Routing water pipes via loft

[Jamie2106]

Hi all

I'm planning an ensuite and as the existing bathroom is in the next room, I was planning to run the hot and cold pipes up inside the wall and through the loft above the ensuite.

I can then put t-joints in along the horizontal pipes in the loft, and drop down vertically at the appropriate points to feed the wc, basin and electric shower.

Other than ensuring the pipes are protected against freezing, would there be any issues with this?

There is a combi boiler on the same floor as the bathrooms, so I'm assuming it will be capable of pumping water up to the loft, as it is only the same as it having to pump water upstairs if it was downstairs in say, the kitchen. Cold water should be able to get up there as there would have been a tank in the loft at some point.

Doing it this way has one very big advantage in that I can do it myself with plastic, all joints in the loft would be accessible, but I would use copper for the vertical drops, with the ends bent using a pipe bender to exit the walls, so there would be no inaccessible joints in the wall.

Do I need to consider anything else?

thanks in advance

Jamie

 

[terryplumb]

Sounds OK to me ,but why an electric shower ? Combi will give you a better flow .and if you already have one electric shower you will need to ensure the installation / supply can cope with the demand of two

 

[Jamie2106]

Hadn't thought about a mixer shower, my understanding was an electric shower would be less likely to change temperature if someone elsewhere in the house flushes a loo or whatever. I have already run a 10mm cable for the second shower, to be connected (by a qualified spark) to a separate MCB on the consumer unit. Do I need to take into consideration anything in terms of the water supply to the two showers?

 

[terryplumb]

Has your qualified spark agreed to you running cable ? As he will be taking responsibility for the design ,installation methods etc ,etc ? Has he established that your electric installation has the overall capacity to be able to support two powerful electric showers ? As electric showers take mains pressure cold water ,they can be starved when other water outlets are running ,but this depends on your mains cold pressure. A thermostatic mixer plumbed into your combi will adjust the cold / hot water mix to stabilise the temperature at shower head. Having said that a lot of combi boilers will struggle to supply two mixers simultaneously ,again cold mains water pressure and the kW output of the boiler are very important to take into consideration.

 

[Jamie2106]

Yes he has agreed to me running the cable, as in literally just running it up the house and through the loft to be connected by him, no different surely to him employing a lad to do the donkey work? He also installed the consumer unit so I assume he knows it's limitations.
The boiler is at the smaller end of the scale for the size of house, a replacement is planned but not for a while, I will look into perhaps an electric in one bathroom and a mixer in the other

 

[terryplumb]

Not a bad compromise jamie. And wise to have consulted the spark before doing anything. If you do decide on a thermostatic mixer as well as cold mains supply to it you just need a hot supply as well ,to answer your earlier question. ( and no electric cable )!!!

 

[Jamie2106]

Thanks Terry, appreciated

 

[Doggit]

I assume you can't lift the floorboards in the bathroom, as most of the pipes you want will be under the floor, and then take them through to the en-suite bathroom. If you aren't likely to have both showers running at the same time, then the current combi will be fine until you upgrade. Unless you've got a very good incoming water mains pressure, then you'll get a pressure drop in the showers whether they are electric or off the combi if someone flushes a toilet, or turns on a tap.

 

[John D v2.0]

Being honest I'd go for the Combi option as gas is much cheaper than electric, but mainly because the most powerful electric shower is about 11kw, whereas your boiler will be over 20kw.
Yes, you won't be able to run both showers at once and get a decent shower unless you have a 30kw plus Combi*, but a bit of coordination and it'll still be way better than electric.
*I looked into copper downpipes that recover the heat from the shower drain water, and although you'd easily get two showers out of a 24kw Combi with one of those, the part costs over 500 quid to buy and is nearly 2m long! But might be a more viable option than changing a perfectly good boiler and will pay for itself in gas in, say 5-10 years.

 

[FiremanT]

Jamie

There is a combi boiler on the same floor as the bathrooms,

Jamie,
The obvious problem with using a combi for a shower is that in the event of (a real risk) you will have no hot washing facilities. A shower off ANY combi is always leagues ahead of ANY electric one. Where practical, I would always suggest the most often used shower is via the combi, with an electric in the other, ensuring a back up.