House is cabin construction 2x4's. Dirt floor. Main support piers in the center of the house are sunk concrete, but the beams are sagging all over. Center support piers are reasonable.

I used jackposts on concrete blocks between the center support pier and outside wall. The problem was crawlspace was wet so the blocks sunk. I have remedied most of the wet problem.

So the right way to do this is to dig down 2 feet and sink some concrete, then jackposts under the sagging part of the beam. (ok should be wood pier...) I was told only screw the jackpost say 1 inch a week till its level.

Are there alternatives to sinking concrete?

It's rather cold here now and the less I have to be under the house, the better.


  • I don’t understand 1) you say “dirt floor” then say “crawl space is wet”. 2) What is reasonable about center support piers? 3) How large is the house? Is it all sagging? ...sagging uniformly? Is it one story only? 4) Can equipment get inside the house on the dirt floor? 5) Are there pile drivers available? ...vibration piles used in your area? 6) location?
    – Lee Sam
    Jan 20, 2020 at 4:17
  • With the floors sagging jack posts over time is a good idea. If your pier blocks continue setting you need additional ones or larger ones.
    – Ed Beal
    Jan 20, 2020 at 16:54
  • The immediate problem is fix the floor under the woodstove so I can put an airtight stove in. How big / long on 6x6 pressure treated? I was thinking several 2ftx2ft concrete blocks - but that could settle too. I suppose I could screw mount the jackpost to the beam...
    – House DiY
    Jan 21, 2020 at 7:13
  • Can I dig a hole and fill with gravel, then put a paver on top, then the jackpost? 4 foot jackpost at most.
    – House DiY
    Jan 21, 2020 at 15:20
  • Lee Sam - 1) you say “dirt floor” then say “crawl space is wet”. Water was literally streaming down the driveway downhill into the crawl space (with a dirt floor). Mostly fixed now. I dug a trench in front of house. 2) No apparent major sinking and dryer 3) Very small. This beam is 30 feet at most. It is slabbed 2x4. >Is it all sagging? ...sagging uniformly? It sags from the center to the outer side piers on both sides of center support pier >Is it one story only? Yes 4) Unlikely 5) No. 6) Northeast
    – House DiY
    Jan 22, 2020 at 16:30

3 Answers 3


A bed of gravel under 3' 6x6 sleepers or a triple stack of 2x10s should do fine. As Steve Foutz said, you're looking for surface area, and it has to be something that won't flex into a banana under load.

  • How deep of a bed of gravel ? This work is up soon. I would be so good with not digging down on all the sections that need a post.
    – House DiY
    Jun 19, 2020 at 21:47
  • That depends on your soil. Ask around locally.
    – isherwood
    Jun 22, 2020 at 12:53

The Building Code allows for alternate footing designs other than concrete and allows for treated wood piles, steel piers, etc. (See ICC Section 1805)

It even allows for treated wood members but they must be designed for expansive soil conditions, seismic conditions, must be constrained (can’t lay loose on ground), AND must be BELOW ground water conditions.

The reason it must be below ground water conditions is because bugs can’t survive below water.

Some of the other answers suggest using treated wood on the ground or on gravel. These suggestions are for temporary repair ONLY. Ultimately you’ll need concrete footings or treated piles, etc.


I don't think digging a deeper hole into wet ground is going to help you. You need more surface area. I would form and pour a footing two to three times the area of the support you currently have. If it is too cold to pour, then I would simply put the jack on some 4x4 or 4x6. If you are sure you will fix it in the spring, it doesn't matter what kind of lumber you use. If you may forget it, or it becomes a 'git'er later', then use pressure treat or ground contact lumber.

  • The main moisture problem is likely solved by trench in front of house. Stops runoff from steep driveway rolling into basement
    – House DiY
    Jan 21, 2020 at 7:14

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