A customer of mine wants me to build a free standing deck approx. 14′ x 14′. The deck will be up tight to the house on one side and will be about 11′ from grade to the floor system. Using 6×6 posts, does anyone have suggestions for the best way to anchor this thing to the ground so it won’t be wobbly and wiggly.
I will use 4×4 or 6×6 45 degree braces bolted between the band and the posts. If the posts were anchored to good, solid footings using Simpson post bases would that be enough? Does code specify any requirements for this?(Too lazy to look it up myself this late at night.)
I’m not a big fan of burying the posts deep in concrete or the ground for that matter because we all know they will probably eventually rot. I live in a relatively wet climate so I don’t want to take any chances with that.
As for the reason we don’t want to bolt it to the house, it’s because it is an old stucco house and we are trying to avoid penetrating it which would require cutting out stucco, flashing, patching that probably wouldn’t match, etc.
Replies
I'm no engineer, but it seems to me that by avoiding tying this deck to an existing anchor (i.e. the house it would be part of) you create the need for a lot of extra support to keep it stationary.
In addition to the shear members you will need (the 45 deg. braces), the structure would also need horizontal cross bracing to keep it from twisting. At 11 feet a "live load" can exert a lot of pressure on a plane like that.
I don't understand why attaching a ledger to the house need be such a major production. While it's true that the best way would be z flashing from under the stucco, can't you just use galvy lags and spacers to hold the deck against the rim joist without disturbing additional stucco? Just fill the holes with plenty of Sikaflex and angle the lags slightly down to insure drainage. If the deck will be free standing anyway, you won't have to worry about bearing weight and it will save you a lot of time and materials with cross bracing. Just my opinion.