I'm currently digging a trench for some plumbing work in the basement of my 1919 craftsman home, and I have a suspicion that it doesn't have a footing. I need to dig down about 15 inches to get the right slope to connect with the main line, but doing that right against the wall feels a bit risky. It seems like a lot of weight is precariously sitting on this narrow strip of soil. Is it common for houses from this era to just be built directly on soil with a block foundation? Also, is it safe to dig right up next to it? Here are some pictures for reference: https://imgur.com/a/apIxpKD
2 Answers
It's definitely possible to build a block foundation without a footing, especially for slab floors, but it’s not the best practice. I wouldn’t recommend digging right under or beside the block wall. The main issue isn't just the vertical weight but also the weight of the soil pushing against the wall from the other side. It's better to be cautious when digging.
Yeah, I found out similar things while working on my 1924 house with a poured concrete foundation. When it comes to digging, the rule of thumb is to avoid digging within a 45-degree angle down from the foundation when you're parallel to the wall. That way you can keep the structural integrity intact without risking a collapse.
That’s good to know! The previous owners cut out about 18 inches for a DIY French drain, which wasn’t effective, and they poured a slab back over it but left a gap of 1/4 inch between the slab and the block. At least the wall hasn’t shifted since I’ve lived here!