Several options exist for selecting a shower drain to use for the installation of your pre-constructed shower base. This selection is largely dependent on your shower pan as well as your particular situation.
Also, your home’s piping and manufacturer’s reference for both the drain and shower pan may help guide your decision on the best drain assembly.
Note that shower drain assemblies are normally designed for a two inch drainpipe, and not the one and half inch pipe typically seen on tub drains.
Two inch pipes are recommended for showers because of the low flooding threshold and it helps drain the water much quicker than a one and half inch pipe.
Therefore, if you’re changing your tub-shower arrangement to a shower, you may need to change the size of the drain pipe as well.
Each drain assembly type has its own method of installation. You’ll need the following tools/equipment:
- Channel-lock pliers
- Tubing cutter or hacksaw
- Caulk gun
- Silicone caulk
- Shower drain assembly
- Plastic pipe solvent glue (if required)
- Plastic pipe primer (if required)
Solvent-Glued Shower Drain Installation
Drain assemblies of solvent glue are only recommended when there’s access beneath the shower from an incomplete crawlspace or basement.
If this access isn’t available, then a better option would be that of compression style.
These type of shower drain assemblies are typically ABS plastic, although older kinds may be made from PVC.
If your drainpipe is plastic, ensure the material matches that of the drain material.
Similar to a compression-type shower drain, this can be used with shower bases of fibreglass, acrylic, and steel.
Getting the right pipe measurement may be harder with solvent-glue fittings, so try to measure with care and ensure the pieces are test-fitted before applying glue.
Adjust the Drainpipe
Adhere to the manufacturer’s guide for setting the drainpipe to the right height.
For majority of drain fittings, this requires trimming the pipe at the precise subfloor level.
Ready the Drain Assembly
Solvent-glued shower drain assemblies mostly come in various parts:
- An upper part extending down the shower base drain opening
- A strainer cover
- The lower part with female threads attached to the upper part
Start by disassembling all the drain assembly parts and carefully reserving any rubber or cardboard friction washers.
Insert the Drain Assembly’s Upper Part
Put a bead of silicone caulk round the shower drain opening flange.
Set the upper part of the drain assembly immediately in the drain opening and hold down.
Secure the Drain Assembly
From underneath the shower base, position the rubber sealing gasket, and then the paper friction gasket, on top of the upper part’s male threads.
Thread the drain assembly’s lower part to the upper part.
Screw the drain assembly pieces tightly until silicone oozes out from around the drain opening flange.
Clean off any surplus silicone. Have the metal grate attached to the drain assembly top.
Solvent-Glue the Drainpipe to the Drain Assembly
From underneath the shower base, smear plastic pipe primer on the drainpipe external edge and the internal surface of the fine socket on the drain’s lower part.
Also lightly smear solvent glue on these surfaces.
Slide the drainpipe in the socket on the drain part immediately and hold still until it bonds properly.
Allow the silicone caulk and solvent glue to cure for 24 hours prior to making use of the shower.
Tile Shower Drain Installation
Custom-tiled showers have drain assembly units of three pieces, of which each is installed at various phases of the installation of the tile pan.
The shower’s waterproof membrane liner is positioned in the middle of two lower flanges bolted together.
This liner serves as the lowest water resisting later and will ensure whatever gets in under mortar still goes down the drain rather than leak from the shower pan.
The strainer cover, the final piece, is the only visible piece after the shower pan is completely installed.
If your custom shower base is being installed by a tile expert, then drain installation will be handled as part of their task.
Fix the Bottom Flange
After preparing and cleaning the shower subfloor, the bottom flange of the shower drainpipe should be installed, usually using solvent glue.
When this is done, a mortar bed is troweled round the drain opening which creates a slope of a quarter inch per foot towards the drain from the walls.
After the mortar bed dries, a waterproof membrane liner is fitted on the floor and the shower drain lower flange.
Seal the drain flange and the liner using silicone caulk, and then trim the liner about the drain opening.
Fix the Middle Flange
Place the drain fitting’s middle flange over the drain opening and liner, securing it to the bottom flange underneath the liner using bolts.
The liner will be positioned tightly in the middle of the flanges.
It’s common practice at this point to pour water on the shower pan so as to check for leaks from the liner.
Shower Drain Installation: Fix the Strainer Assembly
Attach the drain and strainer assembly so it goes above the liner.
There are usually male threads in this piece which screw down to the middle flange female threads.
The extent of extension of the strainer assembly is subject to the tile installation – follow the manufacturer’s guide.
It gets up to one and half inches if the tile is laid on a solid bed of mortar.
You’re now ready to install the rest of the ceramic tile.
This typically involves another layer of mortar before applying the ceramic tile over it.
Before using the shower, ensure the tile is grouted, sealed and cured.