Vent pipe problem

[cw55]

Hello,
I'm trying to buy a flat at the moment but there seems to be a problem with damp in the roof.

My surveyor has said this is due to the vent pipe from the bathroom actually ending in the loft (rather than going through the roof) leading to lots of condensation and then drips and damp. A roofing contractor has previously been round and said the damp is due to a capillary reaction in the roof. However neither surveyor nor contractor want to talk to each other.

Does anyone know whether it is possible to ever have a vent pipe exiting in a loft or does it always need to be outside? And therefore is the vent pipe the more likely explanation for the damp and the roofer talking rubbish.

cheers.

 

[doitall]

I'm surprised you have to ask.

An extract fan in the bathroom is to take out steam, as well as smells etc, if you dump it in another space then obviously that space will be damp from condensation.

 

[cw55]

sorry am new to this and am no expert!

I meant the vent pipe from the drainage/plumbing system not the extractor fan. so it needs air in to let the toilet flush etc. its this vent pipe that exits in the loft.

 

[Goldspoon]

I think you need to let us know what this pipe actually is and where it comes from...? A vent pipe SHOULD go into the loft and should, if things are not working completely correctly, dump water into one of the tanks in the loft.

A vent pipe does not cause any condensation or damp problems.

 

[tryitandsee]

You are quite right, it's the soil and vent pipe.
Yes it should be vented to the outside to allow the steam etc. created from the bath/shower/basin waste water to escape into the atmosphere.

If it is in the roof space then a durgo valve may/should have been used, allowing air in but not allowing smells/air out. Perhaps this valve is faulty or not there, but any 'surveyor' would have pointed that out to you.

It does help to allow a certain amount of fresh air into the loft space generally to avoid condensation problems. Make sure your insulation is not packed tight up into the rafters at the outside walls, as this is where the ventilation starts from.

Im sure your roof pitch was done correctly at he time of building and water capillary is probably a red herring, the underfelt should carry this away in the event of very strong winds if it did penetrate under the tiles.

I would ask the roofer to remove a few tiles and extend the soil and vent pipe up through the roof, the skill being making it watertight, problem solved.

 

[cw55]

great - thanks tryitandsee - that's very helpful!

evidently my surveyor didn't pick up on the durgo valve.

I take it this would be a cheaper option (although not ideal) - if we were to make sure it had a good working durgo valve and then see if the damp improved then we wouldn't need to bother extending it through the roof?

 

[tryitandsee]

Durgo's work ok, that's just the situation they were designed for. It's just better to get to the outside and forget it forever.

 

[tryitandsee]

How boring is this, googled 'durgo valve' and it's on youtube, I really must get out more.


http://www.youtube.com/watch?v=zPO3B64C5cY