Toilet Vent ?

comadi, Mar 16, 5:59pm
Anyone know if there is a minimum height above the roof for these !
There is a bit of rust around the flashing on mine, and I will be putting a new sheet of iron up; so it would be great to bring the vent up the outside wall and under theeve, with 2 x 90 degree bends and have the vent cap sitting about 150 mm above the spouting line.

Doing away with another hole and flashing in my roof.
rak1, Mar 16, 7:57pm
Use an air admittance valve and you dont need to go up through the roof.
raven71, Mar 16, 8:21pm
Yes, 600 mm above the under side of your eves.
comadi, Mar 17, 8:07am
Thanks, can these air admittance valves be put in the ceiling
Going down to Bunnings soon, will inquire there.
rak1, Mar 17, 10:03am
Doubt that you can purchase these from a hardware store. Usually get them from Plumbing World. Mico Pluming etc. Wouldnt recommend putting them in the ceiling.
raven71, Mar 17, 10:27am
Bunnings sell 32/40 mm and 40/50 mm air admittance valves. You need to have at least one vent on your property to let sewer gasses escape. Air admittance valves only stop negative pressure in the system.
comadi, Mar 17, 3:02pm
Yes Bunnings had the small ones, but you guessed it my vent pipe is 80 mm.
The info sheet said they they can be put in the ceiling as long as you are 150 above any insulation, more on available space soon.

The ex plumber at Mitre 10, who said he had installed them told me they are available in larger sizes and are designed for ceilings.
Basically when you flush the suction pulls the spring loaded seal down and lets air in and when the flush stops it seals again.

It will be tight for me though as I have just found out I have approximately 230mm of space when I pull the batts away.
Given the larger ones will no doubt require more clearance it's going to be close.
d.snell, Mar 17, 3:46pm
Did you read the message above from raven71! If this is your only toilet, you must have a vent. Air Admittance Valves are not enough as they don't vent sewer gases from the pipe, all they do is improve flushing.
comadi, Mar 17, 4:37pm
Is there a trap below the vent T off (underground) to stop mains gases !
How can a valve improve flushing over an open pipe with no restrictions whatsoever !

Cheers.
d.snell, Mar 17, 5:18pm
If that was your only vent, then you can't just replace it with an air valve. You need to have a vent somewhere to exhaust sewer gas build up.
A trap won't stop gasses, it will only slow them down, once the gas builds up enough, it will bubble through a trap.
comadi, Mar 17, 5:35pm
Ok, thanks. It looks like Ill be stuck with a roof flashing then :-)
d.snell, Mar 18, 8:33am
So why can't you do as you said in your first post! Up the outside wall and around the eve!
trade4us2, Mar 18, 8:50am
I have a vent with mushroom cap down by the road, and a vent pipe from the toilet goes up two stories just above the roof. When I was painting the house there was such a nasty smell coming from the vent that I put half a Coke bottle over the top. The toilet still flushes OK. There is another toilet pan in an outhouse that I have not used for years. I suppose that is now acting as a vent!
d.snell, Mar 18, 9:23am
Not sure what the regs are, but something like 10 metres or similar (someone will correct me if I am wrong) is the maximum distance for unvented, so if the two toilets are within cooey if that distance, 1 vent will suffice. .
If the vent was 2 storeys up or even only 1 storey, you shouldn't notice any smell from the vent at ground level and as it was doing what it was supposed to do, so there wasn't any need to put a coke bottle on it.
trade4us2, Mar 18, 10:35am
The two toilets are 4 metres apart. I suspect that the water in the bowl of the unused toilet has now evaporated. Therefore it's now acting as a vent.
Access to that toilet is extremely difficult, in case that is not obvious. So nobody can get in there.

I still have to finish painting the house and the roof, so of course I am working near the top of the vent that I have mostly blocked off.
d.snell, Mar 18, 12:42pm
The vent is on the sewer side of the water in the bowl, so I would suspect the outhouse toilet has an external vent pipe going up the outside of the outhouse, so it will vent both toilets, especially if the 4m is correct. As far as flushing the inside toilet, I would suspect there is enough volume of air in the vent pipe going up 2 storeys to allow efficient flushing.
comadi, Apr 23, 11:09pm
I would still consider it, but if the vent has to be 600 above the eve, I think it will make the house look like one of those hillbilly hippie buses :-D
I was thinking of terminating it discreetly at the top of spouting height, but what with the regs, and I dont want to risk any smell coming back into the bathroom & toilet windows.