How to install a shower in your home

Taking a shower is the ideal way to freshen up, much more convenient than having a bath and considerably cheaper. Among the other benefits of a shower are its constant running temperature, and the possibility of fitting it away from the bathroom to avoid early-morning congestion.

You have the choice of converting existing room space to form an enclosure , or of buying one of the many prefabricated enclosures now on the market—many of which come complete with fixtures and fittings.

If you plan to make your own enclosure, base the design of this on the use of a prefabricated shower base. This considerably simplifies the all-important drainage arrangements, which are often the greatest problem where the bath is not used. From a safety point of view, make sure you provide adequate lighting and room for movement.

On the plumbing side, hot and cold water supply pipes have to be laid on as well as drainage, and these points go a long way towards influencing your choice of site. At the shower, the hot and cold water can be mixed by independent taps or by a single control. Supply pipework and the shower head connection can be concealed beneath tiling, perhaps behind a false panel fixed to the wall.

Another alternative is to provide a shower over a bath, either by fitting combination bath/shower mixer taps which can be readily bought, or by laying on piping for an independent shower. With this arrangement, you have no shower base or drainage to worry about.

If it is difficult or impossible to lay on a suitable hot water supply, then an electric ‘instantaneous’ shower or gas heater may provide the answer, although both have disadvantages compared to a properly fitted shower. The instantaneous electric shower has a poor flow rate, and the gas shower needs ducting to the outside.

The water supply

For proper operation of a shower, there must be sufficient water pressure at the shower rose. In many British houses, the water pressure at most taps is provided by a cold water storage cistern, mounted above the level of the water outlets. The higher the cistern above the outlet, the greater the pressure will be; the vertical distance measured from the bottom of the cistern to the outlet is called the head. For a shower, the head is measured to the rose and ideally should not be less than 1.5m, though in simple plumbing systems a head of 1m may be sufficient.

If the head is between about 1m and 1.5m, then an adequate shower may be achieved if you can keep connecting pipework runs short, and with very few bends.

For heads of less than a metre, or where it is not possible to have short simple pipe runs, there are three main solutions. The first is to install a flow booster—a type of electrical pump which increases the pressure. Operation is automatic.

The second solution is to increase the height of the cold water storage cistern by raising it up on a sturdy wooden platform. But there may not be room in your loft to do this. Another solution is to use an instantaneous shower connected directly to the cold water mains.

In some areas of the UK, houses do not have cold water storage cisterns; instead, all cold taps and so on are supplied direct from the mains. Hot taps are usually supplied from a conventional hot water cylinder fed from its own small cistern. This particular method of obtaining water is what is known as a direct system. With this arrangement it is not possible to fit a conventional mixer type shower: it would contravene water regulations. You can either fit an instantaneous shower or perhaps modify your plumbing so that the shower is fed from a suitable, conventional cold water storage cistern.

In Canada, the whole water system, including the hot supply, is fed direct from the mains, and showers designed to work with this system are readily available. In Britain, a fully direct system like this will almost certainly use a ‘multipoint’ type gas heater: you should consult both your gas board and your water authority about the possible problems of connecting a shower to such a supply.

Temperature fluctuations

Water starvation in either hot or cold supply pipes can cause temperature fluctuations in the shower, which could be annoying or even dangerous. It is very sensible to buy a shower that is thermostatically controlled, or at least has a temperature limiting device so that the water never gets dangerously hot.

For showers in an indirect plumbing system, it is a good idea to use separate hot and cold supply pipes that do not feed any other fittings—then turning on any other taps in the home will have no effect on the flow.

In the UK, alterations to existing plumbing installations are strictly controlled by local water authority by-laws. Because of this, you should inform your local water board of your plans at least seven days before work starts. As well as giving practical advice, they will warn you against any possible infringement of their regulations.

In Canada, you should check local building ordinances to make sure that the work you are undertaking complies with them.

Drainage considerations

Although deciding how to supply water to a shower can be tricky, it is usually possible to get over the problems one way or another. Leading the dirty water away, though, to a soil stack or waste water drain often presents far more constraints. PVC piping, being easy to work with, is the logical choice for this sort of job. But breaking through walling, both internal and external, is usually necessary if the discharge pipe is to remain completely hidden from view. And unlike hot and cold supply piping, the discharge branch cannot be taken under the floorboards unless the run is between, and almost parallel to, the joists underneath.

Your choice of site for the shower must therefore take into consideration drainage arrangements almost to the exclusion of everything else.

Following the recognized and approved guidelines on drainage, the branch discharge pipe length is limited to a length of 3 metres and to a slope of between 1° and 5°.

An ‘S’ trap can be employed if a pipe drop is required , such as when underfioor drainage is possible, but otherwise a ‘P’ trap is preferable. Use pipe of 42mm diameter.

If the shower base discharge pipe can be arranged to go directly through the wall and connection has to be made to an outside soil stack or waste hopper, much of the fall can be arranged externally.

Use professional help if you have to break into a cast-iron stack, though it is usually easier to replace the whole stack with the PVC equivalent so that the shower and any future additions to the system involve the minimum amount of work.

Installing a shower base

The first stage of the job is to prepare structural work’—such as a timber frame for the enclosure—if this is necessary. Thereafter the sequence is:

Run hot and cold water supply pipes to the point where a connection is made with the shower controller.

Follow carefully any recommendations made by the shower manufacturer as to where to break in to the supply. Use 15mm copper piping and T’ connections to connect with your existing hot and cold water pipes, keeping bends to a minimum and pipe runs as short as possible. Use either compression or capillary fittings—the latter are cheaper, and neater looking. The skilled techniques of joining and bending copper pipes should not be attempted without prior experience.

