extremely low clearance crawlspace

Hi All,
We just purchased an older townhouse (1910) with a small kitchen addition. The main part of the townhouse has a small basement under it, but the kitchen had what we could see from the basement was an extremely low / no clearance crawlspace. The kitchen floor was very spongy, so we suspected rotted floor joists and/or water in the crawlspace. We tore out the subfloor to confirm.


The far side of the room is just slightly below grade, which is why there is a step up to go through the doors there. It looks like someone tore up the subfloor once before and put bricks under some of the joists and sistered one of them with 2x4s. The sistered joist is completely free of the foundation and resting in the mud. There is a lot of plumbing there and some of it runs to the bathroom (through the door on the left), which we hadn't planned to modify. The back patio actually seems to drain really well.

My first thought, which may be crazy, is to remove the floor joists and debris, maybe add some kind of drainage system, and then pour a concrete slab. Anyone have any insight or experience to offer regarding that or some other solution?

TIA

ETA: We would like to move the sink to the opposite wall - to the right of where the photographer was standing

 

Wow, so my first thought is what kind of perimeter foundation is in there? Addressing the floor but not addressing a possible foundation issue isnt going to be a long term solution!

 

You added details based on a picture ?

I don't see any pictures which makes it difficult to offer helpful information.
How to insert pictures.

 

Have you taken out a building permit for this work? This is very major work and are borderline for a teardown and rebuild.

Pouring a slab is a good idea. I hire a building moving company, or try it yourself, to cut that part of the building free. Then jack it up so you can work on the foundation below. You'll have to excavate for footings and pour the floor with your new drain plumbing installed. Then you can install a new pressure treated sill plate and set the room back down on top of it. Or, it may be faster and cheaper to tear it all down and do new construction.

 

Thanks for the responses, everyone. Sorry for the slow reply, but I wanted to do some investigating before coming back.
PJmax When I load the thread I can see the picture, which I think I inserted according to the directions. Are you able to see it now?
Marq1 Silly me, I just assumed there was a worthy foundation under there, and thought we could pour gravel and concrete between the foundation walls and call it a day. I went back after reading what you all wrote and did a little digging next to the two side walls. It was not great. The left side abuts the neighbors' brick wall, and under the wood framing I just found soil and then a few inches down the footer for the brick wall. The right side is more complicated. Part of it (about 4 ft) is resting on a basement extension that protrudes under the room - maybe originally it had a stairwell to a storm door? Poking a shovel into the mud under the rest of the wall I found several places where there wasn't anything but more mud, and then a spot near the far corner where there was something that might be a cube of concrete. The far wall where the door is seems to be in much better shape, and the wall itself seems to start near ground level, rather than below it on the sides, so I think there is some kind of foundation there and that is supporting a lot of the weight of the roof, but now that I write this I'm not sure why I didn't do any digging there.
Pilot Dane - We did get a permit for the demolition, and will get one for the construction work once we know what we want to do. Disconnecting from the rest of the house and jacking it up...damn that sounds like a lot of work. I think I'm going to have to call in a foundation repair company, but I'm wondering if it's possible to repair/build a proper foundation in sections, without lifting the room? I think I've seen pictures of people doing this, with the wall above temporarily braced.

If I was going to do foundation work anyway, it might be better - instead of concrete - to build a foundation up to above grade, closer to the height of the two doors, and then build a new wood floor over that?

 

With such a major repair now is a good time to consider all your options. The Building Inpsections Dept is going to require footings. This work can be done with the house in place but can be more difficult and slow because the house is in the way. So, investigate multiple options and see which is right for your project.