Partial Basement In Florida?

gap

Hello all,
First off I'd like to thank everyone for the good advise I've found here on projects I've tackled which--at first--I knew nothing about. I know have another which I couldn't find any threads to advise, so here goes my first--

I have a sloped piece of property which I plan to build a house and shop for my business. My first idea was to heel the house partially into the slope with say a 10' high stem wall on the three sides dug into the slope. On the front side, the wall would be about 3' above grade and on the back at grade--although still sloping. The whole basement area would be the shop will roll doors on the back (grade side). The one story house would sit on top with a step-up front porch. Are there surefire methods of waterproofing such a setup? I'm betting this is why I've never seen a basement down here. If there is, how would the cost of this compare to just erecting a separate metal building--say 40'x60'. I really don't like the looks of metal buildings, but like water problems even less. Since I have more slope--the means to drain water away from around the stem wall and away from the house I'm wondering if this might be feasible. Sure would be nice to walk downstairs and be in the shop. Any advise would be greatly appreciated.
Regards,
Scott

Teetorbilt

gap, Where in FL are you?

The reason that you don't see many basements in So. FL is because, in most places, you are only a few feet above sea level or the water table. My current home is over 14 ft above sea level, it's the highest place that I have ever lived in this state, my ears pop on my way home. LOL

You need to contact someone who knows the hydrogeologics of your area. Be sure to ask about catastrophic events such as what happens if you get 25 ins. of rain in a week or two.

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PipeGuy

The slope of your lot makes for relatively easy, and reliably effective, waterproofing of the structure's lower level. Proper wall construction + intact exterior moisture barrier + vertical drainage membrane + well placed and daylighted foundation drain + well placed wall backfill = dry basement. The expense will be a small fraction of the cost of erecting a separate metal building--say 40'x60'.
Search the site for 'waterproofing', 'foundation', 'basement', etc. There's been much discussion.

kenvest

the only high ground i saw there was the landfill in Jacksonville....

gap

I'm in Gainesville. The lot drops 50' over 1000' into the swampland of Paines Praire. The building site is near the top of the slope. Clean sand as far as the post-hole-diggers can see. The parcel across is 240 acre preserve/horse field which is slightly higher then my lot. During (I should say right after) the storms last year I did notice the water table was a few feet below grade at the building sight. By digging a hole you could actually watch the water running thru the sand down the slope. So I know this will happen again. I'm just wondering if it's possible to do everything possible to seal the slab and stemwall, then french drain the heck around the three sides to carry the water around the basement and down to the swampland. How risky would this be and what would be the best method for sealing? I can't get the visions of driving around the back of the house to a tucked away four bay shop out of my mind. Am I crazy?
Scott

Glasshousebltr

Been to that dam landfill, Toooo many times.

Gap, it's called a walkout, the project design your considering. Waterproofing? yes it is freezable, however as Pipe pointed out, better get a local pro.

Bob

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Bob

ContractorSon

That is a very shallow slope over such a long run.Lived in S Fla,now NE Ohio,and now have a walkout basement. Our lot falls 7 feet over a 40 foot run (front of house to rear),and allows for 4 foot high windows,8 ft ceilings, and a 7 foot high sliding door across the back.
Next home will have 10 feet celings in basement.

You can often "fudge" a daylight basement with excavation,but difficult to get a walkout (or in your case,a drive in). I would say find an area that has 5-6 feet in a 40 foot run and you may be able to dig it out. Maybe a high ridge where the scrub Oak trees stand.Sometimes a "side walkout" may be easier as the "valley" area is narrower than the entire back of the home.

PipeGuy

That's a great point. While 50 feet in a thousand (5 in 100, 2 in 40, 5% grade) is more than enough slope to assure good drainage, it requires 140 feet of run to produce seven feet of drop off. That'd be one deep house.
A 35 foot deep house with a 10 foot basement needs to have a first floor that's more than 8 feet out of the ground, at the front door, to accomodate a lot that flat.

gap

Thanks for all the input. The building site does have a steeper dropoff--I'm guessing 6-7' over 20'. I was planning on spreading out the excavation sand in front to give the house the appearance of sitting on top a small hill? I'm hoping this will also help to shed any surface water away from the house.
PIPE: I was planning on doing all the sitework and subbing the rest. Your equation seems right but was wondering if you could expand on it a bit--what's the best technique for each phase (CMU vs poured walls/most reliable coating products/underslab treatments?). When talking with various subs, I've found everything--price/quality/etc. seems to be much better when I at least give the impression of being familiar with the options and techniques of the trade. Before places like this were around, free advice was hard to come by. The questions I ask here had to be asked to the people wanting to make money. After those meetings, many times then I felt like I was wearing diapers and holding a bunch of candy ready for the taking...
thanks again all,
Scott

ContractorSon

WarmNDry insulating board by Owens Corning/TuffNDri exterior sealing compound by Tremco (RPM).
We have a poured wall right now,but will go to 12" block for the next home due to the number of corners and short wall outcroppings.
Is it all sand where you are?
Have fished the Ocala National Forest,and remember very fine sand,vs. the muck found elsewhere in the state.
Have you done soil testing? (also Perk Testing for septic?)
That may determine the system you need to use...

In Ohio,the clay does not drain well and provides a lot of lateral forces/hydrostatic pressure to the basement walls.

gap

Thanks CS, I'm guessing I'm on a pretty deep sand hill. I haven't yet fully cleared the property yet. Few months ago spent a day with a bobcat/rootrake and did some--I'm still sratching weeping chigger sores. Decided to wait for cool weather to continue. Probably picked a bad time to build. I'm helping my father-in-law build a house in Crystal River--8' CMU stem wall at $4.00/block--brutal. Now we're scrambling trying to get the wall filled before WILLLMMAA (can't keep but thinking of Fred on the Flinstones on this one). Time to batten the hatches again.
Scott