Does anyone have any referrals for digging into a basement to make the ceiling height acceptable? Any advice or connections in converting a basement into livable space would be greatly appreciated. Thanks!

Its called "underpinning"  they will break out your old basement slab and then lower the footing and foundation in sections, then install new slab at lower height giving you more headroom.  It is a large under taking and I can only assume the cost will have you think twice about doing it. 

I don't have any personal experience with it as I have only heard of it being done once in my 20 years of Remodeling buisness

@Zak Marinko I have done that personally. We dug a basement down about 2’ in Denver and then finished it. Erik is correct, it is a lot of work. After that is done you of course still have the basement finish to do. I am sure Chicago has a lot of company’s that would do it. I would ask a few different companies to give you a bid. It is free to get a bid and you will learn a lot. May be cheaper to pop the top.

@Zak Marinko I have a GC that can do this kind of work, but I agree that it will probably be cost prohibitive unless you have a 40k budget for that part of the project and then you plan to do substantial work on top of that. You would need to be in an amazing neighborhood in my opinion to make it work. 

Hi Zak

Hey Zak- How much ceiling height do you need to gain? We have done 1 dig down thus far and are doing a 2nd shortly. Both SFH on the NW side. Neither require underpinning and we are gaining about 8" of ceiling height or so. We dug down the max allowed before this was required. So our ceilings will be around 7'6, which is a nice height in our market. It's about half the cost of having to underpin. 

Originally posted by @Zak Marinko :

Does anyone have any referrals for digging into a basement to make the ceiling height acceptable? Any advice or connections in converting a basement into livable space would be greatly appreciated. Thanks! 

We looked at that on multi we own & it was definitely not viable & we already had two full 7ft basements originally dug by hand in the '60's. They already had 3 sets of egress doors, stairs etc but it was just not worth the effort.

So we added a new apartment as an addition to the building & we had it completed & rented within 2 months. We even FaceTimed the covid-isolated bldg inspector to expedite completion.

@Zak Marinko - Digging out a basement is no small job and you don't really know what you are going to get unless you do some potholing to figure out exactly how deep your existing foundation is.   Sometimes you can get lucky and just have to dig out and pour a slab, but oftentimes like @Erik B. brought up, you end up having to underpin.  

I love the idea of utilizing all the space you have, however, as @John Warren mentioned you need to be in the right neighborhood and have the right property for you to get the ROI you are looking

To further clarify, like others have said sometimes if you only need a few inches to pass code for headroom (ceiling height)  sometimes you can obtain this if your existing footers are far enough below the slab to accommodate the needed CH.

in the diagram you can see that there is some room to lower the slab before interfering w the footing. 

in my area when someone considers this it's usually to gain a foot or more of room which leads to the underpinning option and costs.

@Zak Marinko If the basement isn't currently living space, dig a few holes around the perimeter to see how low your footings are.  You will need to go about from the wall to about 18" away from the exterior walls.  What you should find eventually find is stone, field stone or concrete parallel to the floor.  You'll need a couple locations to determine if that really is the depth of your footing - it might not be even around the perimeter.  You can likely dig safely down to the footing and make it your new finished concrete floor level.  This is different than underpinning.  You can use that level to determine how much additional height you can get without the huge cost of underpinning.  Depending on your area or how deep you go, the holes may fill with water during a rain.  This will give you insight into how you'll need to size your sump pit and pump too.  The digging would be the first step an architect and structural engineer would have you do anyway.  Similar to the image that @Erik B. included, you will need a flooring spec for your permits. 

The digging out/hauling/new concrete is pricey too but a fraction of underpinning.  Happy to answer any other questions and share our recommendations & insights on a project we did recently where the payback was worth it to us.  

@Erik B. thanks a ton for your insight, I was not familiar with underpinning or that process. Sadly i won’t know for certain if I can avoid underpinning until I get to digging, but I’m looking to gain one foot for ceiling clearance, so hopefully the footing is deep enough! I’ll reach out if I have other questions

@David Meier that’s good to hear that you accomplished a 2 foot dig down. I agree that getting quotes is the best option, going to focus on that now

@John Warren I appreciate your insight and giving a rough estimate. I’ll send you a private message as well

@Jennie Berger that’s awesome to hear that you have successfully completed a dog down, and are working on a second. I’m looking to gain about a foot, seems like it’s on the edge of needing underpinning or not. I’m going to send you a private message as well.

@Jonathan Klemm Agreed, it seems like I will not know the extent of the project until some digging is done to find the footing depth. I’m going to send you a private message as well.

@Jerry N. that is a great idea to do some preliminary digging before getting started. I think I would chose to drop the floor as close to the footings as I can, even if it’s not as far as I want to go, to avoid underpinning cost and headache. I’m going to send you a private message as well

@Zak Marinko - if it's just the slab budget $30k for the dig and if you need to underpin it is about $50k - that doesn't include the water service, or any of the finish work

I agree with brie schmidt! Good luck with your project!

@Zak Marinko it looks like you have received some pretty detailed and insightful info on this already, which is great to see. In my experience as an Architect in Chicago; most Chicago residential buildings will allow you 2-12" before needing to underpin. That variation can obviously cause quite a significant impact, which is why it is a great recommendation to dig in a couple locations to see if you can find the top/bottom of the footing, or the bottom of the wall (I have seen cases with brick foundations and no footings). Another recommendation I have is to check at least 1 location along each of the 4 basement walls. I had one client where 3/4 walls had footings where we would have been able to dig down 4" to the top of the footing, or about 10" if we passed the top of the footing, but not the bottom(in order to avoid underpinning) however, the bottom of the rear wall of the house stopped only 1" below the existing slab... The more areas you check, the more informed you will be and the better information you will have to move forward with.

Additionally, another concern would be the depth of the existing sanitary sewer line(assuming it is below the slab) as sometimes these are 4-6" down, but other times they are only 1" below the slab. If you are planning to dig down 12" it will be likely that there will be some significant plumbing relocation work that will be needed to accommodate. You will also need to replace any existing intermittent columns and footings to work with the lower slab location.

In terms of building out the space for residential use, design concerns you could run into may include: providing (2) means of egress (depending on size of basement & type of building), Providing adequate natural light & vent (windows) for living/bedroom spaces, and access(stairs) to the new space.

@Samuel Pavlovcik - Really good point on an existing sewer line.

We recently did this for a project in Avondale, dug down about 2ft and it was almost 800sq/ft.  There is a TON to consider, as others are saying - you need to do some initial holes to see how far the current foundation goes.  It's expensive but if you do it right - it could be the right decision.   I have quotes I received, my cost, etc. if you're interested - PM me.