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Check out this view of the deck floor while coming up the stairs. It kind of reminds of Galloping Gertie!
This is me waving to you from my deck! It was bank-owned and unfinished when we purchased this house. The contractor had some guys install the deck, it wasn’t level when we moved in. It was obvious that the slope was downwards.
However over the last 8 1/2 years it has gotten.
The deck guys didn’t install stairs either, so I installed some about 6 years ago. I should’ve fixed the slope then, but didn’t. I installed the stairs level, you can see the deck slope.
Now to see how level the deck is. Yep just what I thought, it’s not level, the bubble is over on the far right side.
From what I’ve read, a deck without gaps in the flooring should slope about 1/4″ over 12′ to allow for watershed. Decking with gaps doesn’t require the watershed angle. I guesstimate my deck is sloping a few inches over 12′.
Fix the Sagging Deck – The Game Plan
The plan is to jack up the deck and replace the 6×6 deck posts with posts that are the correct length.
Supplies Needed:
- 3 – 6″ x 6″ posts (actually 5 1/2″ x 5 1/2″)
- Nails
- 4′ level – it is useful to have multiple levels
- 6 – 4 ton bottle jacks (I bought Black Bull but they seem to be out of stock) I wanted to put 2 on either side of each post.
- 6 – 4×4 posts (to support bottle jacks)
- scrap 2×4’s
- Reciprocating saw + Battery
- Wood and Nail reciprocating saw blades
- Hammer
- Circular Saw
- Impact Driver (to remove deck wrap/facing)
- Square
- Pry bar
- 2 1/2″ screws
First I used an impact driver to remove the deck wrapping (treks). The Ridgid is an indispensable tool. I love that Ridgid has 3 torque settings on the impact, it makes a huge difference in applications like working with treks!
Now to set up the jacks. I placed 2 jacks next to each deck post (3 posts + 2 jacks = 6). I got some 4×4 posts and screwed on some scrap 2×4 to the bottom to make a T and leveled out the ground as needed. To distribute the jack load on the main beam that is laminated, I attached more scrap 2×4. Then I leveled the posts and pumped up the jacks to be taut.
Now the jacks can be used.
Then I cut the bottom of the existing deck posts to be free. Some of the nails came out easily with a hammer and pry bar, others I used the wood and nail Diablo blades with the Makita reciprocating saw. This recip saw is part of Makita’s sub compact line. I really like the smaller body 12 1/2″ long, but it still has plenty of power! It’s variable speed too, depending on how far you pull the trigger.
I also detached the stairs from the deck.
Time for the excitement, jacking up the deck. I started on one end and gave each jack a pump going down the line, and repeated pumps in order until the deck started to become level. The farthest corner was the first to be level. It only needed to come up about 2 1/2″ (I put a 2×4 in the gap for comparison).
I detached the top of the post with the reciprocating saw, cutting through the nails. Did I mention how much I love the Diablo wood and nail blades, they are fantastic.
I measured from the saddle to the main deck beam to get the new deck post length, and cut the post to length with a circular saw.
I slid the post into place and made sure it was level. Then attached the strap and footing bracket to the post, also toe nailing a few nails into the deck beam for good measure. After I installed the first post, I moved the jacks down to the other corner of the deck to provide more support.
The center post was next to get level, the gap on that post and the last corner post was a whopping 4″! I repeated the same process to replace the center and corner post.
Now we are level! You can see a small wave over by the blue bench, I need to adjust a couple of the joists that were mounted a little low. Overall I’m thrilled though.
It’s time to reattach those stairs!
Now you can add patio decor. This swing is great! 
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