Pergola sinking

[Phil Phelps]

Greeting folks,
I am re laying the flagstone in my back yard. The pergola you see has been here since '52. In '53, it was dressed with some gingerbread on each post and had two tool boxes built on opposite sides, all of redwood. The elements had taken their toll on the addition and I demo'd them today. Noticing that Algerian ants had built their mounds around the front two 6x6 redwood posts, I cleaned away about a cubic foot of dirt on either side. Then, within about fifteen minutes, the pergola dropped down about six inches. How do I set the posts? They are not in concrete and I don't know how deep they are set. I am setting a 4x4 block on either side of the soffit and using 2x4's and bottle jacks, I intend on raising it level. What happens if both those posts have rotted? If they are okay, i intend to dig a few inches past them and use a mix called Maxim. I am open for suggestions.
Thanks, Phil

[Terry Achey]

Phil:

FWIW - I think if this was my problem and I would most likley consider cutting off each post (one or maybe two at a time) at least two or three feet above grade and support the structure with temporary supports. Then, excavate deep and wide enough to pour a stable concrete foundation for each post using a sonatube. Cut and install a new section of post slightly larger in diameter then the existing post so you can make a nice transition with some trim. Take some doing but you really need to keep the posts out of the soil.

Looks like a very nice pavillion worthy of saving. Good luck.
Terry

[Terry Sparks]

Personally, I would cut the post at ground level, pour a concrete footing to groung level and set in a Simpson Post Tie to connect the posts with your footings.

[Joe Shinall]

I agree with Terry... Which one? Not sure of that yet, but I think I agree with one of em...

[Glen Butler]

Personally, I would cut the post at ground level, pour a concrete footing to groung level and set in a Simpson Post Tie to connect the posts with your footings.

This is what I what thinking. Temporarily shore the whole structure up. The simpson tie you are looking for is an EPB66. You will want to cut the posts about 1" above soil. You may also consider temporarily attaching each of the posts together by screwing a 2x2 to them. This will help keep them plumb and oriented properly. In Utah we are required to have footing 30" into the ground to get below frost level, but I doubt you get frost in TX and shouldn't have to worry about such things.

[Myk Rian]

Seems to me the ants have built deep into the ground, and it's sinking into the nests. You'll have to deal with that situation first, then work on fixing the posts.