Shower drain concrete slab issue


Old 07-15-14, 04:42 PM
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Shower drain concrete slab issue

I have attached a picture of a hole that we have in our concrete slab in our bathroom. [ATTACH=CONFIG]34817[/ATTACH]

I've just taken out an old ceramic shower from my bathroom and will be installing a new walk in shower over this area with the hole. The hole is about a foot and a half square. We'll be using one of those pre-fab shower bases like KBRS and then tiling over it (the shower base will be about 3.5 feet by 5 feet.

My question is, do I need to fill in this hole with new concrete or will the shower base be solid enough that it can rest on the existing concrete without a problem.

If I do need to fill it in with concrete, what is the best way to handle the shower drain (which will be replaced)? I was thinking of installing the base of the new drain before pouring the new concrete and having it just above the level of the concrete (maybe a quarter of an inch) so that I can put in some self leveling material after and have everything flush.

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Old 07-16-14, 03:50 AM
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IMO it should be filled with concrete although I've been on a few jobs where they just filled it with gravel but I'm a painter - wait and see what the others say
Old 07-16-14, 06:08 AM
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Even if the instructions don't give a clear answer I would fill the hole. Concrete would be best but you could probably also use thoroughly compacted stone/gravel. I don't like leaving any part of a shower pan unsupported and especially not the drain area. Any slight movement between the shower pan and drain pipe could eventually cause it to leak so I want it rock solid.

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