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Discussion Starter · #1 ·
I am considering setting up my basement for and entertainment area including a screening area. The only problem is that I only have 7 feet from floor to ceiling joists due to a sunken family room above. Lets start some dialogue to know what all is entailed/has to be considered in digging out the basement. The total area that I would consider digging out is 15 by 20 (part of a much larger area) however there are support poles that line the outside of this area. So the question is what has to be considered to ensure a water tight sunken floor as well as ensuring the structural integrety of the house. I have notice numerous times in the home page where people have excavated to give them head room. One thing that is available is a walkout 10 feet away where malterial can be dumped into a gulley.
 

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I've read a few of the threads where this was done so that coupled with watching 3000 episodes of This Old House makes me an expert.


first random thought is the support beams should actually be sitting on much deeper concrete pads than the main floor area. I think they are typically 2x2 in area and what ever you do these things need to be avoided at an appropriate distance. OR


I suspect you could actually dig down and pour new foundation pads and use longer support poles and then conceal them in a wall.
 

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how much does it truly cost ot excavate?


People laughed at me when I said I wanted to put a basketball hoop/gym in my basement and I would have to excavate to get the right height. They said it would cost me 75K.


I would do 20-30K....it's a dream for me to be able to shoot hoops year round in my house. Wuld be awesome to go into my basement, but then open a door to a small gymnasium with a hoop!
 

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I too have a sunken living room above my second H.T. and it is truely a hinderance to my plans but I do have 8 1/2 feet to ceiling.
 

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My entire basement is 7ft and im perfectly happy with it and that includes the theater room. Im only 5'9" so im not bumping my head, but I do have low areas for hvac that are 6'2". I would love to have an 8ft or 9ft ceiling, but im happy with what I have. Just make sure if you decide to it, then it will be worth the money. I cant see this costing less than 15k-20k for that size of a room.
 

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Discussion Starter · #6 ·
One thing that would save a ton of cost is that I can get a dingo in the door which is 10 feet from the area I would be excavating. It is a thought of mine as I begin the process of thinking about placement ofeverything. I wanted to get some constructive feddback of things to consider when doing this.


Maybe I should call 1-800 got junk and tell them I have some concrete and 3 feet of dirt that needs to be removed from my basement.
 

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how much does excavation truly cost?
 

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The excavation is the cheapest part of the build. There's a couple of forces that are in play when 1) remove the floor 2) remove the soil beneath the footings.


Your basement floor serves as a "lock" so that the hydrauic pressure exerted from the backfilled walls don't push the walls in at the bottom. Of course a lot depends on the height of the wall and how much is removed from the footings. There is a method available similar to pinning in which the footings are stabilized and the lateral force is compensated.


As I mentioned before, the digging is the easy part- get some laborers and carry the spoils out in buckets. Now you'll need to get your base put back in, assuming a good soils report, place your undergound in that you hit when you dug out the floor, bulkhead in the footings, and pour the floor either with buckets or through a window well in your basement. Another thing, try to vent out the basement just to get rid of all that moisture that's going to gas out from the concrete curing. Depending how much is to be removed, it may behoove you to have an engineer take a peak at what your looking to do.


One more thing, there is nothing neat about this work, so as much protection that is put on the floors/stairs and walls is to your advantage. Its doable, but very labor intensive, especially if access is limited.
 

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OK let's say I wanted to build a gym underground that housed enough room to shoot 3 pointers (22-25 ft) for a basketball hoop. That means the roof has to be tall.


What is the price?


I've heard of people doing this "under the garage" or "under the driveway" etc. My basement is already finished and is only 7-8 ft ceilings.


So any guesstimate on price?


-ELmO
 

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ONE MEEEEEELLLLION DOLLARS!!!
 

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You do not need to dig out the entire room, the back row could be at the existing basement level with your other row(s) dug deeper into the room therefore reducing the amount you need to dig by about a third or more. I have no idea how other foundations/groundwater/tie-ins/floor drain or other items would effect your decision. Are there any lines running under where you plan to dig? Sewer would be a to move.
 

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Cost is on a per job basis. There's not a sq.ft. price to go by- the more footage done, the less the sq.ft unit cost. Things are slow in the resi world, so maybe pick the brain of a legitimate company in your area and see what he has to say, can't hurt. When you venture into the construction world, all contractors are not created equal. Ask around and you'll see a patern of good ones and not so good ones.
 

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That makes sense as I have gotten estimates that are nowhere near each other (lol).


Yes I have sewage lines probably close as I have 2 or 3 manhole covers in my yard alone (funk!). Trying to stop my dreams from coming true!
 

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Well, digging down a foot to give 8' of headroom instead of 7' is one thing. As mentioned, you will probably still be above the tops of any footings.


Digging down 10 feet or whatever it takes to have a basketball hoop would mean having dig all new footings or somehow shore up the existing footings before you dig or as you dig. Anything is possible, but the costs for 10 feet of digging I could easily see being the $75k people mentioned - or more considering details of your situation.


I am a commercial general contractor, not residential, but I have priced stuff like this into projects before, like shoring up sections of a wall to then run a crapload of electrical or communications duct bank into a building. One project used helical piers, like they use to fix foundation issues and we hung the section of wall off those with a steel bean running accross. Then the wall was cut out below that. THE piers were about $8,000 total for 3. The rest of teh work was another $10 $15k IIRC, and that was just to get a 10 foot section of wall ready so the electrical sub could come in and do the actual work under teh wall, no excavation included.


IMO, you would be better off and probably cheaper having a small garage addition put onto your hose with plenty of headroom. THen just back the car out when you want to shoot baskets.
 

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Not enough space in the side yards (I think we have only 15 ft of side yard on each side). Got about 40 ft in the backyard, before it hits a pond..


That is amazing to me that excavation costs that much when many houses themselves don't cost that much. My home is valued in the low 200s (bought it for 255) - it's just amazing excavation is 100K of that.


Very easy for someone to take advantage with "a K here", "5K there" - and pocket it.


-ELmO
 

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Elmo,


The cost to excavate for a new house is very small relative to the overall cost of building a house. The reason it would cost on the order of 50k-100k to create a deeper basement in an existing house is because there are so many restraints and precautions that must take place to ensure the foundation walls and soil will not collapse around you while doing the work. You have to remember you have the full weight of a house above you exerting pressure on the soil below the footings you are attempting to excavate below. A significant amount of cribbing and shoring is necessary to prevent your house from collapsing. Also, the logistics of tearing out concrete and hauling soil in a tight space makes it much more time consuming compared to a large backhoe with unlimited space around it to move dirt for a new house.
 

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What about ripping out the driveway and digging under it, then replacing the driveway? Does that still disturb the foundation?


Our driveways are fairly small, probably less than 18-20 ft long.
 

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I believe your dream of basketball in your home is not going to happen at that particluar home location, unless you go with a little tikes hoop.
 

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Damn you!
Do you only have REALISTIC dreams?


Check out this home gym (rhino courts did it):




I'm having Rhino Courts do a putting green in my backyard this or next year, it's roughly only 4K - but that is obviously a much different endeavor.
 

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Not in regards to the basketball, but in regards to the OP's question.


Sunken living room - is there anyway to raise them or would that be more costly than digging out? Just wondering as I have no idea. In our house we have a sunk living room, but the ceiling is way high as is. Raise it 1ft and it would be fine........
 
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