Remove the shower base and its accessories from the protective wrapping, taking care not to scratch or damage these parts. Lay fixing accessories on the floor close at hand —but not in the immediate working area—in a logical order ready for use.

Lay the shower base on a protective groundsheet, and locate the tubular legs in the sockets welded on each side of the steel shower support frame. Fix the frame to the wooden shower support, which may be flooring grade chipboard or similar.

Secure each leg to its socket upstand using self-tapping screws.

Assemble the adjustable feet but hand tighten only as later adjustment is necessary. Place the shower base on its feet.

Fix the waste outlet to the shower base, incorporating the sealing washers provided and using a waterproof mastic to complete the seal. Use a holding spanner while tightening the larger nut with an adjustable spanner. Attach a short length of pipe to the trap and temporarily secure the trap to the waste outlet, then mark on the wall the exit position of the pipe.

Cut a hole through the wall for the discharge pipe at this point. You will find it easier to remove a small section of skirting first if this is in the way.

Reposition the shower base, then using a bradawl, mark the floor fixing points of its supporting board.

Check the level of the shower base, ensuring that the trap has sufficient ground clearance, and tighten the fixing nut on each leg.

On solid floors it is difficult to drill and plug for eight screws and still have perfect alignment—especially as the holes have to be angled so that the shower base does not impede the actual screwing process. It is easier to fix the support board on its own to the floor, attaching the feet later.

Temporarily link together the trap with a short length of pipe, arranged to protrude through the wall near to where it is to discharge into a hopper or stack. If you have the choice, direct the pipe to a hopper rather than attempt entry into a stack.

If discharge is made to a soil stack, mark a point on the stack which is level with the protruding pipe and another point a little below this so that a drop of between 18 and 90mm per metre is obtained for satisfactory discharge.

Assemble a replacement triple socket, boss branch and pipe socket and then gauge the length of the piping which has to be removed from the stack in order to fit these. Transfer the measurement to the stack in such a way as to embrace points ‘A’ and ‘B’ , with the pipe socket coinciding with the latter.

Cut out the stack length with a fine-toothed saw, taking precautions or using assistance to keep the upper and lower lengths in position afterwards.

Dismantle the triple socket from the boss branch and pipe socket. Push the triple socket into the top part of the stack as far as it will go. Then fix the boss branch and pipe branch on to the lower part of the stack. Complete the fitting by pushing the triple socket down into its final position.

Insert the spigot bend into the boss branch, attach brackets to the outside connecting length of the discharge pipe and fit this into the spigot bend Twist the boss branch until the supporting brackets on the discharge pipe make contact with the wall.

The discharge pipe from the inside of the house should by now meet the discharge pipe attached to the stack, and the two can be marked for cutting so that you can fit a 45 bend where the inner pipe leaves the wall. Remove both pipes and cut these to final length.

Replace all pipes, the longer one with its fixing brackets in place. The shorter length is fixed first to the trap and then to the bend. Screw the trap to the waste outlet of the shower base. It is essential that all pipes and fittings are perfectly aligned and that no force is used to keep them in place. Make minor adjustments if necessary.

Mark and fix supporting brackets, normally required only for the outside length. Make alignment marks at each of the fittings.

Dismantle pipework and fittings that require solvent welded joints, prepare the joints and reassemble as before.

If the discharge pipe is to be led to an outside hopper, cut the protruding pipe length to fit a slow bend. Attach this to whatever length of pipe is necessary to complete the run at a convenient point above the hopper, and provide support brackets.

Make good the hole through the wall using a proprietary filler paste. There are now aerosol foam sprays on the market which ai-e waterproof, allow for expansion or contraction, and are easier to work with than the more traditional compounds.

Test the pipework, first for stability and then for watertightness, using a pail of water until connection is made with the supply system.

Connection of the hot and cold water supply pipes to the shower controller is made in the course of assembling the shower enclosure, and the procedures should follow exactly those stipulated by the manufacturer. The valve and spray piping are attached to a mounting panel attached to the wall or set into the wall along with piping. With self-contained shower enclosures, the mounting panel is attached to the rear of the cubicle with a waterproof gasket arrangement.

Completing the enclosure

Once the shower base installation is complete, you can attend to the completion of the shower enclosure. This is a relatively simple job if you are using a prefabricated kit, which often requires little more than a few minutes with a screwdriver. Built-in enclosures requiring woodwork, tiling and other jobs take much longer to make but can be matched completely to the design of the room.

Install an electric shower

An instant electric shower is an attractive proposition if use cannot be made of conventional hot and cold water supplies. In most instances, connection of the heater is direct to the mains water supply—so a shower of this type is especially useful if a hot water cylinder is not incorporated within the system. Pressure and flow variations within the system may have a marked effect on temperature stability, however. The heater needs direct and permanent connection to the electricity supply through a double-pole linked switch. The appliance must be earthed, and protected by a 30amp fuse. For additional safety, site the heater well away from the direct spray at the shower, and locate the switch outside the bathroom.

You can interrupt the rising main at any convenient point. Remember to keep the pipe run as short and as straight as possible. This Deltaflow unit requires a cold water supply which has a minimum static pressure of one bar which should be available from most mains supplies. In most houses, though, you cannot use a cistern-fed supply because the head will not be great enough.

If in any doubt, seek professional help. In some parts of Canada, you may need to have the electrical work done for you.

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