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Old 01-26-2009, 11:35 PM   #1
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Basement floor advice


So I want to finish my 1000 sq ft. basement.... its never been finished and my house was built in 1903. It has masonry walls and very little/no water issues. My problem is that the the floor slope is pretty dramatic and not level. Secondly, building codes state that I need at minimum 7 ft ceilings. However, I have about 7'3" in the center of the basement (where the drain is) and about 6'6" near the walls.

At first I thought I would just keep the floors concrete and paint them, or maybe throw down some rugs, and ask for a variance on the ceiling height.

Now I'm thinking about cutting up the concrete slab, excavating 6" - 12", and putting in level floors with maybe grooves for drainage and installing a sump pump. I could also add a vapor barrier under the new floor and install a bathroom in the basement. Is this feasible? What kinds of problems could I get into? What unanticipated costs could I incur?

Thanks!

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Old 01-26-2009, 11:57 PM   #2
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Basement floor advice


sounds like alot of work. I'd ask for the variance.

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Old 01-27-2009, 06:39 AM   #3
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Basement floor advice


2 key phrases:1st, ' built in 1903 ' - you might find code doesn't apply to you as house was blt prior to code change; 2nd, ' very little/no water issues - be VERY sure about this as you're betting lots of labor, $$$, & aggravation wtr won't find your bsmt.

demo & replacement's big work as you probably know especially the part about addl excavation which involves structural wall issues,,, i'd be looking for a structural engineer.

' unanticipated costs ' ? ? ? one's mind/imagination can only soar
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Old 01-27-2009, 07:46 AM   #4
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Basement floor advice


My first thought about excavating 6-12" is that you may find yourself digging lower than the footing of your existing basement walls. That is something you can't do without a serious plan.
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Old 01-27-2009, 08:56 AM   #5
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This is from experience: lifting a house or lowering a slab or replacing a foundation wall is tricky. In most cases the work involves tools and equipment that you can't rent somewhere. I wouldn't shy away from it, but I do this for a living. You should do yourself a favor and call either an engineer or contractor with experience in this work, and get a feel for what's involved. The last thing you want to do is undermine the footing and have your foundation cave in.
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Old 01-27-2009, 10:42 AM   #6
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My first thought about excavating 6-12" is that you may find yourself digging lower than the footing of your existing basement walls. That is something you can't do without a serious plan.

The basement is open and supported by 2 brick columns near the center of the space that prop up I-beams that run the length of the house. There are two iron columns near the staircase near one end of the space, also against the I-beams.... I think these were added later.

I have to rip up some of the floor to get to the sewer line to install a bathroom anyway, so I thought it would be worth it to level the floors and give myself more headroom while I was at it. Do you think the brick columns are supported below ground, or they start at the slab? Would it be feasable to excavate around these supports, as to not worry about having the house cave in on my head?

Thanks again
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Old 01-27-2009, 11:12 AM   #7
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won't make a damn'd bit of difference what we think as none can see your house from our house,,, UNLESS you think you're well-qualified, call in a pe OR pro,,, if you are, why're you posting in here ? you'll probably need stamp'd drawings in order to pull the permit, anyway.


excavate around a supporting column ? ? ? not in my lifetime UNLESS i had the place well-cribb'd.
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Old 01-27-2009, 11:15 AM   #8
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won't make a damn'd bit of difference what we think as none can see your house from our house,,, UNLESS you think you're well-qualified, call in a pe OR pro,,, if you are, why're you posting in here ? you'll probably need stamp'd drawings in order to pull the permit, anyway.

Will post pics when I get home....
I will likely consult an Engineer who is already working with me on other projects... just wanted to get a sense before wasting more brainpower on this...
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Old 03-05-2009, 11:30 AM   #9
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You should really get structural drawings and a permit if you're going to be lowering your basement. There are so many things that can go wrong.. without a permit, even if you do it and don't weaken the structure, the City can order you to put everything back the way it was; undoing all the work.

