View Full Version : Basement shower
01-06-2009, 11:17 AM
About 3 years ago, I had my basement bathroom finished. There was a hole in the concrete floor approximately 1 foot x 1 foot to plumb the shower stall to the sewer line. The contractor set the shower and plumbed it, but did not fill the hole in with concrete. Should I be worried about the hole under the shower, or just consider it water under the bridge for now? Thanks.
01-06-2009, 12:16 PM
Why didn't he fill the hole?
Do you have a shower receptor there now(fiberglass) covering the hole?
If it's a shower receptor that means it's hollow underneath and lacks support. I always put shower receptors on top of a base so it doesn't flex when walked on.
To remove the base after the tile is done is a lot of work. If no sheetrock is done and the base was just installed it's very easy to remove it, fill the hole, and set it in something like structolite so it's well supported.
01-06-2009, 01:02 PM
It is a full fiberglass shower stall, and the floor seems to be supported properly. It is totally finished now. However, the right wall is a partial wall with a toilet on the other side. If necessary, the bottom part of that wall could be cut out to allow access underneath the shower.
01-06-2009, 05:19 PM
If the hole underneath the shower receptor is not causing any flexing when you step into it, then it should be fine. I can't think of any reason why a little space under the shower receptor could do any damage. Wait for others to chime in.
In my opinion, just leave it alone for now, if there's a problem then you could open the wall and fill the hole. There's no sense in doing it now if everything works fine.
Next time, always bring up concerns during the construction process when it's much easier to deal with them. Because once finishes start to go up it becomes much more difficult.
01-06-2009, 05:49 PM
If the base is not supported well, over time with use, with each flex, you are liable to fatigue the glass fibers and allow it to flex more and more. Eventually, it could fail but prior to that it will start to feel softer (since it won't have as much strength), and micro fractures start to show up that will look like it is getting dirty (well, it is - dirt is getting into the microfractures). If this ever gets extreme, it can cause the seal to fail or it will crack all the way through. It is a really good idea to support the base well during the install with something. Ever leaned against a corvette's door or fender? It will only oilcan so many times before the paint fails (like the gell-coat on your shower). the better ones are well supported, but it still doesn't hurt to support it well in the gaps.
01-06-2009, 11:31 PM
Fiberglass stalls that I am familiar with require a bed of mortar under the base. It doesn't have to be solid, you just put in piles then set the base on them while they mortar is still soft. The peaks in the piles will squish out and leave plenty of mortar support. You could also chuck some mortar in the hole around the drain to firm it up.
01-07-2009, 06:53 AM
I guess my big concern is moisture from the hole causing problems with the wood studs and insulation in and around the shower. We have lived in the house for 5 1/2 years, and up to this point, there has never been any moisture or water problems with the block walls or concrete floor. The hole was open the first 2 1/2 years that we lived in the house, and I never noticed any water or critters in it. I am probably just worrying too much about something that is not an issue.
01-13-2009, 06:51 PM
There is nothing to worry about until there is a problem, which is unlikely. It is far too much work to tear it all up just to firm up the base.