Green Building Forum - Need help! Still got condensation after all my efforts!!

Need help! Still got condensation after all my efforts!!

deniance — Thu, 24 Dec 2020 13:10:04 +0000

Hiya guys! Me again!
Last year I posted here about insulating my attic!
I was getting lots of condensation on the felt which was dripping down into the insulation!

Well.... I thought Iâ€™d fixed it, sealed all holes and penetrations and was thinking it was good!

Just been up there this morning and itâ€™s exactly the same!! Just as bad as before!!

Any ideas what else I can do or even some method of monitoring where itâ€™s coming from?

Only 3 rooms upstairs, one is a bathroom, so, Iâ€™ve ...

Made an insulated hatch with a sealed lid
Sealed all cable penetrations
Checked the bathroom fan connection
Sealed all wall plates of internal walls
Foamed up gaps
Sealed any gaps in coving below

All of the above were massive sources of air from the house getting into the attic, used a fan to find all the leaks, I also bought a box of 50 lap vents that you slide in the felt, you can see daylight through some of them and there is very good airflow , you can feel it and see the cobwebs blowing about!! But there is still enough air condensing to overpower this! Just canâ€™t figure out where!

I thought all the work I did would make it less but itâ€™s just as bad as before! Like someoneâ€™s gone up there with a hosepipe and misted it all!!

All I can think of is, the chimney wall as it passes through the roof does get a bit soaked when itâ€™s raining, not dripping wet but just soaks up the moisture and the bricks turn dark, I wonder if the log burner flue dries it off and this then evaporates and floats across the attic and condenses again? Only had the burner on for two days so Iâ€™m doubting this theory!
Or maybe because itâ€™s a terraced house, I wonder if itâ€™s floating over the top of his attic and making it into my side??

Gotta try and sort it out, everything is going mouldy!!
Any ideas folks? Cheers

Need help! Still got condensation after all my efforts!!

bxman — Thu, 24 Dec 2020 13:30:05 +0000

can any air get in at the eves?

or get out at the ridge?

how about a link to last years post

happy Christmas everyone

Need help! Still got condensation after all my efforts!!

deniance — Thu, 24 Dec 2020 13:51:47 +0000

Yeah, I emptied the loft, I made plastic trays to go in the eaves to leave a gap for air to flow, I donâ€™t have eaves on my house though, itâ€™s stone walled and the roof timbers just sit on top of the wall but Iâ€™ve left airflow gaps anyway, I did this in every bay all around the attic, I then put a fan downstairs and found the air leaks, swapped spotlights to normal lights and sealed light penetrations, I also sealed switch penetrations, I sealed all the edges with foam, I sealed all the internal wall plates where ceiling plasterboard met walls, few other random holes, sealed all coving in rooms below, bought a new bathroom fan, itâ€™s taped sealed around the duct, Iâ€™ve checked this and thereâ€™s no air leaking, itâ€™s not blocked either, I built a raised and insulated loft door collar and draught proofed it. Itâ€™s also very draughty you there, I put a lap vent at eave level at middle and top of each rafter bay on both sides!!

There is a digital aerial just hanging in the loft and it is covered in drips of water so I know itâ€™s condensation from the house!! Just canâ€™t figure out from what! Itâ€™s gotta be quite severe to overcome the ventilation, the bathroom fan extracts through the wall and is right over the other side of the house so itâ€™s not coming back into the roof

Iâ€™m just clutching at straws but itâ€™s either, a massive hole Iâ€™ve missed, the rain dampened chimney wall drying out and recondensing or next doors humid air making its way over the top of the roof wall into my side?

Iâ€™ll see if I can snap a few pictures later

Need help! Still got condensation after all my efforts!!

philedge — Thu, 24 Dec 2020 14:09:06 +0000

If moisture is coming over the party wall from next door then they are likely to have condensation too. Can you see over or ask them to have a peep? Thats assuming they are well insulated and have a cold attic space.

If theres damp penetrating below the chimney flashing through porous brickwork then that will be adding to the humidity in the attic space as it dries out. To eliminate that as a source you could wrap the stack in plastic sheet and tape it all up for a couple of weeks to see if the attic dried up.

