Anyone ever raise a sunken floor?

[Van]

My fathers house has a sunken living room floor which for a slab house sitting in a flood zone 15 minutes from the ocean front and the house itself sitting on a canal was probably one of the stupidest idea's the developer had. The room is 19.5' x 12' x5" and what I want to do is raise the floor because it has cracks allowing the ground moisture to seep in during times like this when the ground is saturated to max levels. Installing a wooden sub floor is out of the question as it wont solve the water seepage issue so I know that I need to pour concrete but what I'm wondering is if I need to break up the old floor or would I be able to pour in a 5 inch depth and if so what would I need to do to the existing floor and the concrete riser ( correct term for the supporting wall from the sunken floor that goes to the main house floor? ).

Thought I would ask here as I think I remember someone saying that they have done cement work in the past or may have had to have something similar done, I may also look at ambient floor heating as well.

 

[JimMcC]

You really need to talk to a qualified contractor or carpenter. Are you looking to make it the same level as the adjoining room? Is there a patio door or anything in the way from doing that?

 

[Van]

Basically I'm raising it to meet the same level as the rest of the house which is currently 4 inches above ground level. The living room has no patio door and only one window that will be remedied in the future as it is to dark in the living room now.

I know that I need to talk with a professional and I thought we had someone involved in the concrete business here on the site or had had something similar done at one time so I check with people I know.

 

[Ramy]

If the floor is broken up. I would say your best solution is to tear out all of the floor and repour making sure to put down a barrier to keep the moister from coming up through the concrete.

 

[dewzan]

first repair concrete seal with a good epoxy, resin paper, rip green treated 2x6 to 41/4" , add spray foam insulation (to deaden sound) add 3/4" floor deck and there is your 5".

 

[truckracer]

i thought about "mud jacking" where you drill a hole in the low point or various points pumping a slurry of mud and concrete to lift it. as far as waterproofing...i am with the sealer and epoxy. sounds like the location of the house is going to be a real challenge.

One idea may be in the low spot to digg and pour a sump area to place a pump with a level switch that will pump out the water from under the cement when it build up.

leave an access cover under the carpet or wherever so you can lift up the cover and replace or check the pump periodically. you will need to run power and a pvc pipe to the pump to get the water either in a drain somewhere or outside the house.

you would have to jackhammer a couple of long runs to install some perforated pipe and pea gravel that leads to the sump pump box.
then fill cement back over the pea gravel and pipes.

that would drain and relieve any accumulated water away from under the concrete slab and when the water would rise to a level in the sump pump area a float switch would turn the pump on taking the water out.
check with a local contractor and see what they think...i am not sure in your situation that just sealer is going to do it.

 

[Van]

I'm thinking that a sump won't work given the constant ground saturation that we have had because it would cause the pump to run near constantly. I have been looking into putting the perforated pipe out in the yard to drain water out to the canal and to the street but the floor will either have to be filled in with additional concrete or completely redone and brought up to the same level as the rest of the house. I'll also have to install gutters with self extending and retracting pour outs to direct as much of the water away from the. Keep in mind that the water table sits about 2 - 2.5 ft below the surface on normal days and it gets higher when it rains for more than a half day or during heavy downpours.