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The pit under the tub!

1500 Views 8 Replies 5 Participants Last post by  Maine1
Just removed the access panel for the plumbing on our downstairs bathroom. ( split level home on concrete floor built in early 60's)

I found the hole in the concrete that the plumbing sits in. It looks like it would have originally been a square hole anout 2'x2' with plywood walls and dirt a the bottom. It looks like the tub drain seal has been leking for quite sometime, it drips when the tub has water in it. The hole is filled with what is left of the old plywood walls, all rotton and practically powder. The dirt has eroded away from one side and you can see it goes under the slab . Hopefully you can see it in the pics.

I am going to fix the leak but should I be concerned about the condition pf the pit? It smells funky but you cant smell it with the acess panel in place. I dont want to stir anything up but the debris in there is probably harboring some nasty stuff. Is it best to just leave it be and keep it covered? With the leak fixed maybe it will dry up.


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Get rid of the wood spray area with bleach should be fine as long as you stop the leak.
I just realized that maybe all the moisture from this hole was the cause for the rotten/moldy wall that seperates this bathroom from a bedroom. I originally thought it was from a toilet leak or sweating pipes but maybe not. I have since repaired and finished that wall.

I will try and clean out as much debris as I can from the pit. Should I put anything in there like gravel or anything, or just leave the dirt exposed.

Also, is there a possibility of ground water coming up through this hole causing excessive moisture in this area?

I just dont want anymore mold growing in this area as it will be my daughters room.


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Sorry but I Just wanted to bump this post because I want to do the right thing with this but not sure what that is... Im just worried about the potential moisture from this and how to manage it.
Just my thoughts on this is, once you have the leaks stopped and have given it time to dry out good, place a sheet of plastic over the hole and let it sit for a day or so, then check to see if any moisture is on the plastic. It may take a good while for that to dry as it has been leaking for a good while.
The studs and plate are getting wet from a leak where those clips are that hold the surround and the tub together, not that hole. Look at the water traces on the back of the surround near the clips.
I did see that, although it is funny how obvious it looks in the picture but in person it wasnt so. I have caulked the seam on the other side hoping that will help there. There is still alot of moisture in that hole from the tub drain shoe seal leak. There is alot of wet debris in that hole from previous work being done like old drywall peices wood and other scraps.

Once I clean that debris out I am left with wet dirt... In that enclosed space, I dont know how long it will take to dry out. Should I put anything in there over the dirt like gravel or something?

Thanks for the advice
You've got several issues going on there. IMO, to do this right you need to cure the leak in the panels, replace the tub waste and overflow with a pvc or abs glued assembly. Then replace what appears to be a drum trap with a ptrap. I'd consider going a step further and replace the copper dwv piping in the hole.
After all that, tackle the mold/moisture issue in the framing and hole.
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Good advice, thanks. I will replace the tub waste like you suggested. Unfortunately, I cant get down far enough into the hole to replace the copper and drum trap at this point. I would have to gut the bathroom, which might be where Im headed but not at this tme. Maybe in 6 months or so.

I have already replaced the rotten framing on the wall in the pic. That wall is now fnished and painted. I am hoping that caulking the seam inside the enclosure will help for a while and fixing the active leak at the drain shoe will also help. When I repaired the rotten wall, I used a pressure treated plate with a foam barrier so hopefully that will keep any more rot away for a while. I will keep my eye on the inside of that wall through the access hole for the time being.
Should I put anyhing in that hole in the meantime?

Also, when it comes time to remodel this bathroom, how do I deal with this hole in the slab? Should it be left there or can it be filled in with concrete once I replace all the plumbing?

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