Zen83237 wrote:


"Lobster" wrote in message
...
Zen83237 wrote:
I am remodelling my kitchen and the most logical place for the tumble
dryer is against an internal wall. Can it be vented up and out a flat
roof. The washing machine can empty the waste water into the soil pipe in
a planned toilet/shower room. I planned to vent the toilet out through
the flat roof so was wondering if the tumble dryer can vent out the same
place. I need to ensure that the hot air from the tumble dryer doesn't
vent back into the toilet.
Never a good idea to have vents like this through a flat roof; lots of
scope for leaks. Certainly possible though.

Pretty sure you wouldn't be allowed to combine the toilet and tumble-drier
vents but Building Regs gurus here may know better.

My first thought though is are you sure you need the vent even for the
toilet - ie, have you looke into the possibility of fitting it with an
air-admittance valve instead?
http://www.screwfix.com/prods/78150/Plumbing/Soil-Vent/FloPlast-Push-Fit-Air-Admittance-Valve-Grey?cm_re=SEARCHPROMO-_-AIR-ADMITTANCE-_-78150
May or may not be possible depending on various factors; however maybe
you've already been down this road?

This is a medium to long term plan that will involve building a kitchen
extention and toilet shower room. I am trying to visualise the options
before getting any plans done. I don't quite understand how the air
admittance valve works so I need to look into that.

Where conventionally you would have a soil stack venting upwards, you'd
basically cap it off with an AAV rather than have it go up through the
roof. It uses the fact that you don't (necessarily) need to let air
*out* of the system, but you do need to let air *in* to avoid vaccuum
formation and the toilet not flushing etc. The AAV is a one-way valve
which lets that happen, ie without letting gas out of sewer into your
house; and would be a no-brainer in your scenario provided it's
appropriate... there are several conditions eg you can't be at the end
of the run of your sewer; at least every 3 or 4 houses(?) has to have a
fully open vent etc.

David