Need help! Still got condensation after all my efforts!!

deniance — Thu, 24 Dec 2020 14:23:28 +0000

I canâ€™t See over the wall but itâ€™s not to say thereâ€™s a gap, Iâ€™ll investigate today
Iâ€™m thinking itâ€™s the wall drying out adding to the humidity but when you see how much condensation there is makes you wonder if it is that? But I guess itâ€™s gotta be one of these, so so process of elimination !
Iâ€™ll take some pictures soon! Thanks

Need help! Still got condensation after all my efforts!!

jms452 — Thu, 24 Dec 2020 14:43:43 +0000

Sounds like you are doing sensible things that will also make your house warmer and more comfortable when you finally solve it so don't loose heart!

Where are you in the country?

Need help! Still got condensation after all my efforts!!

tony — Thu, 24 Dec 2020 14:51:09 +0000

It is not too much of a problem getting it so long as it goes away again.

Desperate measures would be to fit a fan to suck air out of your loft , this would be replaced by drier air from outside, clearing any damp, possibly only needed during cold weather

Need help! Still got condensation after all my efforts!!

deniance — Thu, 24 Dec 2020 15:02:02 +0000

Posted By: jms452Sounds like you are doing sensible things that will also make your house warmer and more comfortable when you finally solve it so don't loose heart!

Where are you in the country?

Iâ€™m in South Wales, Cardiff ish

Need help! Still got condensation after all my efforts!!

deniance — Thu, 24 Dec 2020 15:05:28 +0000

This is a picture of the chimney running through to the roof, itâ€™s hammered down for 2 days non stop and this is a small patch that has made its way from the stack to below roof level, itâ€™s not big or soaking wet but might be an issue

Need help! Still got condensation after all my efforts!!

deniance — Thu, 24 Dec 2020 15:06:12 +0000

This is the chimney in question

Need help! Still got condensation after all my efforts!!

deniance — Thu, 24 Dec 2020 15:07:07 +0000

This is the white horrible stuff growing

Need help! Still got condensation after all my efforts!!

deniance — Thu, 24 Dec 2020 15:08:30 +0000

This is the lowest section close to the eaves, it has a vent and is dripping onto the insulation

Need help! Still got condensation after all my efforts!!

deniance — Thu, 24 Dec 2020 15:09:18 +0000

There is air blowing through the vents for sure

Need help! Still got condensation after all my efforts!!

deniance — Thu, 24 Dec 2020 15:11:38 +0000

This is the opposite side of the roof, the side the sun rises on, the mouldy side pictures are on the cold side of the roof as in, where the sun goes down

Need help! Still got condensation after all my efforts!!

deniance — Thu, 24 Dec 2020 15:16:45 +0000

Posted By: tonyIt is not too much of a problem getting it so long as it goes away again.

Desperate measures would be to fit a fan to suck air out of your loft , this would be replaced by drier air from outside, clearing any damp, possibly only needed during cold weather

I know , I thought I had it cracked, I found a cable penetrating the plasterboard of the bedroom , only a 10mm hole but all the surrounding insulation was soaking from it and a little water up the wall right next to it, so I knew it was just a case of sealing the attic up and venting it , I found dozens of leaks, foamed up, caulked up, tubes and tubes of the stuff! It hasnâ€™t made a blind bit of difference ! So annoying!!! But I wonâ€™t let it beat me! Thermal camera is currently on charge ! Iâ€™ll investigate soon!

Need help! Still got condensation after all my efforts!!

revor — Thu, 24 Dec 2020 16:33:57 +0000

What are your ceilings made from would they be lath and plaster?. I once had a Victorian house and replaced some of the lath and plaster ceilings with duplex board (foil backed plaster board) particularly the bathroom. Just with living in a house causes a phenomenal amount of moisture which will find way through ceilings if porous including plasterboard. It can often happen that when you insulate a loft area it becomes that cold that the high humidity air getting in there condenses out and the ventilation in the loft area may not be sufficient to move it. What is the ventilation in the living areas?. A work colleague never had trouble with condensation in his loft until he put extra insulation in there. He found out about it when water started dripping through the ceiling fitting in the bedroom. The vapour was not just going up through the light fitting in the bedroom but through all of the ceiling.
Prior to the extra insulation the loft was warm enough so that the air did not get to the dew point.

