Replacing the kitchen sink

Modernising an old kitchen starts at the sink, and it’s not difficult. Replacing a sink with one of the same kind is
straightforward; replacing an old fireclay sink with a new enamel or stainless steel unit is more complicated
but not beyond the skill of a DIY amateur householder.

Turning off the water supply

The cold water supply to your sink will be direct from the main; turn it off with the stop tap in the house (sometimes
below the sink) or by a stop tap outside, usually in or near the path. Hot water should be controlled by a valve in the pipe from the cold tank in the roof to the hot cylinder. If your house or flat hasn’t such a valve (many haven’t) having turned off the cold stop tap simply turn on all hot taps until no more hot water comes out.

Switch off immersion heater and turn down boiler to stop water in the hot cylinder overheating, but there’s no risk of
damage because while the 25 or 50-gallon cold tank will empty, the hot water cylinder itself remains full. (If you can’t bear the thought of wasting all that hot water, turn off heating the night before.) If hot water is supplied by a separate gas or electric heater, turn off the valves on the heater itself.

Removing the old kitchen sink

Begin by disconnecting the waste from the old sink: this will be fastened either by a bolt running down through the
centre of the waste fitting, or by a large nut beneath the sink tightened on to the threaded stem of the waste fitting. You may have to tap the waste fitting to break the seal of old hard putty which will hold it to the sink. Then slide the sink forward off its supports (take care: it’s heavier than you think). If you are replacing it with a similar fireclay sink, simply clean off beneath the tiles where the old sink fitted and slide the new one into place.

Grout joint between new sink and tiles carefully – it’s a dirt trap. Reconnect the waste with fresh putty. If you want
a modern sink in its place, there’s rather more to do. If pipes to taps over sink are sunk in wall, hack off tiles to reach them. (Keep a piece as a sample if you want to match them.) Dismantle any cupboards under sink; take away any wooden sink supports.

Waste fittings are held by a bolt through the middle which unscrews (left) or by a nut beneath. When undoing nut, take
care to avoid damaging the trap; lead fittings are not very strong.

In changing an old-fashioned sink for a modern one you’ll have to remove some tiles to get at pipes behind taps above sink. To avoid breaking more tiles than necessary, cut the grout between them with razor blade. Wooden sink supports are easily removed : saw through tubular supports, cut out or break cast-iron ones.

Cut tubular sink supports .Cast-iron ones built into the wall, can be cut out with a cold chisel; or you may be able to break them off by a blow with a heavy hammer – cast iron is brittle. Set the new sink temporarily into its cupboard
unit and stand that against the wall, marking where sink top, bottom of tap stems and waste will come. Move it out again and cut a groove in the wall so back edge of sink fits snug behind line of tiles.

Fitting the new taps and the waste outlet

Some sinks and taps will be supplied complete with fitting instructions; if yours hasn’t such instructions this is what to do. Fit the taps in place, each one with a thin nylon washer on top of the sink (this makes the tap-to-sink joint watertight and, with enamel sinks, protects the enamel from the metal of the tap). Underneath thesinkcomes
a thick, shaped nylon spacer washer with the flat side against the underside of the sink. On to that goes the backnut, with its flat side against the washer. If you are installing a mixer valve instead of individual taps, there will be the same thick washers underneath, but one large sealing gasket on top of the sink instead of the thin nylon washer for each tap. Tighten the backnuts.There are different kinds of waste fittings. Fit the nylon or rubber washer supplied,inside the sink beneath the chrome outlet and another outside (beneath) the sink above the nut which tightens the fitting.

If the sink has no overflow the waste will be a plain threaded one, it must have a slotted waste, similar to the plain waste, but with slots cut in the waste just below sink level to let in water from the overflow. This overflow
may be built in as an integral part of the sink, but in a modern unit it is most likely to have a flexible plastic pipe which runs from the overflow fitting (like a miniature waste) to a collar which fits round the slotted part of the waste. This kind of waste unit will have immediately below the sink above the overflow unit, and one below the overflow unit between it and the nut which tightens the whole assembly together. (Metal-window putty is an alternative
to nylon or rubber washers for sealing metal fittings, but putty should never be used with plastic fittings.)

Tighten the waste assembly. Now fit the sink unit to its base: small angle brackets screw into the framework and hold the turned-up lip of the sink top down to the base. More information about plumbing can be fond here. London Plumbers