Foundation crumbling under a balloon-framed house – how to retrofit?
Hi All – I live on the Colorado Front Range in a home built in 1947. I bought the place in 1994 and spent about 5 years bringing everything aboveground up to code, including framing, wiring, plumbing, insulation, windows and doors. I’m dealing with a crumbling foundation, however, that is threatening to undermine all of my renovations. The foundation is concrete poured into an uneven trench dug about 10” deep into the soil. There is no steel reinforcement in the foundation. The foundation is steadily breaking apart bit by bit, with new cracks forming every spring after the frost heave season. I’m trying to figure out if there is a way to rebuild or otherwise stabilize the foundation under the existing home, or if I need to scrape it and start over. The home is 1500 square feet, single story, and balloon framed (https://www.oldhouseweb.com/how-to-advice/balloon-framing.shtml), with a main structure of 750 square feet with three additions. Under the main structure a concrete slab was poured between the foundation walls and floor joists were laid directly on the slab. I’ve helped renovated other foundations by jacking up the entire building home and replacing the foundation underneath, however I don’t see how I can do that considering how the home was constructed. But I am curious to hear if anybody on this thread has any suggestions for how we might pull that off? Or are there other methods to replace or stabilize a foundation in situ that you’d recommend I consider? Thank you for any thoughts you might have.
Replies
Anything is possible given enough time & money.
The best solution is a new and proper foundation for the site conditions that exist. From what you describe, it's probably a new foundation.
Thank you, I wondered if that might be the solution.
Devil is in the details, but if the floor joists are on a slab, and the roof rafters and joists are connected to the walls, it would seem possible to construct a temporary wall to hold up the roof and walls a bit inside the walls, supported by the slab, and then dig out and replace the foundation working from outside the suspended walls.
It is also possible to do this in sections.
There are firms that specialize in this type of work.
That is a very interesting idea that I hadn’t considered at all. I’ll have a look into this.
There are also products that may apply and provide other options.
https://www.wfphelicals.com/ and other folks may be able to help.
As unclemike says, the "Devil is in the details."
As a structural engineer involved in CT's foundation replacement issues, I know of many approaches that can work. BUT, given what you've described thus far, a careful forensic examination of the various phases of construction (the additions) is in order. Such investigation is likely to be rather invasive (i.e. removal of finishes) to assess the structure. As I stated previously, anything is possible given enough time & money.
I would not speculate on how this could be done without first examining how the original home and its additions were constructed.
Great points. I hired a structural engineer to examine the foundation, and he opined that the foundation would likely have to go at some point. We ran some of the cost numbers through a spreadsheet together, and I think the price point would approach the cost to scrape and rebuild.The interior floors and walls, door openings, and window openings are all in various states of skewness so that little in the home is square or level. It would be difficult to preserve that cattywampus condition in a rebuild. Stabilizing the walls and ceilings with a new foundation would likely require other significant interior repairs. Unclemike42 and ct_yankee, thank you for these thoughts. As you suggest, I’ll see if I can find a firm that really knows what the heck they are doing on problems like this, and see what they say.
Given ample time and financial resources, anything becomes achievable.
In light of the described circumstances, the optimal resolution would likely entail constructing a fresh and suitable foundation, considering the existing site conditions.
Regards:
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