Lowering a basement and underpinning the foundation and support columns is complicated and expensive. If you think you can save a few dollars by doing it yourself, but you don't know exactly how it works, and from your questions it doesn't sound like you really know totally what's involved, you can potentially cause a lot of trouble for yourself and even possibly destroy your house.

Don't hire some guys who say they are going to 'bench' it. That's not the right way to do it. And don't hire some clowns who say they can do it for $20,000 or so. Those guys are going to be cutting corners for sure.

Just a suggestion: if you're going to lower it, 6" isn't worth the effort. The actual distance down is not the major component of the cost. You can expect to pay several tens of thousands of dollars to lower your basement correctly in a way that won't damage your home. The difference between 6" and 1'6" or 2" isn't what's going to determine the affordability for you.
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Old 03-05-2009, 12:09 PM   #10
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You should really get structural drawings and a permit if you're going to be lowering your basement. There are so many things that can go wrong.. without a permit, even if you do it and don't weaken the structure, the City can order you to put everything back the way it was; undoing all the work.

Lowering a basement and underpinning the foundation and support columns is complicated and expensive. If you think you can save a few dollars by doing it yourself, but you don't know exactly how it works, and from your questions it doesn't sound like you really know totally what's involved, you can potentially cause a lot of trouble for yourself and even possibly destroy your house.

Don't hire some guys who say they are going to 'bench' it. That's not the right way to do it. And don't hire some clowns who say they can do it for $20,000 or so. Those guys are going to be cutting corners for sure.

Just a suggestion: if you're going to lower it, 6" isn't worth the effort. The actual distance down is not the major component of the cost. You can expect to pay several tens of thousands of dollars to lower your basement correctly in a way that won't damage your home. The difference between 6" and 1'6" or 2" isn't what's going to determine the affordability for you.

Thanks. It's been a while since I started thinking about this project. I have discussed it with a structural engineer who came out to see the basement. The slab is NOT original and was poorly laid out. It is NOT structural. The grade from the middle of the basement to the walls is more than 1in/ft and patchy. I will probably not lower the basement any but just level the floors (actually run a new slab at 1/8"/ft). All the footings should be at the same height so I won't get anywhere near the wall footings. I should gain about 8" near the walls doing this. I will do the excavation myself. The engineer stated that no bracings were necessary. I am working with a contractor and will get a permit for the work, since I will be adding a spiral staircase to enter the basement.

I will still post pics... I am excited to start this project. Thanks!
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Old 03-06-2009, 01:19 AM   #11
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keep us posted. especially me. i am toying with the idea of lowering the floor in part of my basement. i was thinking of just doing to it to about a fourth of it, and leaving like a foot or so from the wall so that i don't need to worry about foundation (i think). i am nowhere near starting this, so just idlly thinking about it. my house is from 1893.
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Old 03-06-2009, 10:20 AM   #12
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Originally Posted by 2031pratt View Post
keep us posted. especially me. i am toying with the idea of lowering the floor in part of my basement. i was thinking of just doing to it to about a fourth of it, and leaving like a foot or so from the wall so that i don't need to worry about foundation (i think). i am nowhere near starting this, so just idlly thinking about it. my house is from 1893.
As far as I understand it, you can go lower than your foundation footing, but you have to slope the floor at a 45 degree angle from the footing down (as far as you want ot go), and try not to have the house cave in on your head.
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Old 03-06-2009, 11:04 AM   #13
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In determining to lower your floor or lift your house, you have to take into consideration the sewer and storm drains. If you only have a couple of feet drop between you and the city, then you will have to factor that in as well. City might not be able to lower sewer. All of this is assuming ( I know never assume) you are on city sewer and storm. Just my 2 cents worth.

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Old 03-17-2009, 01:04 AM   #14
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Basement floor advice


There is another thread on this topic to which I just posted:

Dig out basement (lower floor)

- anyone here have something to add?

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