Shower or bathtub in basement

[JWG]

I am refinishing my basement. The house is approx 8 years old and I am told that there is a shower drain under the concrete. My first question is, how do I get to the drain?

Second, the walls in the bathroom leave approximately 12" behind the drain and 12" to the left due to another wall. I have 58" from the left wall to the right and plenty of room in front. Is there a standard size shower (or bathtub) or minimum rough opening size that I will need to fit eiher a shower or tub into a space? Any information would be appreciated. Thanks.

[LazyPup]

Normally when a drain is provided for future use it is stubbed up close to the finish floor. Sometimes the concrete finishers will be a bit off grade cover the stub up. It would then require a thin breakout to find the drain, but you would need to know where it is before beginning the breakout.

I have prepared an illustration of code minimum dimensions for a shower floor pan. Commercial ready made floor pans will be set up for the drain in the center but a field made floor pan could be made to allow the drain to be a bit off center.

The floor of the shower pan MUST BE pitched a minimum of 1/4" per foot and not more than 1/2" per foot in the direction of the drain from all points.

The shower pan must have a minimum of 1024Sq.In. (32" diameter and a minimum of 30" diameter from back wall to the center of the door threshold. IRC2708.1 & UPC 412.7)

The minimum interior dimensions must be maintained until 70" vertical above the finished drain (IRC2708.1 & UPC 412.7)

Shower heads, mixer handles, grab bars & soap dishes may proturde into the minimum space. (IRC 2708.2 & UPC412.7)

Shower walls must be water tight a minimum of 72" above the finished drain (IRC 2709>1 & UPC 401.1)

Shower valves, shower riser and shower head MUST BE secured to a permanent structural member (framing) (IRC 2708.2 & UPC 412.12)

Door -Min. 22" and must open outward (IRC-N/A & UPC 412.6)

Shower head MAY NOT discharge directly toward the door (IRC 2705.1 & UPC 412.11)

A listed anti-scald/pressure balance valve req'd at 120 dgF max. (IRC 2708.3 & UPC 420.0)

[JWG]

I have broke out the concrete and located the pipe, however it is simply a 2" pipe going over to the sump pump. There is an 8" cardboard surround that they used to put the concrete over. How do I go about getting a p-trap connected to this 2" pipe? I realize I will need to dig out enough dirt to get the p-trap connected, but how do I assure a clean joint and how do I go about digging down without having dirt fall in the hole from outside the cardboard piece? Thanks for any further help you can provide.

[LazyPup]

You have located the pipe but this now introduces a couple new problems. You know that the downstream end of the pipe is connected to the sump pump pit, but what is the upstream end connected to?

The second problem is that a sump pump pit may only receive storm drainage. You may not discharge a shower or other sanitary waste into a sump pump pit.

In a situation where a drain is required below the main gravity flow drain you may install a "Sewage ejector pump system"

A sewage ejector pump system is similar to a common sump pump, except:

1.A sewage ejector must be installed in an approved receiver vessel.

2. The lowest line discharging into the receiver must be a minimum of 2" above the pump "start" level.

3.The receiver vessel must be equiped with a water tight removable cover.

4. The receiver vessel must be equiped with a 2" diameter vent.

5. The sewage discharge line must be a 2" diameter waste line. (1-1/4 is okay if the sewage ejector pump is equiped with a mecerator grinder)

6. The minimum capacity of the pump must be 20 gal/min.

7. The sewage discharge line must lift to a point above the gravity flow drain to which it is connected.

8. The discharge line must connect to the gravity drain line by means of a WTE fitting, with the side opening of the Wye on the Top of the gravity drain.

9. The vertical lift discharge line must be equiped with an automatic backflow preventer.

10. The vertical discharge line must be equiped with a gate valve.

To connect the P-trap you will need to continue digging out the hole until you have enough space to work. You may have some dirt fall back in as you dig, but that should be minimal and you will be able to dig enough to have a suitable work area.

If the existing pipe is PVC you can simply cut the PVC and install a glue in type PVC trap. (A glue in trap is required because after you install the trap you will be backfilling the hole and slip joint type p-traps may not be installed in concealed locations.

[JWG]

Thanks. I do have the sewage ejector pump which pumps into my septic system. Digging out the hole will not cause voids under the concrete that will lead to problems will it? Thanks again for all your information.

[LazyPup]

After you dig out the hole and make your connection, you can back fill the hole with sand.

I would suggest wetting the sand a bit so it will compact, that way you will be able to compact it back into the sides under the existing concrete slab to avoid leaving too many voids. (it is nearly impossible to totally fill it without a small void but that is not a problem as long as you try to minimize how much void you have.

Continue compacting the sand in until the hole is backfilled even with the underside of the existing concrete slab, then cap it off with a couple 80lb bags of sacrete "Concrete Mix". The sacrete is a premixed concete with the correct proportions of portland cement, lime, sand and aggregate rock so all you need to do is add water to the proper consistancy and pour and finish. The Concrete mix is available at any hardware or home supply and is really cheap. Usually about $3 to $4 for an 80lb bag.