Dig Out a Basement?

Homer Faucett

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36
I don't expect too many people will respond to this, but has anyone here ever dug out a basement under an existing home? My grandfather did this with his house, and a friend of mine dug out his own basement. I must have insanity running through my veins, as I'm considering doing this for my house as well.

Does anyone have any suggestions on how to make it easier? Both my grandfather's house and my friend's house were done by hand with 2-3 strong backs over a several week period. I'm hoping to get a good start, cut a large enough doorway in the foundation, and bring in one of those miniature bobcat deals that you walk behind to do the heavy lifting.

Does anyone have any books that would help? I've read a few accounts, and some good information is in the Taunton book "Renovating Old Houses" (EXCELLENT book if you have an old, old house).
 

Frank Pellow

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Toronto, Ontario, CANADA
That's going to be quite a job Homer, but I'm afraid that I can't help you with advice. When I was a kid, my Dad had a basement put under our hardware store but I remember few details. I can tell you that it involved jacks, LARGE timbers, and a lot of hand digging. Some horses were involved as well, but I don't remember how they were used.

Good luck! And please report about the project here.
 

Homer Faucett

Member
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36
If I do decide to go through with it, it won't be for about another year. I'm one of those that likes to overthink things before I start.

But don't worry, I'll take enough pictures of me digging dirt and being in way over my head. That's just how I like it.:)
 

Bart Leetch

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Clinton, Washington on Whidbey Island
It's really not all that difficult.

You could hold back from the original foundation on 3 sides about 3'-4' & install 4x12 Beams we spanned I believe 22' long by 16' deep with 4 or 5 4x12 Beams & steel posts.

We started by getting one inside of the end foundation that was going to be knocked out this supported the house while we removed that portion ot the foundation. This opened up the whole end of the under side of the house. Then we dug back in a ways from the short posts & replaced them with full length dirt floor to ceiling posts. Then we dug back a ways & installed another 4x12 & posts & repeated until we were as far back under the house as we wanted to be. Almost all the digging was done by a tracked end loader. We had already dug out for a big living room that was to be added to the end of the house. So we had plenty of room to maneuver the end loader. We even used the end loader to hold the beam against the bottom of the existing stringers. as we set the jacks in place to raise it to its final position & install the posts.

The beams we installed ran across the opening & the pre-existing stringers ran the other way.

By holding back from the original foundation on 3 sides it makes it simpler than having to raise the whole house. The house stays in place & you pour concrete wall about 3'-4' high & stud up to the bottom of the existing house. You could also pour a footer & lay up block if your a glutton for punishment.
 

Jeff Horton

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The Heart of Dixie
As a Home Inspector red flags go up when I hear this. Yes it has been done many times with no problems. Just be very careful digging around foundations. You don't want to do anything that would jeopardize the integrity of the foundation.
 

John Pollman

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Rochester Hills, MI
I'm pretty much with Jeff on this one.

Yes, it's been done many times successfully. But I really feel that if you really need a basement you should buy a house that has one.

Good luck if you decide to persue it!

John
 

Art Mulder

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3,383
Location
London, Ontario
Does anyone have any suggestions on how to make it easier? Both my grandfather's house and my friend's house were done by hand with 2-3 strong backs over a several week period. I'm hoping to get a good start, cut a large enough doorway in the foundation, and bring in one of those miniature bobcat deals that you walk behind to do the heavy lifting.

The way to make it easier is to hire it out. Safer too. And probably better for insurance. I wouldn't touch this myself.

Friends of ours did this. It is a nice basement now, but oooohhh what a mess.

Disconnect the electrical, gas, plumbing. knock a hole in the foundation, run through a pair of steel I-beams, bash them through the other end, jack up the house, knock out the old foundation, drive the bobcat down and dig it out, pour footings, pour walls, drop the house back down, pull the beams, patch the holes from the beams (or make them windows, I forget), reconnect plumbing, reconnect electrical....

Oh and then you have to patch all the mess on the main floor. Do you have an old house? They did, and over the years the heavy plaster walls had caused the floor to sag. Raising the house on the jacks levelled it within about 5 minutes, which caused HUGE sections of plaster to crack and come down. They need to completely re-drywall two bedrooms, and patch lots of other space. They also had to redo the fireplace, and so on.

You need to really really love the location, and some aspects of the house, to want to do this, IMHO.
 

Steve Ash

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2,437
Location
Michigan
I haven't done it, but I do know of several that have, and although I agree with both Jeff and John about safety issues, what I have seen done is a professional house moving company come to your home and lift the house. They have a steel structure they use to lift and support the house, it's built heavy for this purpose only. After it is supported WELL, then your excavating, foundation and wall crew come in to do their work, then the house is slowly rested on it's new foundation.

It's a lot of work, not cheap, but I have seen it done.


