have the pergola up to 8'.

 

Something like this would be ideal