"IMM" wrote in message
...

"Harv" wrote in message
...
Hi all,

The Problem :-

I have a conservatory style plastic roof over a room on the side of the
house. The waste stack runs up the inside corner of this room, and out
through the current roof, where much flashband has been applied to stop
it
leaking.

However the current roof is a very poor consruction, nearly flat and
only
10mm thick. Oh, and it leaks too.

The plan is to replace the whole roof with a self supporting UPVC system
with 25mm thick multiwall glazing, increasing the slope of the roof at
the
same time.

With the increased slope, it would be sensible to fit an air admittance
valve above where the toilet connects into the stack, but the valve
would
actually be below the level of the trap in the hand basin. All of this
would
be inside the room, but the stack would not need to penetrate the new
roof.

Is this likely to cause any problems?
Presumably the valves do not allow any odour to escape?
Any experiences of doing something like this?

Thanks in advance!

Harv,

Don't use an air admittance valve. Put an inspection cap above the toilet
on the stack. I assume the basin is pied into this stack around where the
wc is connected to the stack. You only need to use a Hepworth HepVo trap
on the basin, nothing else.

See the web site:
http://www.hepworthplumbing.co.uk/hepv1.htm

IMM,

This looks a great idea which I'd never have thought of.

I've seen the hepvo traps at the plumbers merchants, but didn't realise they
could be used in this manner. Is this in breach of building regs at all?

Also, I hadn't mentioned, but my neighbours toilet/basin also feeds into the
same stack, presumably the one hepvo valve will be snough to deal with this?

The only problem I can ever see is if some smart alec ever moves in and
replaces the hepVO with a conventional trap, at which point, a trap from one
of the 2 baths, 2 basins and 2 toilets would get syphoned.

Many thanks,

Harv