Due to the complexity and number of the fittings and
fixtures needed to install domestic systems, it is normal
for the plumber to quote this trade on a supply and
fix basis. However, many self builders will want to
supply their own sanitaryware and perhaps the boiler.
General
Key Points
1
Make sure that the ducting,
if not the water supply piping is set through the oversite.
If it is convenient to do so, a temporary tap can be put
on the end to act as a standpipe for the build until such
time as the proper stopcock is installed.
2
Ensure all plumbers dealing with gas piping or boiler
installation are CORGI registered.
3
The plumber should be on site as soon as the roof is
weathertight in order to notch out the top of the joists
and lay the carcassing pipework prior to the floor decking
going down.
4
Make sure that you order sanitaryware and kitchen units
in good time so as not to delay the trades.
Cold water is supplied directly into your home from the
mains via a stopcock positioned within the highway. The supply
must be at least 600mm below ground to avoid frost and it
is brought up within the house to the most convenient stopcock
position, usually below the kitchen or utility room sink.
The groundworker will
bring the drainage pipes up through the oversite. The plumber
then takes over and takes the soil and vent pipes up to connect
to the domestic waste water outlets. The plumber is also responsible,
in conjunction with the roofer for the vent pipes and skirting
through the roof and for any necessary leadwork to the roof,
liaising with the bricklayer for any pointing. The plumber
will usually be responsible for the installation of any gas
piping. Plumbers installing and commissioning gas fired systems
must be CORGI (Council for Registered Gas Installers) registered.
Plumbers installing and commissioning oil fired systems should
be OFTEC (Oil Firing Technical Association) registered. The
plumber is
usually responsible for the fitting of guttering and dowpipes,
once the facias are decorated, liasing with the roofers and
groundworkers.
The Roof
This has largely been covered in Build Stage 8 but as you
can see from the above list some of the items in First Fix
have to be done before the roof is on and others have to wait
until it is finished or even tiled. are to be carpeted or
exposed before ordering
so that they are made of the correct wood finish.
Vented and Sealed Heating Systems
Most of the older housing stock has a vented system, which
employs storage and header tanks in the roof that take up
any expansion as an overflow and top up and return water to
the system. Most new homes are now built with a sealed system
delivering hot water to the tap at mains water pressure. These
systems do away with the need for tanks in the loft and instead,
any expansion is taken by an expansion vessel connected to
a hot water cylinder that is capable of storing hot water
under mains pressure.
Hot Water Cylinders
Many homes have an indirect hot water cylinder where the
hot water within the primary system from the boiler passes
through a coil or heat exchanger within the tank, which in
turn heats up the main body of water. This 'secondary' water
is then drawn off to the tap. An alternative is the 'thermal
store'. Here the main
body of water within the cylinder is heated by the boiler
and cold water, passing through a coil, is heated up to provide
mains pressure hot water.