Need help! Still got condensation after all my efforts!!

deniance — Thu, 24 Dec 2020 16:56:45 +0000

Posted By: revorWhat are your ceilings made from would they be lath and plaster?. I once had a Victorian house and replaced some of the lath and plaster ceilings with duplex board (foil backed plaster board) particularly the bathroom. Just with living in a house causes a phenomenal amount of moisture which will find way through ceilings if porous including plasterboard. It can often happen that when you insulate a loft area it becomes that cold that the high humidity air getting in there condenses out and the ventilation in the loft area may not be sufficient to move it. What is the ventilation in the living areas?. A work colleague never had trouble with condensation in his loft until he put extra insulation in there. He found out about it when water started dripping through the ceiling fitting in the bedroom. The vapour was not just going up through the light fitting in the bedroom but through all of the ceiling.
Prior to the extra insulation the loft was warm enough so that the air did not get to the dew point.

It was lath and plaster but now itâ€™s normal plasterboard with emulsion paint

It is house air condensing just canâ€™t pinpoint it, thought Iâ€™d stopped the majority but something is still allowing a lot up there!

Need help! Still got condensation after all my efforts!!

djh — Thu, 24 Dec 2020 17:22:14 +0000

bxman asked: "how about a link to last years post"

I suspect it was the epic at
http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16335

Need help! Still got condensation after all my efforts!!

djh — Thu, 24 Dec 2020 17:26:53 +0000

Posted By: tonyDesperate measures would be to fit a fan to suck air out of your loft , this would be replaced by drier air from outside

Not necessarily if the loft space is open to next door's as well.

Need help! Still got condensation after all my efforts!!

jms452 — Thu, 24 Dec 2020 17:32:18 +0000

Posted By: denianceemulsion paint

Kitchen and bathroom paint is more of a vapour barrier than emulsion - and easier than foil backed plasterboard.

That said after the efforts you have put into stopping warm wet air from inside getting into the loft space my suspicion would shift to liquid water coming in from outside, warming up in the sun then condensing in the cold evenings.

Posted By: deniance Iâ€™m in South Wales, Cardiff ish

So wet and windy then...

...and in that first photo water is coming in from the roof.

have you got photos of the roof (particularly that area) from the outside?

Do the neighbours in the terrace have similar issues?

Need help! Still got condensation after all my efforts!!

deniance — Thu, 24 Dec 2020 17:43:07 +0000

Posted By: djhbxman asked: "how about a link to last years post"

I suspect it was the epic at
http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16335" rel="nofollow" >http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16335

thatâ€™s the one!

Need help! Still got condensation after all my efforts!!

tony — Thu, 24 Dec 2020 18:13:36 +0000

I donâ€™t like the continual water/wet coming in via chimney, you are fighting a loosing battle with a source of wet , please can you post a pic showing the outside of the chimney please.

Need help! Still got condensation after all my efforts!!

deniance — Thu, 24 Dec 2020 19:20:31 +0000

Posted By: tonyI donâ€™t like the continual water/wet coming in via chimney, you are fighting a loosing battle with a source of wet , please can you post a pic showing the outside of the chimney please.

Iâ€™ll get one tomorrow

Need help! Still got condensation after all my efforts!!

deniance — Thu, 24 Dec 2020 19:22:51 +0000

Ahh hahah!!! Found a possible source!! Bit of heat source when viewed inside the attic!

Need help! Still got condensation after all my efforts!!

deniance — Thu, 24 Dec 2020 19:24:07 +0000

A cold spot from below

Need help! Still got condensation after all my efforts!!

deniance — Thu, 24 Dec 2020 19:25:10 +0000

A torch placed above reveals the gap

Need help! Still got condensation after all my efforts!!

deniance — Thu, 24 Dec 2020 19:26:47 +0000

I used a plywood sheet as the hatch lid, it has bent slightly and now sits above the white draught strip, need a fatter seal or some sort of clasp to pull it closed!

Need help! Still got condensation after all my efforts!!

bxman — Fri, 25 Dec 2020 17:25:47 +0000

We hear there is a good storm coming in Sunday if you can get up there and check the wind is not driving water up the under the slates/tiles

Or put a sheet of plastic temporarily over the top of your insulation so that it can pool in the middle .

And then go up the following day and see if it has caught any rain that has been blown in .

It could be that .

Need help! Still got condensation after all my efforts!!

revor — Fri, 25 Dec 2020 19:36:10 +0000

If you do not manage to solve problem with what you are doing so far this gyproc sealer could solve your problem. It forms a vapour barrier to prevent problems such as yours.

https://www.british-gypsum.com/products/gyproc-drywall-sealer?tab0=0

Need help! Still got condensation after all my efforts!!

tony — Fri, 25 Dec 2020 19:49:26 +0000

I donâ€™t think that is stops water vapour.