low-pressure showered

[ForeverbyJudyBlume]

We' (well a builder but with some input from dh and I) have been renovating an attic en-suite and the pressure in the shower (same position as before) is awful. It was never good but is now worse. After a lot of fiddling with the boiler and the hot/cold ration we've made it tolerable but having a shower isn't exactly joyous. The only problem that I can see is the room is just too high up for water to flow properly. We'd bought a beautiful Dornbracht head which we've tragically concluded is too big, so swapped that for a smaller one, which makes things mildly better but still not great.

Does anyone know anything about low-pressure showerheads or is able to recommend one? As far as I can see they are mainly used for water-saving rather than for producing a decent-pressure shower but if anyone knows otherwise I'll be grateful ....

do you have a combi boiler or a cylinder?

what colour?

how old is the house?

A white combi

the house is old - circa 1880s

I think you’re likely to need either a pump or some sort of pressurised system to properly correct it. We’ve just had to do the same to make our upstairs shower tolerable. We’ve put a thermal store in but what you use depends on what boiler you have (we have a conventional oil boiler and an aga for our heating/hot water). It was £££ but mains pressure hot water throughout is so worth it.

You need good pressure and also flow for a good shower. They are not the same thing.

An 1880s house may have had a replacement water supply pipe, but there may be lead, iron and copper pipes. What's the flow and pressure like at the kitchen cold tap? What's it like at the upstairs washbasin? It is noticeably worse at the hot than the cold? A plumber can measure flow and pressure at several points to try to work out the cause of the problem, and what can be done to improve it.

as you have a combi, the static pressure should be that supplied by the water main, minus about 1bar from the increase in height, and some losses due to resistance in the boiler and in the pipework, when water is flowing. As a rule of thumb, if you put your thumb over the spout of a tap, you should be unable to stop the water coming out. This is pressure.

If the pressure is a lot better at the ground floor, it may be that you can get an improvement by running larger, straighter pipes to and from the boiler, but it may be that the incoming supply to the house is poor.

If you fill a bucket at a tap, time it, and calculate litres per minute delivered, this is measuring the flow. 10 lpm gives a reasonable shower.

Look for any sign of small pipes (especially flexibles) supplying the shower, and any ball-type service valves. These both obstruct water flow and can be changed for larger which may help.

Thanks so much both, It's a four storey house with 2 boilers, so we don't have to heat upstairs floors during the day (dh and i both work from home). There's no problem with water pressure on other floors, But it sounds as if this isn't so much to do with the boiler as the pipework and perhaps unsuitable piping to the upstairs shower. Would it be easier to install a pump than redo all the pipework? I'm not sure our builder is qualified for either, assuming this is a proper plumber's job? Thanks again

Yes, you need a plumber.

I'd prefer to start with adequacy of the pipework and supply. If you put a shower pump upstairs it may be sucking from the pipes and prevent other taps from running (or may suck air from them).

If you have a modern house with a plumbing duct in the corner of kitchen and bathroom it may be straightforward to poke a new pipe down it. Flexible plastic pipes are available.

Modern combis and unvented cylinders need a good flow to give of their best.

Thank you very much. There is no problem with the pressure in the basin in the bathroom, we’re going to do your bucket test and work on it from there. It doesn’t sound anyway as if an aerated showerhead is the answer