Placement and fit of sinks and faucets are critical

Sinks (and faucets) are often the most-used areas of a
countertop. They define a prime function of a countertop and are often are a
major visual feature. As such, the placement of the sink hole (and the sink
itself) and the faucets are critical, not only to meet the necessary
functionality but also to ensure the client’s aesthetic demands are met.

At the very basic level the sink and faucet (which includes
other fixtures like soap dispensers and sprayers) must not interfere with each
other, and all must fit within the space defined by the cabinet, the wall,
backsplash, etc. Sinks have to fit, faucets need to reach the sink, and soap
dispensers shouldn’t drip on the countertop.

Most sinks are undermounted, although integral and drop-in
are used too. The sink itself takes up most of the space within the cabinet,
and it’s vital that the entire sink fit inside the cabinet with a little room
to spare. Once cast it’s impossible to move a hole (or an integral sink), so
getting this right is critical. Remaking a countertop because of an incorrectly
positioned sink is a very costly mistake.

An undermount sink is centered on the hole in the
countertop, so that hole must be positioned correctly. Sink flanges shouldn’t overlap
the cabinet frame, and generally the sink is located towards the front of the
cabinet so as to leave as much room as possible for the faucet and other

If the sink is positioned correctly, there won’t be
interference with the cabinet when the sink and countertop are installed.
Special attention is needed when a sink is located in front of a window.
Windowsills can interfere with tall faucets, since the faucet could extend
above the top of the windowsill. It’s important to ensure the sink and faucet
don’t interfere with the cabinets or the windowsill. This is also true for
raised bartops that are behind sinks with tall faucets.

Sink and Faucet

                                                    Typical layout for an
undermount sink and multiple plumbing fixtures.



                                                                   Tight fit for a tall
faucet in front of a windowsill.

Sinks are positioned first, then the plumbing fixtures come
next. Plumbing fixtures need to be mounted near the sink. This places them
closer to the sink and farther from the wall. Not only does this look better
aesthetically, it ensures there will be space behind the faucet and in front of
the backsplash. No matter how beautiful a countertop is, no client will be
happy if the faucet is located in the wrong spot. Imagine how hard it will be
to clean behind a faucet that’s right up against a backsplash. Not only will
the controls likely to be impaired, but water (and grime) will collect behind
the faucet and won’t be easy to clean. Faucets and sinks are used multiple
times a day, so creating a situation that irritates and annoys a client almost
guarantees dissatisfaction and bad word-of-mouth.

Plumbing fixtures like faucets, sprayers and soap dispensers
come in all shapes and sizes. Every fixture is different in some way, and
sometimes that difference is significant. Generally what’s important about a
fixture is the part the client never sees. The portion of the fixture that
serves to mount it to the countertop actually is more important to you than
what is visible.

The mounting stem (the part that penetrates the countertop)
defines the size of the hole and whether that hole can be drilled or cast. If
it’s too short to fully penetrate the countertop (and allow the mounting nut to
be installed), a recess in the underside of the countertop must be cast to thin
the concrete where the faucet will be installed. I call this “mushrooming” the
hole. The hole is smaller at the top surface of the concrete, to accommodate
the visible portion of the faucet, and larger at the underside of the concrete,
to allow the plumber to reach up into the concrete to tighten the mounting nut.

Neglecting this is can be a painful mistake, because it may
be the plumber who discovers that the faucet can’t be mounted. Having to grind
out a recess after everything else has been installed is perhaps the hardest
and messiest thing to do, since you’re on your back inside the cabinet, with
all the dust and debris from grinding falling onto you from above.

Generally it’s the mounting hardware (the nut and its washer
– shown as a dotted red line in the diagram above) that dictate how close the
faucet can be mounted to the sink.

Remember that the washer shouldn’t overlap the sink flange
(shown as a dotted green line in the diagram above). It’s best to leave about
¼” between the sink flange and the biggest washer so that the sink can be
centered during installation and not interfere with the plumbing fixtures when
they are mounted later. The largest washer dictates the distance between the
sink and the center of the fixtures’ holes, since most fixture holes are
located the same distance from the sink.

Careful planning of the location of the sinks, faucets and
other fixtures ensures a smooth installation and a happy client. Not only will
all the parts work together as they are expected to, a well-planned layout of
the sink and the other plumbing fixtures results in an aesthetically pleasing
assembly that is easy to keep clean and looks good.