Sewer Vent - Building Regs Requirement

[Peter Hemmings]

Hi,

I moved into a house with a side extension garage which has a flat roof on top of about 6 feet of tiles set at 45 degrees. The original flue outlet from the side of the house has been cut just below the flat roof and diverted through a vent in the tiles. The roof space is a bit cluttered with the pipe and I thought I would fit a vent valve and remove the pipe across the underside of my roof. I was told some time ago that I could only do this if there was a "free vent" elsewhere on the property. Could someone confirm this is so and if so why is it necessary?

Thanks

[Set Square]

I assume you don't really mean "flue", but soil stack.

The sort of valve that you can use to terminate the stack in the roofspace is a one-way affair, which lets air *in* but not *out* - otherwise you'd get nasty smells! You can only use these when there is another vent, which is open to the atmosphere - within a certain distance (but not necessarily within your property), to prevent pressure build up.

I'm sure others will quote chapter and verse. Otherwise, consult a Building Inspector at your local council's Building Control department. They'll tell you what you can and can't do.

[Hugo Nebula]

On Thu, 15 Jul 2004 21:19:02 +0100, a particular chimpanzee named Peter Hemmings randomly hit the keyboard and produced:

By 'flue', I presume you're not talking about a boiler or other combustion appliance's flue but a vent pipe for a drain. If the latter, then you can have it vented using an air-admittance valve (a.k.a. a 'Durgo' valve), provided that your drainage is connected to a vented sewer not a septic tank, and that all your neighbours haven't done the same (see

and do a search for the certificate). If you're installing it in an unheated space, don't throw away the polystyrene 'cap' that comes with it. It's not packaging, it's needed to prevent the seals freezing and perishing.

[Christian McArdle]

Presumably so that when the thing jams up for the nth time, the sewer will still be able to vent.

Christian.

[Lobster]

Interestingly when I was doing a similar thing to you, one BCO said I had to have a full soil stack up through the roof, and another one (incidentally the one who is now giving me grief over windows etc!) overruled him saying that it was fine because next door had one, and that's how it was fitted.

Peter, have a google for a thread here entitled "Dergo valves , ventilation, and BCOs" which I started earlier this year - I got some very helpful responses which explained the whole issue very clearly. (And I also learned it's spelled "Durgo"!)

David

[Peter Hemmings]

snip

Thanks, I also learned a lot from the thread.