I like Johns answer...buy another house...only if you don't have strong sentimental ties to it. I couldn't get my wife to leave this house for one twice as nice, she is way to attached to it now.
 

tod evans

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ozarks
years back i was involved in a commercial job where we put a full basement under a 3 story, flemish-bond masonry structure...sitting on top of ozark limestone......if you`re serious about doing this project i`ll one finger out some of the relevent details? tod
 

Homer Faucett

Member
Messages
36
I'm certainly serious about this. Whether it ends up being a full basement or just a tornado shelter, I do at least need to dig out part of the earth under the house, because (1) it is just bare dirt within 18" of the main beams (much less in most places) under the house, and (2) I need to install some jacks under those main beams to take some of the bow and flex out of the floor.

The tree stumps are still sitting in the crawl space from where they put the house over the trees that existed when the house was built. Most have now rotted to where pieces can be pulled out, but that's a little wild. This should not be nearly as difficult as digging a basement in the Ozarks (my wife is from Springfield, MO--nothing but rock in her old backyard), as the dirt here is good farmland with pretty heavy clay below. There may be some big boulders when I get to digging, but I guess we'll find that out.
 

Frank Fusco

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Mountain Home, Arkansas
I have heard of it being done and sold a house (I was in real estate) that had it done. It required a conveyor to remove dirt and a WHOLE LOT of hand digging. Not a job I would even want to contemplate.
 

Jeff Horton

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The Heart of Dixie
(2) I need to install some jacks under those main beams to take some of the bow and flex out of the floor.

One thing to think about and it was mentioned previously. When installing jacks and leveling floors on an old house be warned that you can create a new set of problems. Recently inspected a house that apparently had a lot of settlement issues (before I got there) and they have leveled the floors. Actaully the house wasn't sitting on the foundation in many places so this job was rather extreme.

Consider the house had many years to settle. It didn't happen in a couple of days like the leveling did. Inside the house there were now baseboards that were inch above the floors. Much of the drywall had cracked due to the movement. Doors that no longer would close. Nothing major that I found (other than the house not resting a proper foundation but that is not important to this conversation). But it was still going to take a lot of work to correct the problems it caused. So just keep that in mind and don't raise the floors to much! It can cause a lot more problems down the road.

And good luck with what ever you decide.

Jeff
 

tod evans

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ozarks
homer, given the age of this structure......does it have a sound/conventional foundation?....i`ve seen homes built on dry stacked rocks and felled trees:eek:
 

Homer Faucett

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36
Thanks, Jeff. I certainly did not intend to try to level it all at once. The book I mentioned earlier, Renovating Old Houses by Nash, indicates that about 1/4" to ½" increments every 4 months or so (not quoting here, just what I remember from reading this last year) usually allows everything to properly conform back. The slope of the floors really doesn't bother me much, but the flex is a bit annoying. We did a temporary fix by placing some supports in specific locations that stopped the flex, but it is only a temporary fix.

Tod, excellent question with regard to the foundation. Yes, the foundation has been upgraded, which looks to have been done in the late 40's, early 50's. The Nash book has some good guidance on foundations and different types that are in the old houses, as well as what to look out for with regard to inappropriate fixes. Everything looks very sound, and the foundation is level, so I don't have much concern there.

What does concern me is that the main beam under the house does sit on top of some stacked rocks for support of the span. This obviously was not sufficient, leading to the rolling floors that we now have (probably due to the rocks sinking into the ground over time). It is only a 1200 square foot house, including an addition that has a separate foundation, installed in the 50's or early 60's, so shoring this up will not require substantial numbers of jacks under the main beam.

The house was built by my wife's great great grandfather in the 1850's, and you can see some of the framing in this thread http://familywoodworking.org/public_html/forums/showthread.php?t=1040 . So, there is some sentimentality with the house, and I have to admit that, while I scratch my head sometimes with the methods used, the load-carrying timbers in these houses are staunch and constructed with great craftsmanship (note the pinned 45 degree mortise and tenon joints that are at each corner beam in each room). All oak and poplar construction, it will probably outlast most of the standard homes built today. The location is ideal, and we'll probably live here for quite some time. Further, I don't watch much TV, and need some way to work out the stress of everyday life, so I do major home projects.

I have a tendency to research to the nines before I do anything, and was looking for exactly the types of responses I have seen so far. Thanks for the info thus far, and please keep it coming.
 

Frank Pellow

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Toronto, Ontario, CANADA
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Homer Faucett

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36
homer, given the age of this structure......does it have a sound/conventional foundation?....i`ve seen homes built on dry stacked rocks and felled trees:eek:


Todd, to get to your question a bit more, I have had more of a chance to "inspect" the foundation than I would like. We recently had to dig up the water line at the point where it enters at the base of the foundation. The poured footers look great, and they are plenty deep, so I'm not sitting on a ticking time bomb here.

If it was just a stacked rock foundation, I probably would have already started plans for new construction somewhere else on the property.
 
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