If you would like to install a separate shower unit without the need for doubling it up with the bath, there are several design considerations to make regarding its location and construction.
A complete shower unit may be purchased which includes all the necessary components. The shower, shower tray and walls of the cubicle are all pre-made and require only assembly and installation. Obviously, this set up is also relatively expensive.
Or, build in a cubicle making use of the walls of the room and/or additional stud walls constructed to suit. This method is more labour intensive but can represent a considerable cost saving. It also has the advantage that it may be built to suit your requirements more exactly.
The possibilities are quite varied. The shower may be built against one wall and stud walls constructed on one or two of the sides. The shower could make use of the corner walls of the room. There is also the option of building a shower as an integral part of a cupboard arrangement. The ‘open’ side or sides may then have a screen or curtain installed. Access to the shower may be from one side or the corner of two sides.
Shower unit plumbing
Consideration at the design stage should also be given to the plumbing. It always looks far neater and professional if all the pipework is hidden from view. This can be achieved either by routing the pipes through the rear wall of the shower if this is possible, or by building a false wall in front of all the pipework.
Shower unit drainage and waste
Drainage from the shower tray can be a little problematical as the need for a ‘fall’ in the waste pipe can be difficult to achieve. The fact that the base of the shower is at floor level means that the waste will need to drop below it. If the joists supporting the floor run in the same direction as the waste pipe, there may be room to fit the waste within the floor depth. However, you’ve probably just discovered that yours run the other way. The way round this is to raise the base of the shower to provide the necessary slope of 6mm per 300mm length of waste pipe. A quick calculation will show you that the additional height of the base will not present too much of a problem. (a 3m run of waste will require the base to be lifted by 60mm). Some of the "top of the range" shower trays come with an adjustable base height.
The tray is fitted with a shallow trap to minimise the under tray space requirements, but not if the waste is connected directly to the main stack via a strap boss. In this case it is required to be a deep trap.
Shower cubicle walls
Stud walls may be constructed to suit your design. The face of the walls should be made of marine grade plywood since the area will be subjected to considerable moisture. This is screwed and glued to a frame of suitably spaced and strengthened timber studwork.
Remember to seal all the angles between walls and the edges of the shower tray with mastic, so that there is no possibility of water percolating through.
The false wall referred to earlier is built on the same principles. It will accommodate the pipework between the timber uprights and also provide support for fixing the shower controls and adjustable rail for the shower head.
The surface of these walls should be sealed and may then be clad with ceramic tiles using a waterproof adhesive.