Waste vent pipe - which trade?

[dementedpixie]

We have a waste vent pipe that vents out of the roof. We keep getting dampness from it that is soaking through the insulation and making the ceiling wet in the shower room below. Have plumbing cover through British gas but they say they don't cover that part of the system. Had a handyman out who said it could be due to gaps in the felting that the roof tiles sit on so he filled them in. Unfortunately tonight I have noticed a slight bulge in the ceiling paint again and it feels damp. On A previous occasion was told it was due to a build up of condensation on the soil waste pipe but don't know how to fix it. Also I'm scared to go in the loft myself as it isn't floored and had insulation so I'm scared I'll go through the ceiling.

What trade would I need to look at it? Plumber, roofer, builder? I don't want dampness in my loft or holes in my ceiling due to water.

Probably a roofer. Pipes that go through roofs have a special "tile" with a hole in it to fit the pipe.

example but there are many
Don't allow anyone who mentions sticky flashband into your home.

Is it a flat roof? Different trade.

Ask around for a personal recommendation, or look for roofers working nearby and speak to the householder. Advertising websites are not a good source.

p.s.

I hope you haven't got an extractor fan blowing steam into your loft.

I don't think the issue is the tile itself but the flexible pipe that attaches to the vent in the roof and to the soil pipe coming up through the floor of the loft. It is that pipe that we were told had condensation on it. Our roof vent is more like this

No our extractor vents through the wall

Its this sort of pipe that connects the tile vent to the solid waste pipe

Is that a rigid pipe with flexible rubber connectors, or is it a flexible plastic hose like you get on a tumble drier?

There should not be condensation in a loft, because it should be cold, dry and draughty, with lots of ventilation. A soilpipe in a loft should not be very cold so should not get condensation on it. It is normally hard, rigid plastic, and vertical.

However, a badly fitted extractor fan pipe can get internal condensation, because it is full of warm steam.

Could the pipe you are think of be a ventilation duct? The type of "tile" you show is the type used for ventilation such as extractor fans. So is the flexible hose. If they hang in saggy loops, condensation can collect inside them and leak out.

It's a flexible hose but bigger/wider than a tumble drier/extractor hose. All extractors vent through the walls. We have 2 of these vents connected to hoses and did have problems with the other one too that hadn't been connected properly and ended up with water coming through my dd's ceiling. I can't remember who sorted that one but it involved them propping up a dip in the hose with a bit of rope! I'm not entirely sure what vents through the front one tbh. Wonder if it would be solved with rope too!

please try to post some pics.

I suppose if it's pipes and ducts a plumber could do it.

Rigid pipe is much less prone to these problems than the flexi hoses.

I am not convinced that your problem is the soil pipe.

These are the best pictures we could get from the loft hatch area. I'm thinking those bends on the pipe aren't helping. Do you think condensation builds up and drips of the elbow near where the black flexible pipe attaches?

Possibly. I can also see a water pipe. Perhaps that is leaking as well. It should be lagged against freezing.

The elbow is drooping down. It looks like 110mm soil pipe (4 inch) which is normal.

I'd suggest changing the elbow to a 135degree bend, so it rises diagonally rather than (not quite) horizontally.
www.plumbase.co.uk/osma-soil-4-bend-135-4s163g-100010665-3568707

then any condensation will run down the pipe. And if correctly installed it will not leak from the joints.

It could have a few wooden supports fixed to the roof timbers to hold it up and prevent sagging.

The current installation is quite a bodge. It should be possible to do away with the flexy and do it all in rigid pipe, which is less troublesome.

I'd try to get a personal recommendation for a wrinkly local plumber. Provide your photos when explaining the problem.

S/He will probably say it sounds like an extractor fan duct.

Do please come back afterwards and tell us about the fix.

Apparently the piping on the other side is an even worse bodge job! That one has stopped dripping now though so I don't care!

@PigletJohn, had dyno plumbing out (they have the contract with British gas but I wasn't using them under that as they don't cover soil waste pipes so it was chargeable). Elbow changed to one with a washer in as old one didn't have one (he said drip was from where the pipe met the elbow). Pipe and hose now supported so that it doesn't droop over time like the last one. Hopefully it helps and my ceiling dries out - how long do you think it will take?

Some photos for you too. (The tape is just to prevent hose detaching from pipe as it has happened in the past too)

Ceiling plaster is thin so it dries quickly (within a week) but you need to lift the insulation away as it holds damp. The roof timbers will take longer.

The plasterboard looks damaged and I think you will need it replaced and the ceiling replastered (this is cheaper than you think). Foil-backed plasterboard is more resistant to occasional slight water.

The ducts/pipes still look pretty bodgy.