can one deepen a basement (don't LOL)

[oldielocks]

i am buying a little house with a full basement, but it only has 7-ft headspace. can anything be done. thanx

[jimbo]

I've seen it done. You need to have a general contractor or engineer look at it. The issues with digging the basement deeper is how does it affect the foundation/footers.

If money is not object, there is another technique....raise the house. Saw that done here once. House was on a crawl space....maybe 3 feet. They raised the house up, dug out some, and put a whole new "first floor" under the existing house. $$$$$

[krow]

The footings can be "under-pinned" with shrink free cement. In most cases, they will ask you to install rebar up inside the new extended footing and tieing in to the horizontal concrete floor. (Each state or province will have their own critiria) It is usually dug out and poured at 4' intervals. They usually recommend 4' on opposite walls at 1 time ie: 4' on west wall and 4' on east wall on the same day. Then continue in this fashion until the entire perimeter is done. (check with your local authorities for the bylaws that apply to you)

Other methods include digging in front of the footing in the basement and pouring in fron't of the footing . General rule of thumb is, for every 1' down, the cement must stick into the basement 1'. This method is less time consuming, but not the greatest looking. Too much lost floor space to have the 1 ' ledge around your entire basement.

[oldielocks]

I've seen it done. You need to have a general contractor or engineer look at it. The issues with digging the basement deeper is how does it affect the foundation/footers.

If money is not object, there is another technique....raise the house. Saw that done here once. House was on a crawl space....maybe 3 feet. They raised the house up, dug out some, and put a whole new "first floor" under the existing house. $$$$$

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thanx jimbo. money is an object as the whole house is only $79,000.
perhaps when i have an inspector come in to check the house, i'll ask him
also (if he would know).

oldielocks again!

[oldielocks]

The footings can be "under-pinned" with shrink free cement. In most cases, they will ask you to install rebar up inside the new extended footing and tieing in to the horizontal concrete floor. (Each state or province will have their own critiria) It is usually dug out and poured at 4' intervals. They usually recommend 4' on opposite walls at 1 time ie: 4' on west wall and 4' on east wall on the same day. Then continue in this fashion until the entire perimeter is done. (check with your local authorities for the bylaws that apply to you)

Other methods include digging in front of the footing in the basement and pouring in fron't of the footing . General rule of thumb is, for every 1' down, the cement must stick into the basement 1'. This method is less time consuming, but not the greatest looking. Too much lost floor space to have the 1 ' ledge around your entire basement.

**************************************
thanx, krow. this is a 90-year-old house and its still standing; must be built solid. your first idea is a good one and i will certainly check it out. perhaps
the inspector i hire will know.

oldielocks

[Cookie]

Being I am only 5 feet tall, 7 foot in a basement would be fine for me. You got to figure, too how often are you going to be in the basement? If there are other properties for sale, why not continue looking? And, put that money you would had spent in raising the house into another property maybe, of greater value?

[Nate R]

What's wrong w/ a 7 foot basement? You looking to finish it? @ 79K, I would think it's not worth going deeper if it's 7ft as it is.

FWIW, I have a bedroom w/ a 6'11" Ceiling in our 85 year old home, and our bathroom is 7 ft. :eek:

[Bob NH]

A 90 year old house probably has lath-and-plaster walls and ceilings. Anything you do that moves the foundation will probably crack the plaster.

I suspect that it will cost $20k to $30k to get an extra foot or so in the basement. Would you pay that much more for the house? Could you sell the house for at least $125k to pay for the higher ceiling and the trouble and risk you will go through to change it?

[Bill Arden]

7 feet feels claustrophobic. I wounder if mirrors could be used to make it look higher.

I know one couple that jacked up there house and used 5 gallon buckets to dig an entire basement.

The stepped floor system can be made to look ok if you add cabinates and other wall furnishings.

[frenchie]

If you're looking at 20-30k to dig down a foot... that's about what it costs to raise a house. Definitely look into both options; sometimes raising is cheaper than digging.

[shag_fu]

Dropping a floor was on of the first jobs I worked on. Started with a 6'6" height ended with tall 8' or 9'. It was a LOT of work. Either way you go jacking it up or digging down will have an affect on the wall esp lath and plaster. Its not an if, but how much will the rest of the house be affected by this undertaking. The 20-30k is just for the concrete work. That usually does not include fixing the rest of the aftermath.
With this kind of expense you have to look at the return on this "investment" if you will sell the house in this lifetime. The guy we dropped the basement for had no problem throwing cash around he just wanted a more usable basement. At the price you mentioned, unless the houses in that area sell for 150k and up, this prob is not a good place to spend money.

[Gary Swart]

I'd be willing to bet a profession house mover could raise the house 18" and not crack the plaster. They have lifting systems that are astonishing! Now, would it be worth the expense? I don't know, that would be your decision to make, but I think I would opt for that before digging the basement deeper and dealing with all of the concrete floor removal, making the foundation meet code, and pour a new floor. My house also has a 7' basement ceiling and I wish to God it was at least another foot higher, but no way do I want to pay the price to do it. Why people skimp on gouging out another foot or foot and a half when they are in the process of building, I'll never understand.

[shag_fu]

90 year old basements were not designed as living spaces. Thats why most are so low. The one I worked on was a small (900ft)lake cabin when it started in the 50's. Its been remodeled at least a dozen times and is now over 2k sq ft. Houses built now usually have a full height basement as its an easy way to add flexible space to a house for very little money to the builder. And it makes remodel work a lot easier being able to get to everything from underneath.

