My house was built last summer with drains prepped in the basement for
a bathroom; a toilet and sink drain were placed and the concrete was
cut where a shower would be placed. What will I need to do to connect
to a vent for the sink? How difficult is it to install the trap for
the shower? Finally, if I connect a second sink for the bar to the
drain for the bathroom sink, how should I connect the vent?
Some pipe and fittings, dope, and a good saw. Not very. With fittings.
Plumbing is a code restricted process in most states, and for good reason.
You should hire a licensed plumber.
But if you insist on DIY there are many good books that describe basic
plumbing principles and procedures. I see them in the big box stores. Your
questions suggest that you do not have even a basic concept of plumbing
principles. A recipe for disappointment. Get some basic knowledge and you
will have all of your answers, including the ones you haven't asked yet!
Are you saying that someone went to the trouble of roughing in bathroom
drains, but did not rough in the vents nor the trap for the shower?!?
When we built our home over two years ago, a basement bathroom was
roughed in and all three (shower, sink, toilet) have their own vent. The
trap for the shower is part of that rough-in.
It depends on how far that sink is from the connection to the vented
drain. Basically, the drain pipe from a sink must slope down about a
quarter of an inch per foot of run. The drain must be vented at a location
that puts the vent connection no lower than half the diameter of the
pipe lower than the height of the trap. That means, if it is 1.5" pipe,
the vent connection must be no lower than 0.75" and with a 0.25" per foot
slope, this is three feet.
If the connection is farther than this, you will have to run a vent that
remains higher than the flood level of the bar sink until it drops to
connect with the drain.
"I really think Canada should get over to Iraq as quickly as possible"
For venting the sinks: after the trap on each sink, the drain pipe will run
back horizontally, usually into the wall behind the sink. At that point it will
turn down to connect to the waste system. Place a sanitary tee at the point it
heads down. The down leg goes to the waste, the up leg is the vent. It must run
vertically until it is 6" above the top of the sink. 42" above the floor is
usually specified. Then it can turn horizontal to connect to the existing vent
Here is a great forum for plumbing advice, read through the old posts, there
are lots of questions answered and photos posted:
If you want to drain the bar sink into the bathroom drain, if can
only be a few feet away or you might have to vent it too.
They do make a venting piece that doesnt require you to
vent it outside. (I forgot the name of the unit, but its
real popular to use when installing a sink into an island
in a kitchen.)
Only catch about that piece is that you need to have access to
it because the rubber flapper needs to be changed every few years for
One word of caution. If you get the permit, by procedure or law, all permit
info is passed to the Tax Assessor. Any improvements will be duly noted by
the taxing authority and your taxes will probably go up as a direct result.
I made the mistake of getting a building permit for some temporary roof
repairs and I have been paying higher taxes as a result of that permit.
The flip side: Buyers get more savvy every day. One of my neighbors has been
upgrading his house without permits for years. Retired, went to sell, and
some dick-head went to the Town Hall and discovered that the plans on record
did not match the house for sale. Our town has a by-law that requires work
without a permit to be inspected at double the cost and then incur charges
for back assessments. Informed the broker, who must disclose what she knows,
and was able to beat him down on the price. It was basically extortion. Be
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