PWF Wood Foundation Wall Repair Questions

[gc717]

I'm considering whether to straighten one section (about 12' long) of a PWF basement foundation wall on one face of a 2 storey wood frame residence. The existing wood foundation wall is bowed inwards about 1" at the centre. There are no apparent leakage/moisture problems. The wall is about 20 years old, and while there's no indication of continuing movement, it represents a risk (and large adverse effect on resale value down the road). While one alternative is to do nothing, except for periodic measurement/monitoring, I prefer to flesh out the alternative of repair/remediation, before making a decision.

Likely reasons for the movement include exterior backfill too high, wrong backfill material, underdesigned PWF wall or some combination. Only time will tell after removing interior drywall to inspect the interior face of the wall; and exterior excavation to footing to inspect the exterior face (at least for one small section). As the basement is walkout at one end, I could excavate a small section by hand (with shoring) in order to enable a reasonable inspection down to the footing..

At that point, I'd get a structural engineer to inspect and advise on the probable root causes and remediation. My expectation is that after exterior excavation/trenching, remediation work would involve (among other things TBD) temporary support of the house load along the interior of that basement wall (full height basement), straightening of the wall, and refinishing on the interior (& perhaps exterior surface) of the PWF foundation wall.

Given the house load and exterior lateral load relieved, I'm wondering what the mechanics are for actually straightening the wall. My assumption (best guess) is that the process would involve use of some form of jack bolted to the basement concrete slab floor at the lower end; which is then angled upwards to the interior face of the PWF wood foundation wall; and then bolted/attached to a plate against the interior face of the PWF foundation wall. At that point I'm guessing that one would gradually and slowly extend the jack to straighten the wall.

If anyone has any background material on this process, or past experience to share on repair/remediation of a PWF foundation wall, your input would be much appreciated. Thanks.

[Wgoodrich]

I am picking up that you have a pressure treated wood foundation basement.

If the above is correct is also suspect you have a clay content in your subsurface soil that has swelled over the years during heavy rains causing exess pressure long enough to train your treated studs to bow permenantly. If I am correct and considering your statement these walls are 20 years old it leads me to believe you will have little to no more movement. What has happened in the past was when the basement was dug you had unbalanced fill that back filled along those walls. Then over the years as the dirt resettled to solid ground again it had increased the pressure causing your walls to warp by giving to that earth pressure while settling back in. Once it is done it should be stable from that point on especially after 20 years.

If it were me I would not redig around the basement and redisturb thus again create the increase of pressure causing more warpage and possible wall failure. What I would do is leave the wall as is only strip the wall covering inside the basement. Then I sould install by bolts and nuts about every other stud on those wall a steel plate 3/16th thick wide as the studs leaving these studs to remain open. This type construction not only had treated lumber but plastic water barrier and tar on the outside of that wall to make the walls water resistant.

Then I suspect you have a poured concrete basement floor. If this is true then I would leave a 1" air space from the old wall left as is and build a new stud wall from that concrete floor in the basement to the floor joists that is your basement ceiling area. This new wall should support the house unchanged if the outside wall gives out and starts to allow the house to settle. The second wall in front of the existing basement wall would be the same as the wall from your first floor supporting your second floor and roof.

Then you may insulate that wall but only with such material as friction style fiberglass insulation without paper as backing being a vapor barrier. You want this second wall to breath moisture not trap it between the two walls. Then you can drywall normally and finish the wall.

The above is my best advice.

You have an option of leaving that wall as is and installing properly sized girders under the first floor using treated posts at designed spacing allowing these girders and posts to support the house from the basement floor instead of the outside wall. Same method as above but no option to hide the bowed wall this wall. Cheaper and as strong but not as good looking.

The same technique has been used in my area where years past they used cement blocks that were not filled and were too small that created horizontal cracks at the frost line from outside when the ground froze it broke these cement walls making the walls angle inward about a foot below the first floor floor joists. This wall also supported the house so they needed to be shored up by using the above two options. This repair has been existing in many homes in my area for decades now with no further pushing in of the walls and the second walls not supporting along with the cement block walls as a duel support supporting the house above.

Many will give you a fear tactic big sale wild design like drilling anchors through your basement walls auger style then using much steel angle iron and huge bolts to pull these walls back straight. Sometimes this works but then you still will need to build a second wall inside to hide all the steel and huge bolts. Think about what is holding up your second floor and roof being the 2x4 outside walls you built on the first floor. The first paragraph is doing the same as you did above ground and it is called a wood foundation cripple wall.

Hope this gives you some ideas

Wg

[skysynergy]

Folks,

I also have a PWF home (Circa 1985) surrounded by clay with a 1-1.5" bow in my walls. Would a good alternative to 3/16" steel plate be to add a sister 2x6 stud nailed in a criss-cross fashion on every other existing stud?

I recently had a water main break in front of my home and it was subsequently flooded due to the 100-150 thousand gallons (literally) of water hitting front of my home. So, I thought I might shore up my walls while they were sans drywall ;0)

Thanks,
Rich