New plumbing system in house refurb - what to consider

[Billthebuildernot]

Hello,

My house is being completely renovated, including new plumbing throughout (1900s Edwardian terrace in South London)

Currently there is the old lead piping into the property which will be replaced.

The builder has asked whether I want a combi boiler only, or combi with a megaflo as well.

The house is a two storey terrace with a loft conversion creating a third floor, so will have

Ground floor kitchen + washing machine.
Ground floor understairs toilet
Ist Floor bathroom (Bath)
2nd Floor bathroom (shower)

Toilet/bathroom/bathroom are basically on top of each other, and kitchen area is fairly close at central point of house.

Heating will be by underfloor heating on ground level (and upstairs bathrooms) and radiators in bedrooms.

Renting in a nearly Maisonette with low pressure/flow (don't know what) - where landlord advised not to use washing machine at same time as shower or dishwasher, and the only shower dribbles when a tap is used/toilet is flushed, would like the best possible system in the new house!

I have a few questions/comments:

I can see people advise to check flow/pressure first. Given the property currently has small lead pipes coming into the property that will be replaced, is that relavent here, and will it tell me anything?

Do I need to wait until the lead pipe has been replaced to test the water pressure/flow in order to understand what is needed?

What is likely to be needed? - we would like not to be concerned whether dishwasher or washing machine is on when showering/bathing, and to be able to use a tap when in the shower, but accept that if using both showers we may have reduced flow/not enough water for the second shower (although it would be great if we could use both together!!)

Many thanks for any advice.

 

[hazetimesfive]

Don't use the builders plumber, get one that you can communicate with directly yourself.

 

[Billthebuildernot]

Thanks. That suggestion is not too easy to do however as the builder has given an 'all in price' and package. Hence the questions here so I would have some idea of things to raise with the builder/plumber.

 

[ALEC1]

DO NOT USE THE BUILDERS PLUMBER...

sorting it all out after wards is a depressing but lucrative job to the person who has to do it

Change builders if necessary...


Wise home owners employ their own plumber and heating engineer..

 

[Billthebuildernot]

No matter which plumber I use, do I not need to have a basic understanding of the questions I should be asking him?

i.e. can any plumber tell me what pressure/flow I have if I am going to change the lead piping or should this be done first?

 

[ALEC1]

at the end of the day its a judgement of character...

ask them if they live reasonably locally, are they registered with any particular manufacturer, are they passionate about their job.


you dont need to know about pressure and flow, but you do need to draught a set of expectations about the heating and plumbing performance.

do you want a hotch potch miss mash of manufacturers or one "branded" system that conforms to the design criteria of the boiler manufacturers.

Do you want a **** poor dribble as a shower or something you can reasonably expect in a 4 star hotel

do you want a system that lurches from off to on, or one that merely keeps the place at a programmed temperature with little variation...

those sort of things...

 

[Billthebuildernot]

thank you for the comments, but I am not in a position to appoint separate trademen for each and every part. I have appointed a building contractor who is undertaking the works. I am pretty sure that this is common scenario when undertaking a full house renovation.

I want to ensure that I have asked all the right questions/considered everything - I could leave them to it, but I want

As for trust, the builder has done 4 similar complete renovation for people that I know, and no one has had any problems with anything so I am not sure what else one can do. Equally all were different sizes and setups so I realise mine will not be the same as theirs.

So I am not sure of the instant negativity of the mention of any builder, all I was after was some help with the questions I have asked

 

[SimonH2]

You NEED to know the dynamic flow rates and pressures (and allow for it varying during the day) BEFORE you can settle on a suitable system. If this means you have to have the supply pipe replaced before you can measure what you'll actually get, then that's what you'll have to do.

One thing is certain, if you go for a combi (I wouldn't unless there was a very compelling reason), unvented cylinder, thermal store, or heat bank - if the dynamic flow/pressure is inadequate then you'll get disappointing results. So measure it first.

As to choice of system, there is no correct answer - only a "best tradeoff" for your situation and requirements. The fact that you have a loft conversion more or less rules out an open vented cylinder as you'd have no head - unless you added a shower pump (and negative head setup at that).

So that leaves you with the choice of a combi, unvented cylinder, thermal store, or heat bank (the latter two being different types of much the same thing). If your plumber "insists" that a combi is the right answer - then the right answer is a different plumber. Whatever the commercial arrangements, the advice already given stands about using the plumber the builder prefers rather than one who knows what he's doing. Ditto if he dismisses out of hand a thermal store or heat bank - even though it may well not be the right choice for you, that should be arrived at through a process of design, not prejudice.
The "best" answer for you will also vary with the type of water (hard or soft) you have - so what works in one place might not be best for a similar situation somewhere else.

EDIT: Just seen you're in London. From memory pressures can be quite low, so it's even more critical to get dynamic flow/pressure measurements.

 

[Weedrip]

I can see people advise to check flow/pressure first. Given the property currently has small lead pipes coming into the property that will be replaced, is that relevant here, and will it tell me anything?

Yes it help to understand the conditions available for the performance of your future system.

Do I need to wait until the lead pipe has been replaced to test the water pressure/flow in order to understand what is needed?

Again yes, this will define the conditions available. To test a pipework and then change the bore etc. will affect available parameters.

What is likely to be needed? - etc,

your on site installer is best placed to advise on this aspect, you also have someone to go to if it does not work, there are many aspects to consider in a plumbing system, a forum is probably not best placed to deal in to much detail.
One point I would wonder at though if the builder has given you a full all in price the spec and hence cost of just the plumbing / heating works could vary some considerable amount, take care you are not driven down in spec or up-charged for a system spec that should be being installed as std.

Good luck with your project

 

[indus]

at the end of the day its a judgement of character...

ask them if they live reasonably locally, are they registered with any particular manufacturer, are they passionate about their job.


you dont need to know about pressure and flow, but you do need to draught a set of expectations about the heating and plumbing performance.

do you want a hotch potch miss mash of manufacturers or one "branded" system that conforms to the design criteria of the boiler manufacturers.

Do you want a p**s poor dribble as a shower or something you can reasonably expect in a 4 star hotel

do you want a system that lurches from off to on, or one that merely keeps the place at a programmed temperature with little variation...

those sort of things...

Are you seriously suggesting the op ask a plumber 'are you passionate about your job?'

And who says you can't have different manufacturers in a good system?

Finally, what is this random theoretical four star hotel you are using as a benchmark???

 

[Billthebuildernot]

Many thanks for all the helpful replies. I have some reading to do and will then post some more questions tomorrow!!

 

[Dan Robinson]

Harsh but true there from Indus.

OP, not all builders plumber's are poor. But they mainly are. I do work regularly for a builder in Barnes and the fact that I'm independent is part of his/our sales pitch.

Once the customer has paid the warranties are transferred to the customer and the most the builder is afterwards is a messaging service.

Alec loves his integration and it does have its place.

You do need to know more about the key trades working on the property. Sparkies and plumbers are key trades who, if a problem arises afterwards, any remedial work will be hell.

my recent renovation I did the plumbing, but I made sure the sparkie and I were on good terms and communicated properly. What was done was a result of that relationship. Not the builder.