Is a basement out of the question?

sapphire6917March 15, 2014

Hi All!

I believe I will finally be in a position this summer to start working on my very neglected carriage house. It needs a ton of work, not the least of which is a foundation. It appears to have been built on wooden beams and parts of the building are sitting directly on dirt which has caused the structure to lean backwards. Since there is some digging that will be required to fix the building, I'm thinking it's the perfect opportunity to dig out a basement. The building will be used for recreational entertainment so the basement would be added space for that as well as space for the utilities to live. Does anyone have any thoughts on why it wouldn't work? I live in the downtown area of my city so one friend asked where I would put the dirt that was dug up. No idea. When people build houses, they must put the dirt somewhere so I would guess my dirt would go to the same place!

I guess here is a good place to mention that, while I can easily work a power tool, I am not the least bit handy or carpentry inclined so this is my attempt to educate myself a bit before I start talking to contractors!

Thanks for your help!

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Usually the company that digs the basement hauls away the fill dirt.

Other construction sites are often looking for "clean fill dirt".

Have you checked city zoning and building codes to make sure you have all the plans and permits checked? Digging holes requires shoring and such that they want to know you have.

    Bookmark   March 15, 2014 at 11:58AM
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Thanks for the response, Lazygardens! It's good to know that I don't have to worry about the dirt!

No permits have been pulled because nothing has been done yet, including finalizing the plans and selecting a contractor. I am in the very early stages of this renovation and just trying to get a clear understanding of what's possible. As soon as I get with the architect and figure out exactly what will happen, all of the proper permits will be pulled.

    Bookmark   March 15, 2014 at 12:56PM
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A house moving contractor will raise your carriage house up and level. It isn't usually that much more work or expense to excavate a full basement than it is a proper foundation. There are many variables, especially soil types and regional construction practices. I was in the first basement in Florida I've ever been in just last month.

    Bookmark   March 15, 2014 at 3:26PM
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Thanks, Trebruchet! I lived in Florida for a few years and never saw a basement!

I hadn't considered a house moving contractor! The carriage house is in really terrible shape. Of the handful of contractors that were even willing to go inside to evaluate it, they have said it is racked and pitched, which I presume is leaning and crooked. The roof is also severely compromised which has led to a lot of moisture damage over the years. Because of all of that, I have been told that it would need to be raised very slowly and very carefully, using cables. An alternative suggestion to lifting it is doing something with pier footings and support beams. I have no idea yet what the final solution will be but I've been discouraged to take on adding a basement. I'm not sure if it is because there's such an enormous amount of work to be done on the building that they were thinking it would be too much or if there are structural/safety reasons why I shouldn't so I figured I would ask. I know it's no five minute job to dig out a basement but I would think that it would be easiest to do in the process of creating some kind of foundation.

    Bookmark   March 15, 2014 at 5:23PM
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Given enough money, almost nothing is out of the question. Make no mistake, though, this would be a costly project. First there would be whatever shoring is needed to compensate for the water damage. Then there would be the jacking - a process that always entails at least some risk for old buildings. The carriage house would have to be raised considerably to allow for excavation beneath it and it would have to remain up on the cribbing until all foundation work is completed.This would cost quite a bit more than a one day jacking project. Then there's the excavation itself, foundation, cellar floor, etc.

If it were me, I would definitely get some estimates for disassmbling the carriage house and rebuilding it - using whatever original parts can be salvaged. You could then have the foundation built much more easily and quckly as well as avoid the expense of jacking. This certainly wouldn't be cheap either, but I think it would be considerably less than the first option.

    Bookmark   March 16, 2014 at 6:36AM
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Thanks, Akamainegrower! Great points!

That is similar to what I was told by an architect who politely refused to work on the restoration. The problem with that is as long as I am restoring the current structure, I'm grandfathered in as far as the codes for the size of the building. The minute it comes down, I have to follow the current code which doesn't allow for a two-story structure. One contractor thinks he can basically take down and rebuild one wall at a time but he hasn't actually been to see the building yet due to the weather.

As for the excavation, there are two large doors on the front that can be removed. I'm told that opening would be plenty sufficient for the "bobcat" to get in and dig out the basement so it wouldn't have to be done while the carriage house is in the air. I hope to catch up with a guy who actually does that work to confirm that soon.

    Bookmark   March 16, 2014 at 7:49AM
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Digging in a closed space like that - have you considered the Bobcat xost fumes?

    Bookmark   March 16, 2014 at 1:34PM
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Hi Mxyplx! I have not considered the fumes but that is one of the things I will discuss with the bobcat guy when I talk to him. Thanks for bringing it up!

    Bookmark   March 16, 2014 at 3:57PM
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If you're certain that no exceptions can be made to the code (even for historic buildings which will have the same footprint?) then the bobcat idea is probably the best you can do. I do have some difficulty imagining how this can be done to provide a cellar with much head room at all, but the bobcat operator would know best.

If you choose this option, it ought to be possible to construct the foundation one wall at a time. Excavate under one wall, create the foundation for that wall, excavate the next, and so on. Following this pattern, the structure could theoretically be repaired one wall at a time. This assumes at least one wall - the one to start with - is structurally sound enough to withstand the excavation beneath it.

This would also be time consuming and therefore very costly, so I'd definitely check for possible code exceptions in the most polite and persuasive manner possible.

Not sure if its available in your area, but there are systems which can drill holes for piers from the outside of the building. If you live in a not-to-cold climate, piers with walls and insulation between might work, but you would probably have a rather odd looking structure.

