# Filling a sunken tub suggestions



## Zriegel (Feb 19, 2018)

Hi everyone, I have a fun sunken tub that I have finally removed and now I am left with a hole about 2 feet deep and 5 feet long. I’m planning to level it off and install a shower in its place. Two sides are the brick exterior of the house and the other two are the foundation of the house. I’ll need to extend the drain pipe up a bit higher which is fine, but I am wondering if you all have suggestions on how to fill the hole. Dirt topped with cement since it’s indoors and will not need drainage? I would guess it would need to be pretty well compacted so there is not settling, cracking, and then cracking of the tile that will be on top. Gravel topped with concrete? All concrete? Go cheap and build it from wood?

I may be out of my DIY realm which is fine and the reason I’m checking here first. Am I in over my head since this will need to be done really well as the base of a shower that will be used a lot?

Thanks!!


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## Nealtw (Jun 22, 2017)

Sand or rock chips, compact with hand tamper ever few inches . Sand will compact if it is flooded and allowed to dry.


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## Zriegel (Feb 19, 2018)

That seems pretty straightforward, thank you. Would you recommend attaching the new slab to the existing foundation in some way?


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## Bondo (Dec 8, 2007)

Ayuh,.... 3/4"- minus crushed stone/ gravel, fill, 'n compact in 4" lifts til 4" from finish grade,....
Fill with concrete up to grade, below any tile or whatever,...
With the final coverin', it should flow exactly as ya plan,...


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## add50317 (Feb 22, 2010)

You could tie in with rebar but I wouldnt.


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## stadry (Jun 20, 2009)

*not sure i understand tieing in rebar,,, why's it ok for him but not for you ? personally i think gravity'll hold any conc in place if its not subject to frost in supporting base,,, just my opinion, tho*


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## Gregsoldtruck79 (Dec 21, 2017)

I would drill some 3/4 inch dia. bolts or rebar in to the surrounding concrete at least 3 in. deep and allow them to stick out 3 inches on 12 in. or so centers... Align them to be in the bottom 1/3 of the pour, NOT close to the top. 

Especially when using unforgiving tiles on the shower floor. If the new 3.5 inch deep concrete pour ever settles at all, then your tile will crack at the wall/floor joints. 

I have busted out old concrete pours and have seen in some places where the section of concrete with rebar in it, actually "floating" as the rock/ soil under it had settled. JMO though and opinions will vary.


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## stadry (Jun 20, 2009)

*greg's right about that,,, we've got a garage floor client who's got a 2'6" avg depth void under the conc - we think its an old bldr's trash pit,,, only thing holding up this cracked floor is compression & luck*


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## add50317 (Feb 22, 2010)

stadry said:


> *not sure i understand tieing in rebar,,, why's it ok for him but not for you ? personally i think gravity'll hold any conc in place if its not subject to frost in supporting base,,, just my opinion, tho*


I assume you are talking to me...IMO I wouldn't. You rebar driveways and garages and roads not shower stalls. But what was mentioned about a space under concrete...sounds like rebar IS a good idea for settling reasons. I would just prep the area really well. Thats what I would do.


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## stadry (Jun 20, 2009)

*primarily rebar adds flexural strength in bdge decks & driveways,,, little bit of compressive in columns,,, d/w's, more importantly, need a proper joint pattern installed at the correct time,,, just my exp*


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## lenaitch (Feb 10, 2014)

No suggestions, just curious. You had a bathtub at an entrance door? Was it like a footbath station?


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## Zriegel (Feb 19, 2018)

Thanks everyone for the ideas, I think the fill won't be too bad. The 1.5 inch pipe is another story...

Lenaitch, the door is an exterior door to the backyard. The master bedroom has this bath attached at the back of it and the door out to the back of the house.


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## Shellback'00 (Feb 21, 2018)

Interesting tub. I've honestly never seen one like it. Curious if this is overseas. I would think in the USA it would be some kind of liability risk?


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## Zriegel (Feb 19, 2018)

Phoenix, built 1979 by a crazy person apparently.


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## wcthurston (Feb 18, 2019)

Zriegel.....how did this turn out - lessons learned? I am about to undertake a very similar project - filling in a sunken shower. Any info would be greatly appreciated. 

Thx...wt


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## Zriegel (Feb 19, 2018)

Hey wt, I ended up filling it with I believe 3/4 minus as someone suggested. It was gravelly with basically dirt mixed in. It compacted well by hand, I compacted about every foot until I was 4 inches from the top. I did end up tying it to the house slab with 2 or 3 small pieces of rebar. Covered the last 4 inches with concrete which it turns out I suck at. This left a pretty rough top layer that I ended up having to smooth out with a bag of self leveling concrete which actually worked really well. That did the trick and the shower has held up well so far!


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## flyandbike (Nov 19, 2021)

Zriegel said:


> Phoenix, built 1979 by a crazy person apparently.


same thing in my parents home in Phx. It was a popular idea, then.


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## fspecial (3 mo ago)

Zriegel said:


> Hi everyone, I have a fun sunken tub that I have finally removed and now I am left with a hole about 2 feet deep and 5 feet long. I’m planning to level it off and install a shower in its place. Two sides are the brick exterior of the house and the other two are the foundation of the house. I’ll need to extend the drain pipe up a bit higher which is fine, but I am wondering if you all have suggestions on how to fill the hole. Dirt topped with cement since it’s indoors and will not need drainage? I would guess it would need to be pretty well compacted so there is not settling, cracking, and then cracking of the tile that will be on top. Gravel topped with concrete? All concrete? Go cheap and build it from wood?
> 
> I may be out of my DIY realm which is fine and the reason I’m checking here first. Am I in over my head since this will need to be done really well as the base of a shower that will be used a lot?
> 
> Thanks!!


Hello,

I'm remodeling a sunken shower here in Florida. The house is on a concrete slab, and the shower is sunken into the slab. The dimensions are 70" L x 35" W x 10" D (17 SQ FT). I'm thinking of just extending the drain and pouring concrete with no rebar.

What did you end up doing and what are your thoughts on this?


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