# Concrete Slab home; void under bathtub



## thegogetter222

Hey guys, just bought my home this summer.  Any idea why there's a void (visible through the tub access panel down to the dirt) under the bathtub while the rest of the house is concrete slab?  I see at least 1 joist that is completely rotted.  The bathroom is full tiling.. floor and walls with jacuzzi tub, very nice.  I'd hate to rip it up... just wondering what your thoughts are.

Thank you!


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## nealtw

Not sure what joist you see. That hole the concrete is pretty standard, it allows room for the trap under the tub.


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## thegogetter222

yup... that would show my humble position of novice : )   The joist I see is the supporting joist that goes under the center of my bathroom all the way to the wall.  In fact, the "void" fills with water in heavy rain... which is a whole other drainage issue I have to address in the spring.

Hmmm... thinking... I need to see if I can in fact see the concrete slab from within the hole.  I'll need to use a mirror, but I should certainly see it not to far off, right?


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## nealtw

Maybe I just missunderstude, here if you have a slab house, you live on a concrete floor. If you have floor joists, you should have a crawl space? Anyway the water there is a problem.


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## thegogetter222

ok, I've posted 2 pics here on my picasa: 

https://picasaweb.google.com/thegog...&authkey=Gv1sRgCKTaz8DLnJOwcw&feat=directlink 

Pretty bad rot... not too sure what to do about it besides proper drainage on the outside of the house then eventually a bathroom remodel


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## nealtw

You need to sove the drainage thing and open the floors around the house and dry this out properly.


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## BridgeMan

Homes built on slabs do not have floor joists.  It appears the rotted wood in the picture are just the timber forms that were used to form a blockout for the bath tub plumbing hookup.  Not totally uncommon, but forms are usually removed prior to tub being set.  That looks like an after-market whirlpool tub, too.

Once you get the outside drainage issues corrected, you might want to make an effort to dry out the rotted wood before it starts to smell, or grow nasty little critters that like to roam the halls at night.  Eeek!


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## thegogetter222

awesome, thanks guys : )
I know I have a drainage issue that needs to be addressed sooner rather than later.   

all the best


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## joecaption

I also live in a slab home that the slab was pored to low.
I had to add a french drain around the whole house. I also added a second line (4" sch. 20 PVC) and piped all my down spouts into this pipe and had to add a pit with a pump in it because there was no grade for run off.
While I had the footing and block exposted I sealed the foundation with foundation sealer.
Once this was done all my mold and water problums went away.
The total cost was only a few hundred dollars because I did all the work myself. The biggest cost was the new sump pump.


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## thegogetter222

interesting... thanks for the info.  Do you have a dry well?  where does your sump pump the water too?  i was thinking about auguring a dry well for this process.

On a different note or post even:
I also do not have any grade to route with.  All my gutters, 2 front driveway drains, and 2 internal garage drains, already run into an underground pipe that runs the perimeter of my house, but I CANNOT FIND WHERE THE WATER RUNS TOO!  I have tested it with the hose, listening to my septic with the lid off and no water or noise.  I literally have no idea where this water is going.  Any thoughts on this issue?  wowsa!


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## nealtw

Sound like all that water is going under the bath tub. You need to stop the driveway water and roof water away from the house.


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## BridgeMan

The home builder may have piped everything to a remote drywell.  Does your yard have any areas where the grass seems to always be greener or grow faster?


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## nealtw

You want to map the dist. field for the septic before digging a dry well, you wouldn't want to overload that area.


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## thegogetter222

First of all, thanks for your time trying to think this through with me.  

This wet ground (other side of the tub void) is about 10ft from my septic lid and no grass is healthier/greener than the rest.  I'm pretty sure I know where the field is though and its not be in an area where i would be considering to work.  This is a very tight spot where its generally saturated and it just so happens my gas and electric lines are routed about 10ft the other direction... so septic on one side and gas/electric on the other with about a 20-30ft in between.  I can split them down the middle and go 50' straight to the woods where theres a slight grade once you get to the treeline to the forest floor.  That is where I was thinking the drywell could be.

The drywell is just an idea for now... trying to figure out how to drain this standing water with zero grade.


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