A over bath shower is the only way to go if you have a small family bathroom and you need to fit in a tub and a shower. There are problems and compromises involved, however.
The different parts of an over bath tub shower that you need to think about are:
- The tub itself
- The shower screen
- The shower head/unit
Over Bath Shower Tub Options
Your choice of bathtub will be limited because you need one that has a reinforced base. The stronger base is designed to withstand the weight of an adult standing at one end of the tub while using the shower. This puts a lot of stress on an ordinary tub, it bends and cracks.
Choose a design that has edges that slope down towards the tub, rather than towards the wall. You need the water from the shower to all drain into the bathtub. If your bathtub has even a small "rollover" sloping towards the wall then water will collect and it will cause problems when the water starts leaking through the grout and sealant.
One Piece Tub Shower Screen Options
You will need a shower screen to prevent splashing water all over your bathroom.
This is the lowest cost option and the easiest to install. All you need to do is to fit a shower curtain rail to the ceiling or wall and choose a shower curtain.
A curtain will stop the water splashing everywhere, but the end of the curtain needs to hang inside the tub. If it hangs outside it will just divert the splashes in a stream to the bathroom floor.
Feeling a cold shower curtain against your back while in the shower can be unpleasant. Cleaning it is as easy as spraying it with anti-mold spray every few days and putting it in the washer to remove any stains.
Fixed Shower Screen
This is the best solution. With a fixed shower screen there will be sealant along the edges where it meets the wall and bathtub. No water should leak out. If the shower screen is knocked however, the sealant will crack and you will find water where it should not be. Stains will show up badly, especially if it is a glass shower screen and it will need frequent cleaning.
Folding Shower Screen
A folding shower screen sounds great, but there are problems. There will be sealant between the shower screen and the wall, but none where the shower screen meets the bath. The bottom of the opened out shower screen must hang over the bath, or you will have floods of water on the floor.
Over Bath Shower Options
Your shower can operate via a bathtub faucet shower diverter or from a separate pumped shower heater unit.
Bathtub Faucet Shower Diverter
You will need to install a new bathtub faucet that has a shower diverter, unless you already have one. This has a lever that you push or pull to divert the flow of water from the tub to a shower head. The shower head can be a hand held one, like one you would use to wash your hair, or it can be fixed to the wall.
Children and disabled adults will find a hand held shower head very difficult to use, so in this case, fix it to a shower riser rail on the wall.
The water temperature of the shower is varied by adjusting the hot and cold water flow at the bathtub faucet, so every user will need to reset the temperature every time.
You might have a problem with low water pressure, depending on your water system. Many houses have a hot water tank that has a built in cold water header tank, rather than being filled from a header tank in the loft or roof space. Your shower head will have to be fixed below your header tank, or water will not come out of it.
There may also be problems with water flow if someone turns on a tap or flushes a toilet elsewhere in the house. The cold water flow at the bathtub diverter faucet will diminish and you could be scalded as the water suddenly gets too hot. Conversely, if someone runs hot water in the kitchen the cold water flow at the bathtub faucet will be reduced and your hot shower will turn into a cold one.
Separate Shower Heater Unit
There are two types of separate shower heater units, pumped and unpumped. The type with a pump runs from your loft space header tank, low pressure cold water supply. Shower units without a pump run directly from your high pressure mains cold water supply.
Mains Pressure Shower Units
These are cheaper because they have no pump, but there are problems. If someone turns on another faucet connected to the mains water supply, then the supply to the shower unit falls and the temperature of the shower output increases to uncomfortable levels, instantly. Do not buy one of these if you have children.
Header Tank, Pumped Shower Units
A separate, pumped shower unit is the best solution. It draws cold water from your header tank and raises the shower pressure by using a pump. The pump is noisy, but you can put up with that. Water supply does not fluctuate, so your shower stays comfortably hot.
The temperature setting remains the same unless someone alters it, making it easy for children and intellectually disabled adults to use.
Buy a shower unit with as powerful a heater as possible. The temperature of the water is governed by the water flow. For a cool shower the water flow is higher, so it is heated less. If you want a hot shower with a good flow rate then you need a powerful heater that will still heat the water, even when the flow rate is high.
A smaller heater will mean that the water flow rate has to be decreased in order to heat it to the desired temperature.