Replacing shallow basement/block foundation with deeper poured one? (OT for rec.ww)

[Max]

We have an old basement that is about 6'6"" at it's highest point, with a block foundation. The floor is poured concrete, not flat, with the usual(?) small stress cracks.

I was wondering about the feasibility of jacking up the house, removing the old foundation, digging a little deeper, and putting a new poured foundation with lots of (8'+) headroom.

I am specifically -not- interested in just digging out the floor. I'd lose too much floor space that way, and I really would like to get rid of the old block walls.

Anybody know anything about this?

I've done some googling, and all I've found seems to talk about turning crawls into full basements. Not quite what I'm about.

I know this will be expensive, but it might be the way to go for our situation. Having a new finished basement might be more cost-effective than moving, if it comes to that. We bought before the real estate price run-up of the last 5-6 years and couldn't afford to buy in our neighborhood today!

Thanks for your time,

Max

PS: I crossposted to rec.woodworking mainly in the hopes of getting more input, but also because this effort might result in my own indoor shop space instead of an unheated garage. ;-)

[Inspector Terry]

This is do-able... COSTLY yes, but do-able.

Contact house movers in your area for the best results.

Good Luck!

Terry

[Arvid Sorsdahl]

[tbasc]

You could consider leaving a ring of slab around the perimeter of the basement and digging deeper. You ought to consult an engineer, since the soil type has a lot to do with this working. Don't forget that railing the house includes disconnecting and reconnecting plumbing, gas and the like. T

[Doug Houseman]

In article , Max wrote:

I am going from memory, I was 12 when we did this back more that 40 years ago. We cheated and dug out, ourside the current walls and put footers in down two sides of the house, leaving the current walls in place (they were field stone - more than 100 years old). then we put block up and finally got the walls of the house (which were outside the current basement area) on the two block walls. Once that was done and the house was supported on the two long walls, we opened up one end of the house with a back hoe - so that we could get in under the house. Using a small cat (a 1940's vintage one) we then went under the house and dug out the basement (it was 5 feet deep to start) again leaving the old stone walls in place at first. Once we had the center deep enough that the cat could freely run thru the basement, we ran support beams from the new block walls thru holes in the old stone walls we chipped out (this part I remember because I got to hold the star drill). Once the beams were in place and the house was solidly on them, then the cat undercut the stone walls and tumbled them into the center of the basement (the operator was very very good). This done we removed the stone and the other junk from the basement (i wish there had been eBay then). Fresh sand and leveling the floor area, then poring the floor and end footers at one time. Finally block walls on both ends - the block layer was also very good and had planned the way the blocks would interlace on the corners so that we did not have to get around stub walls on each side.

Today the basement is 40 by 20 with 7' 8" under the beams. It had been less than 5 feet deep and less than 20 by 12.

It took some old timers who really knew what they were doing, but the house is still occupied by my parents.

Now putting in picture windows is a whole nother story! Charcoal and vertical log walls!

Cheers

Doug

[Jim Behning]

Last year I saw them doing this in Colorado. Well not really. They jacked up the house. Pulled it out of the way 50 feet. Dug out the old basement and installed new poured concrete walls. They slid back the old house and added on to the back of the old house.

[J.A. Michel]

It can be done. We had a house with a crawlspace, and looked seriously at putting a basement under it. It was a 26'x48' ranch style house. We got estimates, and a poured basement was going to cost $27,000. The housemovers needed $12,000 just to jack it up and down. In the end, we ended up building a new home complete with the basement we wanted.

If you go ahead with the project, get a basement with 9' walls. We did, and it's nice to have the extra headroom. You might also want to add perimeter drain tile and maybe even have the dirt treated for termites one the old basement is gone, but before the new one is poured.

There's lots of things to consider with a job like this. Choose your contractor carefully!

Good Luck!

[Greg]

The houses in my neighborhood have 1/2 basements and 1/2 crawlspaces, and a neighbor dug out his crawlspace. He carried out the dirt with buckets and extended his existing crawlspace wall downward with concrete blocks in small sections at a time. It took him 2 years after his retirement, he suffered 2 hernias from the digging and carrying, and his backyard is now 1 foot higher than before from all the extra dirt. But it probably cost him very little money.

[Jim]

This Old House had a project like that. They jacked the barn up and poured a new foundation under it.

Their budget though seems to be unlimited.

Jim