Advice re complete refurbishment wanted

[farfrae]

Newbie alert; so please be gentle with me.

I live in a detached house in south Wales near Carmarthen and am looking to build two small extensions and undertake a full internal remodelling of my house.

Had a meeting with the architect yesterday and the prices from the QS for the whole job are astronomic (i mean seriously). So I'm thinking about using a main contractor to build the extensions and do the structural work and then perhaps use individual trades to finish the work myself.

So how would you advise that I

a) design the system? The house is single storey (but with two substantial changes in floor level) and fairly well insulated. 150 square metres including the new extensions. We want to install underfloor heating throughout (there is sufficient existing floor depth to add 50mm floor insulation, wet UFH and screed). An oil fired boiler (we are deep in the country) and solar HW. Two bathrooms will need towel rails, one will be wet room. What's the best way of integrating an oil boiler and solar HW? Not being in the trade how do I know which is the best boiler, pipework, fittings and which are cheap and cr*p when companies are giving me quotes (i.e how do i know I am comparing like for like?).

b) go about find good local plumbers with experience of this type of system (oil, UFH and solar). Is it better to keep this all with one firm or use a UFH specialist for that part?

All advice about what to look out for gratefully received as I think you guys will have far more sensible advice than my architect who can draw good plans but I doubt has any practical knowledge! Thanks in anticipation.

 

[AWheating]

Best to keep it within one plumbing firm unless the cost saving is good to avoid conflicts

A three coil unvented cylinder would be a good call for your hot water demands but its hard to give certain advise without more information. What is the pressure and flow rate of your cold water supply? for example.

Get a min of three quotes, come back here and ask about what they are purposing and we can advise on boilers etc...

 

[farfrae]

Best to keep it within one plumbing firm unless the cost saving is good to avoid conflicts

A three coil unvented cylinder would be a good call for your hot water demands but its hard to give certain advise without more information. What is the pressure and flow rate of your cold water supply? for example.
..

many thanks. Water supply is a private supply from a spring to holding tanks. There is then a pump and pressure vessel. Pump is to be replaced as currently has a damaged impeller and should be around 3 bar (or more if required). Not sure of flow rate at present.

 

[dontknowitall]

You don't say how large your extension is but a guide price is £450 to £650 per square metre. Using an architect is like using an accountant - they do add to the price but can save you much time and money during the build (much as the accountant can save you paying too much tax.)

If it's a 50m2 extension then the bill could easily look like £25,000.

If this is of any help of course!!