[crater]

It's NOT uncommon for someone to install a basment where a crawl space or partial basement once existed. The cost I've heard is around 30k-50k. We are blessed to have a amish community close by and let me tell ya, them boys can lift, move, straighten, you name it without cracking anything. They have become more dependant on power tools though:) Anyway if the home and property is worth it, yes it can be done, Here it is done usually to a 100yr old farm house, by probally family member, that has boughten the entire farm and is just taking over the family operation. So money is not the biggest issue if they can remodel the house where there ancesters where born and lived.

[oldielocks]

Being I am only 5 feet tall, 7 foot in a basement would be fine for me. You got to figure, too how often are you going to be in the basement? If there are other properties for sale, why not continue looking? And, put that money you would had spent in raising the house into another property maybe, of greater value?
***********************************

thanx, cookie. i am also 5'7", but i wanted to put a room down there. i think that 7' would be awfully claustraphobic after a while. i am thinking of looking elsewhere. again, thanx, oldielocks

[hj]

Interesting question because that was addressed on one of the TV shows a couple of nights ago. The previous owner, who was a general contractor. Excavated below the existing footings to add an addition. By the time the footings were shored up, along with the other repairs needed because of it the new owners were into it for about $50,000.00. And that was only on one or two sides.

[oldielocks]

thanx hj. i have now been made aware of the cost involved by all return posts. perhaps it would be much cheaper to add to existing house. perhaps, also, it might be best to look for another house!

thanx, again: oldielocks

[oldielocks]

It's NOT uncommon for someone to install a basment where a crawl space or partial basement once existed. The cost I've heard is around 30k-50k. We are blessed to have a amish community close by and let me tell ya, them boys can lift, move, straighten, you name it without cracking anything. They have become more dependant on power tools though:) Anyway if the home and property is worth it, yes it can be done, Here it is done usually to a 100yr old farm house, by probally family member, that has boughten the entire farm and is just taking over the family operation. So money is not the biggest issue if they can remodel the house where there ancesters where born and lived.
******************************

thanx, crater. all return posts tell me the costs are ginourmas. the house is only $79,000 with 960 sqft. don't think i'll invest anything. maybe i'll add on instead.

thanx, again: oldielocks

[oldielocks]

90 year old basements were not designed as living spaces. Thats why most are so low. The one I worked on was a small (900ft)lake cabin when it started in the 50's. Its been remodeled at least a dozen times and is now over 2k sq ft. Houses built now usually have a full height basement as its an easy way to add flexible space to a house for very little money to the builder. And it makes remodel work a lot easier being able to get to everything from underneath.
***************************************
thanx, shaq-fu. i have given up the idea as too expensive, as noted in all my return mail. perhaps i'll add on instead.

thanx, again: oldielocks

[oldielocks]

If you're looking at 20-30k to dig down a foot... that's about what it costs to raise a house. Definitely look into both options; sometimes raising is cheaper than digging.
************************************************** **

thanks frenchie. i've decided to bag the idea. far too expensive.

oldielocks

[shag_fu]

Interesting question because that was addressed on one of the TV shows a couple of nights ago. The previous owner, who was a general contractor. Excavated below the existing footings to add an addition. By the time the footings were shored up, along with the other repairs needed because of it the new owners were into it for about $50,000.00. And that was only on one or two sides.
Was that mike's show? I saw that too. They did another one that had a poorly poured foundation.. added too much water to the mix weakening the concrete. The gc on the show you mentioned told them not to get the home inspection which is a huge red flag in my book. bad flashing job led to a 50k basement redo. That had to hurt.

[Fistor]

Hi -

It sounds like you've already decided not to increase the height of your basement, but I thought I'd add extra argument against deepening it (I'm not a contractor or pro handyman, but I am a geotech engineer, and I deal with foundations, floor slabs, and drainage almost every day).

You do not want to excavate to lower your basement, despite some of the lukewarm suggestions saying it can be done. Firstly, as several have pointed out, you risk undermining the footings. Yes, they could be underfilled with concrete/grout (underpinning is not quite the right term here), but what you are in effect doing is deepening the foundations themselves, not just your floor.

Secondly, and probably more importantly, is the issue of drainage. Floor slabs are underlain by a drainage layer that connects to the perimeter drainage around the footings. By lowering the floor relative to the footing drains you create a local low point. Because it's already a basement, you are even more likely to collect water (from runoff, in addition to whatever groundwater table there may be).

IF you want increased height, you pretty much need to go with raising the house. As mentioned, I am not a contractor, but I believe what they would do is detach the house from the foundations, jack it up, then build in. As mentioned, may be expensive.

Anyway, do NOT subexcavate the basement floor, imho.

[Nate R]

Hi -
By lowering the floor relative to the footing drains you create a local low point. Because it's already a basement, you are even more likely to collect water (from runoff, in addition to whatever groundwater table there may be).


It IS a 90 year old house. I don't think there'd be much if any footing drain in place, much less ones that still worked.

Still, very valid points/issues to this fun thought.

[Mikey]

A friend of mine inherited a small lake home in a very trendy area of upstate New York. I guess the original cost was around $20K, many years ago. They jacked up the entire house, built an entirely new basement and lower story, and dropped the (now) upper floor back down. Cost major bucks, but the resulting home is now probably worth upwards of $500K. As I recall, a quirk in local law made this a "remodel", so tax and permitting issues made this an economic no-brainer, whereas cost-of-construction issues alone would have made it seem stupid. Also, in some areas, major additions may not be allowed, but as long as the original footprint of the house is not altered, anything goes.

[seaneys]

Unless you really like to get into plumbing....

Do you know how deep your main drain line is beneath your floor? Realize that you might be forced to lower it.

I'm 6'4 and have a 7' ceiling. It is a little tight.. Are there any beams or plumbing that is below 7'?

Steve

[Cookie]

There is a lot to be said about being short. ;), it is less costly.

[hj]

IF you do add on, depending on how large the addition is, a full basement under it might be a consideration.