Afternoon, folks. I have a deck that I am re-decking. Easy job, until I found that all of the footers were rotted out. The deck is bolted to the house on two sides, and the remainder of the deck is supported by 4×4 posts in concrete footers. The deck varies by between 4" and 12" off the ground, so getting new footers under the beams is not an option. I've had several thoughts:
1. Somehow remove the rotted posts from the concrete footings, fill the void with concrete and anchor a post base in there. Jack up the deck, insert new post, and then lower deck back down.
Problems: Not all posts are fully rotted and removing the remaining 4x4 has
been difficult. I have almost no room to work under the deck due to it being
just a few inches to a foot off the ground, so burning or pulling them out,
even if possible, is not an option. I don't think that I can do this.
2. See "OFFSET1." Dig a new hole, drop in concrete tube and fill to 2" above grade, set post base, attach post, and connect to the beam from the side using carriage bolts.
Problems: I don't think I can get the auger close enough to the beam to be
close enough for this to work. Not enough room to get the auger under the
beam.
3. See "OFFSET2." Dig a new hole as close as I can to the current beam. Drop in concrete tube and fill to 2" above grade, set post base, attach post, sandwich in additional 1×12 to take up remaining distance btween post and existing 1×12 beam, and connect to the beams from the side using carriage bolts.
Problems: Does this put too much strain on the post base?
4. Demolish deck and start over.
Problems: Hell. No.
So that's where I am at the moment. OFFSET2 seems like the only viable option. But I'm concerned about the stress on the post. Maybe if I stagger the offset posts on alternating sides of the beams the stress will be dissipated? What are your thoughts?
Best Answer
You can dig out the old footing where accessible even if means digging an "offset hole" to get it out. place a sonotube back in the hole, 6" above the bottom and fill the tube either 2" above grade for a short post or mount the clip to the deck after the old post is removed and run the concrete up to the clip. Place a wood form in the bottom of the hole if the offset is too much.
To get access to the other holes, remove 4 to 6 decking boards the get access from above, and do more of the same there.
None of it is going to be easy, but it is possible without tearing out the whole deck