|Building Codes: Before you begin a
plan for your bathroom, check your state and local building
codes. Plumbing codes are often written and enforced at the
city or county level. Many small towns or rural areas have
no building codes at all. These areas may depend on county
health departments, which are more interested in well and
septic guidelines, than plumbing.
Permits: If you are planning to install a water
heater or make an upgrade in your plumbing that will require
changes or additions to your piping, visit your building
inspector and apply for a permit.
You will need to fill out a permit application, which will
be a guideline for your inspector.
Inspections: Generally you will need two inspections;
one after the rough in work is completed, and one after the
project is completed. The rough in inspection will check on
all plumbing and repair work before you cover it with
plaster walls or tile.
New home inspections will require an inspection of
underground water service and sewer lines, after the
installation of an under-slab or basement floor, the rough
in inspection, and the final inspection.
Layout: When planning your bathroom, there are a
number of factors to consider. The first is where is your
current plumbing? It is a good idea to cluster your plumbing
together, near your main stack of pipes. It can be very
expensive to run piping far from your main zone of
plumbing. Toilet drains, especially, are costly and time
consuming to move. One of the most efficient methods of
planning your plumbing is to put two bathrooms back to back
where toilets, sinks, or tubs share a common wall.
Next, you need to know how much room each fixture will take.
Most fixtures come in standard sizes, but if you order a
custom piece, be sure and get the rough in measurements from
Plumbing Layout - Toilet: Most toilets fit in a 22
space, but code requires a 30 opening in which to fit the
toilet. Even if you dont have a code, you will want to
follow this suggestion; as cleaning a toilet in a tight
space can be very cumbersome. When planning where your
toilet drain will go, ensure there is 15 on either side of
the center of the drain to the nearest wall or cabinet. The
center of the flange should be 12 ½ out from the back stud
wall or 12 from a finished wall.
The water supply for the toilet can come up through the
floor or from the back wall. For a floor water supply, it
must be centered 6 to the left of the drain and 3 in from
the back wall. A wall water supply requires it to be 6 to
the left of the drain and 6 from the floor.
Sink & Vanity Layout: Drains can be centered inside
the vanity space, allowing the drainpipe to extend about 18
off the bathroom floor. Hot and cold water pipes can be
installed 2 on either side of the center line of the sink
top, making them 4 apart, and should extend about 24 into
the vanity. Dont make the mistake of mixing up your hot and
cold pipes. Cold is on the right, hot on the left.
Although the standard height of most vanities is 32, many
people prefer a higher vanity height, up to 36, for ease of
use. To add the height to a standard vanity, simply place it
on a frame of 2x4s and adjust the height of the fixtures
If you are installing a 2 sink vanity, divide it into two
sections and treat them each as a separate vanity for
plumbing, as they will each require their own water outlets
Plumbing Layout: Check your manufacturers
specifications, as the sizes of bathtubs vary with design.
In any case, measure the drain in the center of the tub,
cutting and 8x12 opening into the floor to accommodate the
waste and overflow assembly, as this can be bulky to
install. The P-trap should be installed after the overflow
Standard height for a tub faucet valve is 28 off the floor,
but if you have your tub on a platform, remember to allow
for the height of the platform. Place the water outlets 8
apart, or 4 from the center. If you are installing a shower
in your tub, the height of the shower head can be placed
anywhere from 72 to 76, depending on your preference.
Shower Layout: New showers can vary in size from 32
square to as much as 5 or 6 feet square, depending on your
preference. The larger showers eliminate the need for a
shower door or curtain; both of which are mold and mildew
collectors, so you may want to consider a larger shower for
Standard shower valve height is about 48 above the floor,
with the shower head placed anywhere between 72 and 76
high. Shower plumbing should always be installed in a side
wall for easier access, never a back wall.
Drain placement is usually centered to the shower floor;
however, if your shower is large, you may wish to place the
drain closer to the shower stream.
The floor opening for the drain should be 6 to 8 square to
allow for the pan or 1 piece stall before connecting the
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