9668 Soil Stacks

HI, I'm new to the forum, just bought a shell of a house in Abruzzo (anti-seismic reinforced concrete pillars and roof) my question is about soil stacks because we need to start designing where bathrooms will go. The house is in a village so I assume we are on mains drainage and the soil stack will be internal - in the UK soil stacks have to be vented above the roof line but I haven't noticed that in Italy. Does anyone know the regulations about this?

Category
Building/Renovation

Hello Celanese and welcome.

You really need to have a chat with your local, friendly geometra - or if you prefer, you not-so-local expensive architect. He (or she) will be able to advise you accurately as far as the local interpretatation (and any local "bye-laws) of the soil pipe vent. You are quite correct in that soil pipes here do not tend to vent anywhere near the roof line, as in the UK. Many things are very different, hence the need for local help.

Good luck with your project!

Thanks Nardini,
Yeah I've got a very local and luckily not so expensive architect and I'm going to talk to him about this soon, just wanted to be armed with as mu. ..ch info as possible. Have got to plan the first bit of the project which involves adding a chimney, so if soil stack needs to vent through the roof I wanted to do it all at once

Don't get confused by the 'role' of a soil stack. You will probably need one even if you aren't on mains drainage

It isn't to let smells out - it is to allow air to enter the system when loos are flushed, to stop the system 'siphoning' when a loo is flushed, [if the system syphons when flushing, U-bends anywhere in the house. (loos but most probably sinks), can get emptied and smells allowed into rooms]

If you need a stack, it can terminate in the roof space, with an 'non return valve' on its top, which allows the air in but not out.

[I installed a downstairs loo in my last UK house, with the stack terminating inside the room [with a non-return valve on it]. It passed all Building Regs/Planning Permission requirements]

For what it's worth, our house has three bathrooms and three kitchens and not a single soil stack of the British sort. Nor is there any other sort of vent arrangement that's visible inside or out.

The only unpleasant smells we've had was due to the U-bend on one of the bathtubs drying out after not being used for a couple months last summer. Running the tap for a few seconds sorted out the problem.

Additional possibly pertinent details: (1) Work was done on plumbing here in 2001, so things are presumably not too far adrift from current building regs. (2) We have a septic tank.

Al

The reasons which alan h gives for venting the stack are not valid when you have a system with a 'soil' pipe which serves only the wcs, and a waste pipe which serves all the other things (sink, shower, bath, wash machine, bidet, shower etc).

This is the current requirement in Italy, and the soil pipe will discharge to the septic tank, then the outflow from the septic tank plus the waste water will discharge into the mains drans or a private disposal arrangement.

Do not assume that you can avoid a personal septic tank simply because you have mains drains close by.

Allan Mason describes a smell which no doubt many of you have experienced returning after a long absence to your Italian home. That is usually evaporation loss from the trap, and as Allan says, fixable by refilling the trap with water (running the tap for a couple of seconds). Nothing whatsoever to do with presence or lack of soil pipe venting in a modern installation.

Hi Celanese,
They just don't seem to use them over here.... we have just had the house rebuilt (the bosses) six bathrooms and not a vent pipe or air admitance valve. No back siphonage......no problems at all. puzzles me as well. The drainage/sewage is all sealed. There are inspection manholes but the pipes have screwed access covers and the manholes covered over. Very unlike the uk but it means you can say goodbye to rodding (very welcome) In the (very) unlikely event of a blockage the system can be pressurised but it just doesn't happen.
John.