I have attached a picture of a hole that we have in our concrete slab in our bathroom. [ATTACH=CONFIG]34816[/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.

Thanks

 

surprised no one's responded - yep, you're right - set the drain @ correct elevation then place bagg'd conc mix - 1 80# b = 2sf @ 4" but expect a bit less yield - good luck !