I'm thinking about buying a two-unit brick building in Chicago that has an unfinished basement. My goal is to transform that basement into a third unit, but I've come across a ton of conflicting information online. Some sources suggest digging down, while others say it might not be necessary. Additionally, the cost estimates I've found are all over the place—ranging from $25,000 to $150,000. Has anyone here done something similar or have insights they can share?
3 Answers
The success of your basement dig really depends on your access. If you have the space to cut a hole in the foundation and build a ramp for easy dump truck access, it shouldn't be too rough. But if you're hand-digging in an urban area and wheeling dirt into a truck, that's going to be a nightmare. Expect the dig to cost over $100k before even factoring in permits. And remember, this just gets you the basic structure—you'll need to budget for the finishing work too!
I'm currently working on a similar project in Massachusetts. We have good driveway access and use 5-gallon buckets to remove dirt out the basement window. We're breaking up slabs and need to go 8 inches below grade for the foundation and new slab. It’s a long process, and while I’ll gain about 7 feet in height, going deeper has nearly doubled the costs due to underpinning and structural changes. Just the digout, waterproofing, and slab is costing us around $45 per square foot!
From my experience, digging down means you'll often need to repour a deeper foundation, which has to be done in small sections. It adds up quickly when you remove all that soil. Honestly, if you can find a property that doesn't require such heavy modifications, it might save you a ton in costs.
Yeah, you’re right about the access. I have a spot at the back that can fit a small trailer, but that cost range you're seeing online is really puzzling. Why is it so varied?