I’m in the process of building a deck. It’s a relatively simple design, 16’x8’, which fits into an inside “L” in the back of the house, so one 16’ and one 8’ are attached to the house. Along the remaining 16’ side will be a beam and a series of 4x4 or 6x6 posts. I have not decided yet. In the future, to area will be enclosed, and become part of the new kitchen.
I hope to be able to explain this in words. In the back of the house where this deck is going, the basement on one side of the “L” is a walk-out, while on the other side the basement wall is about 4’ under the ground. Several retaining walls form a basement-level patio for the walkout side, and one of these walls is basically parallel to, and directly below, where my supporting beam for the deck would be. This retaining wall is 4’ high, 12” thick, consisting of 6” cinderblock and 6’ of stone, and capped with flagstone. The walls have been there since probably the 60’s, with no signs of cracking, shifting, or settling.
Here’s my dilemma: If I could simply attach posts to the top of the one parallel retaining wall, I would not have to dig any holes, or at least not as many. But, I do not know how to attach the posts to the top of the wall. The flagstone caps are loose and can be removed, and underneath you can see toe cinderblock/stone makeup of the wall. Again, it’s very solid, and the township seems okay with the idea so long as I work out the attachment issue. To that end they were less than helpful.
I thought about adding some courses of new block on top, but I would rather keep the area open. In addition, my a/c unit is in this corner, and I don’t want to move it until this area becomes an enclosed part of the house. To add strength, I may add re-bar to some of the hollow portions of the cinderblock, then fill with concrete. I guess I could also add some foundation bolts.