# Turning crawlspace into basement



## grouly925

I may get some wierd responses to this, but my wife and I are seriously considering it. The yahoo that built our house decided that he didn't need a basement, but proceeded to put in a 7 block crawlspace. We are well above the water table in our area and I proposed the idea to the wife to dig out our basement. We are unable to jack the house up because of an attached breezeway and garage, so I thought this would be a better option. Anyone have any experience doing something like this and any problems that we may encounter? I am 6' tall and i can pretty much walk down there just bending a little. I figure if we were to dig down another couple feet and pour a floor and some retention walls for the foundation, that we would then have a nice basement to store stuff in and get all the clutter out of our garage. Another nice thing would be to get the water heater and furnace out of the first floor laundry.


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## Michihunter

Only problem I could foresee is foundation and house support issues. I'd recommend an engineer to see if it is possible.


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## grouly925

I got a couple buddies that are contractors, I'll have them take a look. When I mentioned it to them before, none of them laughed in my face, so it must be at least somewhat of an option.


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## bigcountrysg

It can be done yes. But you should have someone look at it before you start digging.


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## ESOX

My house (so old the city has no record of it's origonal construction date) Was origonally built on a crawl. In 1954, when there was a 480 sq' addition added they jacked the whole house up, dug it out, installed a cinderblock foundation wall, then poured 5" of concrete next to that as a brick ledge, and poured a basement floor. They added steel beams and columns down the middle to support the first floor. I hate to think what that would cost today.


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## Joeker51

ESOX said:


> My house (so old the city has no record of it's origonal construction date) Was origonally built on a crawl. In 1954, when there was a 480 sq' addition added they jacked the whole house up, dug it out, installed a cinderblock foundation wall, then poured 5" of concrete next to that as a brick ledge, and poured a basement floor. They added steel beams and columns down the middle to support the first floor. I hate to think what that would cost today.


Neighbor behind me did something similar to what ESOX has mentioned about 10 yrs ago.
Took a baby Cat 1 one day running in and out to dig it out. Basement has 10 ft ceilings now. Have someone check it out. If you do it make sure that you have adequate drainage around the house. My youngest son now owns the house and the sump runs quite regular.


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## Scott K

However deep you _think_ you should go with it, add 2 foot to that.


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## grouly925

I agree about going deeper. My dad has 9' ceilings in his basement and it sure is nice. I am going to go down there and do some spot digging to see what is down a few feet before I look into it a lot further. See if I hit water at all, which I dont think I will. The sump that is in the crawlspace right now is at the low end, which is about 5' tall and it only runs during the spring run-off. The sump is about 4 feet deep, so I might run into some problems, but I'm not sure.

I can't jack the house up, which was the recommendation of one of my contractor buddies (without looking at my house). The breezeway that connects our house and garage would need major renovation to do that and I don't want to go down that road.


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## swampbuck

I have done some of that kind of stuff. IMO short of jacking the house up and adding 3 more rows of block, which is the best answer, regardless of the breezeway.

The other option would be to put steel beams under it, lift it enough to take the pressure off the existing foundation. dig a ramp down and use a small skid steer to remove the existing foundation and excess dirt. then pour a new footing/floor lay new walls back to the original height and set the building down, I was involved in just such a project under a hotel on mackinac island. It can be done, but wont be cheap.

Another easier option would be to do a smaller basement a few feet inside the existing footprint. I would go about 5 feet inside the existing dig a trench about 8 1/2 or more feet deep (depending on desired floor) measured from the existing floor joists put 6" of peastone in the trench and construct a wolmanized basement. after the framing is built run wolm. plywood around the bottom 4' with plastic on the outside of the plywood (working in the area between the footing and wolm. basement wall), then shovel the excess dirt from the floor into the area between the existing footing and the wolm. basement wall, finish the plywood and plastic (moisture barrier) up to the floor joists. for a floor you could either pour concrete or even better suspend a wood floor from the wolmanized basement walls if you make them tall enough.

This is actually a lot easier than it sounds, do a search on wolmanized basement construction. You would not alter the existing footing and would not be hauling dirt out, only wood in.


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## grouly925

swampbuck said:


> Another easier option would be to do a smaller basement a few feet inside the existing footprint. I would go about 5 feet inside the existing dig a trench about 8 1/2 or more feet deep (depending on desired floor) measured from the existing floor joists put 6" of peastone in the trench and construct a wolmanized basement. after the framing is built run wolm. plywood around the bottom 4' with plastic on the outside of the plywood (working in the area between the footing and wolm. basement wall), then shovel the excess dirt from the floor into the area between the existing footing and the wolm. basement wall, finish the plywood and plastic (moisture barrier) up to the floor joists. for a floor you could either pour concrete or even better suspend a wood floor from the wolmanized basement walls if you make them tall enough.
> 
> This is actually a lot easier than it sounds, do a search on wolmanized basement construction. You would not alter the existing footing and would not be hauling dirt out, only wood in.


This is what I was talking about doing. Basically, going about 4-5' away from the existing foundation and digging a trench to pour a retention wall for the current foundation. Then after this retention wall was complete dig out inside of the wall to the desired basement depth. That way I would have a "shelf" the whole way around the basement that I could box out into cabinets and storage, but still have a basement. I think it will be more grunt work than anything expensive. It may take time, but I have a lot of that. 

If you saw how the breezeway was set up, you would realize how improbable jacking the house up would be. Right now the door casing for the entrance to the house is flush with the breezeway ceiling, and the peak of the breezeway is flush with the top of the garage. It would require a lot of work.


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## paulywood

I have helped with this sort of project twice. My friend dug out more of the basement in his parent's house after high school. The ground was solid clay. He had to use a jackhammer to break it apart. There was no shoveling that. The second was at my grandpa's cabin. This was in pure sand and was fairly simple. It is more or less an aisle through the middle of the cabin. The water heater is down there. And it is set up so we can drain the water easily in the winter. There are posts set in concrete along one side of the aisle under a support beam. The other side was left with about 3 ft. of sand between the foundation and the aisle. The aisle walls are blocked of with plywood to hold the dirt back. Used a conveyor system from an old farm's feeding setup to haul out the sand. My house is over 100 yrs. old. At some point they dug out the old Michigan basement and put in a full basement. The kick walls are in 3-4 ft. from the foundation all the way around the house. That is the ledge you are talking about. Just make sure that the center of the house is supported. Mine still has the old tree trunk beams, complete with bark. I have reinforced them as the floor has started to sag. If you go into most of the old houses with basements you will see these kick walls and support beams running underneath with no problem.


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## grouly925

That is what I am talking about. Use an electric conveyor and a lot of grunt work, but eventually arrive at a decent basement. I plan to go down in the crawlspace this weekend and do some exploratory digging to see if I can hit water, and if I do, at what depth. I figured I would knock out some blocks in an area to have a spot to install an egress window and put the conveyor in that area. I am pretty interested in at least trying to get something done. I am going to have my buddies dad come over and estimate the cement costs, I can see that as being the ultimate cost.


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