Fitting external AAV

[Jethro_uk]

Our soil stack is sited in our back yard, right next to the internal corner of our "L" shaped bungalow. Currently it's a cast iron abomination which is angled to go under the eaves, and then about 60cm into the air.

I want to replace it with an external air admittance valve, which will be terminated about 180 cm above the ground - well above any sink in the house.

Tempting as it may be to just chop off the cast iron at 180cm with an angle grinder, and stick an AAV into it, I suspect SWMBO wouldn't be happy ;)

So it's really a question of what might be involved in removing the iron pipe, and replacing with a uPVC jobbie.

I am presuming that when I loosen the cast iron pipe, and remove it carefully (ideally straight up) I will find it has _somehow_ been joined to a ceramic pipe of some description.

What is the best way to join the new uPVC pipe into that union ? Is there a finned rubber seal ? Magic mastic ?

[Jethro_uk]

p.s. how heavy should I expect a 9-10 ft cast iron pipe to weigh ?

[Robin]

New 100mm pipe would be around 30kg. (Hence I've chickened out of replacing it here.) And old stuff might be thicker/heavier.

[Nightjar]

Good luck with that. The fixings are probably well rusted into place.

Almost certainly cemented in. You may find it easier to avoid breaking the clay pipe if you chop the iron pipe off a short way above the join, remove the main part, then tackle the iron to clay joint.

PVC soil pipe to clay adapter; essentially a big rubber gaiter.

Depending upon wall thickness, 4" cast iron pipe is 8-12lbs/ft, so you are looking at around a hundredweight, more or less.

[harryagain]

The way it will likely be connected is with bit of tarred rope (gaskin) in the socket of a clay pipe to centre up the cast iron pipe and then a cement fillet. You might get lucky & it may just pull out. You might find the socket has cracked (quite likely due to the weight of the cast iron pipe.) If the joint is sound, you can cut the cast iron pipe off and cunningly make use of a WC connector (you might have to butcher it a bit) to connect in the PVC pipe. There are also flexible rubber pipe thingys with long SS jubilee clips to do the job on none standard pipes.

[Fredxxx]

I was unaware you are now allowed external AAVs!

[Tim+]

Curious why you want to replace a reliable system with a dodgy AAV.

Tim

[ARW]

I was going to say the same - however I saw one at work the other day and the BCO said certain ones were allowed.

Or in simple terms - the new fangled "external AAVs" are not the same thing as just "externally fitting an AAV"!

[ARW]

[Mr Pounder]

He said it looks shit. Or words to that effect. We do not have a soil stack. Seems we send our shit to the pikey next door to vent.

[Bob Minchin]

My back of envelope jottings suggests about 125gram per cm or 12.5kg per metre.

[ARW]

So you do live in a pikey area then?

[ARW]

It's not the weight that is the problem (you seem to agree with Robin at somewhere between 30 to 37kg) - it's the centre of balance/gravity of the vertical pipe and where the OP is stood if he tries to move it.

Basically half of this

[Mr Pounder]

Not at all. The tosser catman (with no cats) next door brings the street down though by his scruffy house with dirty windows. He won't bother bringing his wheelie bin in until the afternoon. Every street has a pikey living in it. I love to show him up with my house. He has made a clothes prop out of a branch cut from a tree! The entire family are odd, council estate stock really.

[ARW]

Yet they live next door to you.

[Tim Watts]

I was going to say - surely they would be prone to freezing shut?

You are allowed to take the soil stack vent in 82mm pipe (I did) so you could replace your external pipe with something perhaps more streamlined...

[Fredxxx]

The reason why I thought they were not allowed, was that air should also be allowed to escape, to allow the ventilation of sewers. Of course an AAV would be one way. Neutral pressure and all that.

I guess it also depends on where the OP is with respect to his neighbours' pipes and any requirement for ventilation and two way "breathing" for the system as a whole.

[Andrew Gabriel]

Have you got another vent somewhere to let excess pressure out?

[John Rumm]

Traditional fixing method was to chisel a squarish tapered hole into the wall, and then drive in wooden plugs (or sometimes the brickie would actually build the wall with the wood plugs in place).

The large spike on the "clip" then hammered into the plug spreading it like a modern expanding sleeve anchor fitting. Very firmly fixed when in place, but they let go relatively easily *if* you can get them moving. The best tool usually being a mattock - slip the wide blade behind the pipe near the fixing point and leaver it away from the wall.

Indeed.

A cast to cast joint would usually have the internal pipe end bound with cord or rope to form a seal and then a mortar or other "mastic" used to seal and flaunch the join.

Wicks do internal and external versions.

[Robin]

Does anyone still pour molten lead? That was what was used on all the LCC pipe around here in the 50s/60s. And I've never quite worked out how they managed to pour all the "horizontal" joints for wastes and then lift the whole lot up and into position.