PS: Does the code also require you to use the exact same footprint? If you could shift everything by even a foot or two to one side or the other, everything would be a lot easier - excavation, foundation, wall by wall reconstruction.

    Bookmark   March 17, 2014 at 6:41AM
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Have you Googled >excavating a basement under an Existing houseSome do it with wheelbarrows or buckets and hand excavators. Crazy! Lotsa hits some with video. About half thot it was worth it. Half thot it wasn't, Half wouldn't do it again. Half would move the house over and back. Half would build a basement then move the house.
I wrote up a long list of problems - you don't want to read it. So I'll just give you the 1st one:

1. Don't count on a Bobcat driver to be knowlegable on fumes. Down in a hole like that the fumes build up on the bottom. You could be walking knee deep in fumes and not know it. Bend over to tie a shoe get knocked out fall down and drown.

Might google that too. I worked with a guy damn near drowned in a pool of gaseous nitrogen. You couldn't see it or smell it. We pulled him out just in time. There was a leak........

This post was edited by mxyplx on Mon, Mar 17, 14 at 12:03

    Bookmark   March 17, 2014 at 12:01PM
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@Akamainegrower, unfortunately, my house and carriage house do not have a historic designation so I'm not afforded many of the exceptions that a historic building would have. And I am in a crazy cold climate (currently 26 degrees) so the piers and insulation probably won't work but I will definitely explore every angle possible regarding shifting the structure.

@Mxyplx, I will probably spend the rest of my evening following Google links for excavating basements! My main house has a basement with decent headroom but it is completely unfinished and is not dug out under two of the rooms in the house. I have had more than one contractor tell me that they can bust up the cement floor to dig down and give me more headroom in addition to digging out the additional rooms. Now that I can't even imagine doing!! That sounds a lot like what I will find on those links. For the carriage house, especially with the doors off, there will be a TON more room to move around and dig. I'm sure it won't feel so open as they go deeper so I will relate your story to the bobcat guy and see what kind of feedback he has.

I have also attached a link to one of my previous posts where, if you scroll down a bit, you will see a picture of my beloved!

Thanks again for all of the feedback!

Here is a link that might be useful: Picture of carriage house

    Bookmark   March 17, 2014 at 5:03PM
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Great Jumping Jehoshaphat Pocahontas and John Smith!

I do believe I'd dig a big hole in front same deep as you want the basement and slanted toward the ah- the ah -house? Then dig out the basement front to back. Shore up the walls as you go. Hire a couple miners. That way you could carefully carve the dirt away. A bobcat would do that. I never drove one. Drove a 966.

That house has a lot of latent potential. All latent. :-) I see why you like it. Sure hope you achieve your goal.

    Bookmark   March 18, 2014 at 12:01AM
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That was a true Laugh Out Loud, Mxyplx!!! On the one hand, she's in better shape inside than she looks. On the other hand, that picture was taken a few years ago and she's lost more roof shingles so she's developed a few more wrinkles. That's why I don't want to leave her exposed for another winter.

There's no doubt in my mind she can be restored but it's the little extras, like a basement, that I'm not sure about. But you see what I mean about removing those doors and the first floor being almost completely open? I will check with bobcat guy about the possibility of digging it from the outside in. I love options!

I got home late but I did look a little into excavation under existing buildings, mostly in relation to the main house. Sshhh! My dream is to finish the basement in the main house and then dig a tunnel to connect the two basements!

    Bookmark   March 18, 2014 at 6:35AM
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A bit off topic and I had forgotten.

1959-60 at that time you could lease a gold mine in the Sierras from the govmnt for nothing (I think) if you put $100 worth of improvement into the mine. A friend did that and every year he'd buy $100 of lumber and we'd shore up the mine tunnel for a few feet. Quite an experience. There was an old cabin on that claim which was our main attraction.

One year an old man about 80 stopped by. He'd been in the Klondike gold rush in 1900 or whenever it was. He pointed at a pit nearby and said it was the original shaft - the 49ers didn't mess with tunnel shoring - just dug in, crawled in and went for it. He had a nugget in his wallet the size of my little finger.

    Bookmark   March 18, 2014 at 10:34AM
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How cool is that?! And what a brave man you are! I grew up a tomboy but, over the many years since then, I have grown an aversion to dirt. I don't even want to grow anything in my backyard! And I haven't been in tight underground tunnels like that since my old foxhole days and they are not fond memories. I've been teased that most of the money I spend on the construction of the tunnel will be in making it look like everything BUT a tunnel! It's just going to be a pass-through structure but, for sure, it will be the lightest and brightest and roomiest pass-through tunnel known to man!

    Bookmark   March 18, 2014 at 12:58PM
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Side bar from a native FL girl:

I lived in Florida for a few years and never saw a basement!

That's because in most of Florida, the water table is so high that if you dig a basement you get a swimming pool. ;-) The water table will even pop fiberglass pools out of the ground if you don't keep them full of water.

If you live in a coastal zone where they are raising the houses "Key West" style, the "basement" is the ground floor.

Not saying there aren't any basements in FL, but there aren't many!

Always ;-)

    Bookmark   April 16, 2014 at 11:54PM
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Hunzi, if i'd ever seen a pool popped out of the ground, I might think I had officially seen it all!

I had actually been told about the water table issue in relation to basements when I was there. It's unusual NOT to have a basement here so I was scratching my head when I first got to FL.

Boy, do I miss that heat! What I don't miss is the bugs!

    Bookmark   April 17, 2014 at 4:53AM
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