Deck footing next to house foundation
I am building a deck adjacent to the back of my house, and I want to keep the height to a minimum. If I use a ledger board, it would have to be attached to the foundation blocks. The problem is that the blocks have a decorative texture that is very coarse. If put a ledger on, there could be gaps as wide as 1/2″ between the ledger and the block. Also, I don’t see anyway that I could flash the ledger. Also, the blocks are not solid, so I am a little concerned about properly anchoring the ledger without damaging the block.
As an alternative, I have considered scrapping the ledger and just digging footers right next to the foundation. However I am not sure if pouring a concrete pier next to my house foundation won’t just cause a different set of problems as water freezes/thaws every year in the gap between the two.
Since the deck is being placed on an inside corner with the house on two sides, simply rotating the direction of the headers is not an option. Any suggestions?
Replies
FYI - Footings must bear on undisturbed ground. You must assume that the earth within 4' of your foundation is disturbed. Therefore you must dig down to the house footing level. Sounds like a lot more work than resolving the block issue.
1/2" space between the ledger and block is fine as long as the thru-bolts have adequate washers and are properly tightened. Thru-bolt to a 2x on the interior side of the blosck wall.
Most decorative blocks are rough faced but maintain an overall uniform peak and valley pattern. Hold up a 2 x 12 x 8' against the block and check out the actual bearing surface pattern.
Flashing can be installed. It will need to be tucked into the block mortar joints though and repointed. Pretty basic stuff.
Hope this helps,
Frankie
from Fear And Loathing In Las Vegas
beams and cantalever the joists
depending on size, could get 2' from foundation
bobl Volo, non valeo
Baloney detecter
Rent yourself an auger, go two ft out as was mentioned and dig your piers. Cantalever to within a 1/2" of the home, you will be fine. This is a common tack in building decks.
I think self-supporting decks are preferable, particularly when low to the ground.
With all of the deck collapse stories in the news, the recommendations for ledger fastener schedules is getting ridiculous....
plus, all of these concerns about fastener corrosion with PT lumber...
plus the complex flashing and sealing required to prevent rot....
Rotten sills where decks attach is super common.
Dig the footings far enough from house for comfort then cantilever the rest.
Self-supporting decks do require extra cross bracing.