Perhaps not a surprise, Mrs K found some ice on the felt, damp beams and boxes when getting the Christmas decs out.
Our loft is vented under the eve's but I guess the cold weather + central heating has caused this and we are moving boxes around to maximise the flow ventilation.
Its one thing after another with houses isn't it... what can you do!
If you open the loft hatch regularly this can occur. Draught proofing the loft hatch can also help
You'll always get this, as long as you have ventilation up there not much else you can do.
Happened to us as well fitted some ventilation spacers in the roof felt lining and so far the condensation has not reappeared.
https://www.google.com/search?client=safari&rls=en&q=loft+felt+condensation&ie=UTF-8&oe=UTF-8
Draught proofing the loft hatch can also help
Indeed. It doesn't help that the section in particular has the bathroom underneath, with ceiling spots which are of course holes in the ceiling leading up to the roof...
You’ll always get this
I imagine it happened before but we didn't notice, we've been here 10 years and of course its been just as cold before. The roof beams aren't rotten sp hopefully we'll have the 10 more years we need before its time to move house without replacing the roof!
You can probably get some over-fascia vents in from a ladder. Just lift the tiles and felt up above the fascia board, 25mm so barely noticeable
Just found exactly the same issue in our loft. The cheapskate builders used nasty shed roofing felt (might not be but looks like it) under the tiles and the condensation forms on that and then drips. I'm wondering about putting something between the roof trusses, maybe a the metallic bubble wrap to try and stop the warm air hitting the cold felt. Either that or wingspan between the trusses but that looks expensive. Already have a lot of insulation on the ceiling of the upstairs rooms which might be blocking the air flow but given it's minus three here I think it's warm moist air hitting the cold felt. Might try to improve the insulation around the loft hatch as well.
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At this time of year with snow on the roof, ice dams can form. This can in some situations cause damp to find its way under the roof tiles.
https://extension.umn.edu/protecting-home-rain-and-ice/dealing-and-preventing-ice-dams
Really mean of cheapskate builders to fit the non breathable membrane. Just looked up price and breathable is 4x the price. Our roofer replaced the bituminous type, it was so rotten it pretty much disintegrated when u touched it. Breathable membrane is waterproof too.
I patched up roof loads of times before reroofing, damp creeps along trusses and always in most inaccessible places.
Since reroofing no leaks or damp.
Exact same issue made worse after adding insulation. It’s the lack of venting/ cold profile that causes the condensation. Should have a vapour barrier on the warm side of the insulation. Main cause of vapour was the ensuite and light holes. So I painted the ensuite ceiling with 2 layers of gloss then one of matt. Then boxed in the light fittings above (led so no heat) so anll sealed and the problems gone. Moisture stays in the room / re evaporates and goes out the window rather than into the loft.
Planning similar to munkyboy. Seal off all holes and go a step further fitting MVHR. Hopefully it'll mean no more open windows at night!
If you don't have a breathable membrane, these seem a good solution to add ventilation to the roof void. Also capping off any lights in bathrooms is a must.
Felt lap vents
We have exactly this issue. Old house, solid walls, cold roof and a gas bill that's taken on a life of its own. There's only 100mm of insulation under boards so a few years back I added a 300mm of sheep's wool. It ended up going mouldy thanks to all the condensation (removing that was a fun Boxing Day job I'll not forget). I had a few tile vents added but we still get condensation, and until that's fixed I dare not add more insulation. I can see from the monitor that it's currently 3 degrees and 99% humidity up in the loft, no wonder there's a problem! These felt lap vents look like a good idea, so I've just ordered 20 and will report back.
Thanks for the tip STWers.
Ideally you need to limit the moist air getting in the loft from below, even if you seal all the gaps you can still get vapour getting through the plasterboard and plaster if you dont extract much from the wet rooms. As others have found adding more insulation can make it worse as the cold loft gets even colder. Vapour barriers are in need but need to be fitted perfectly with no pockets for the moisture to get trapped and then condense on the barrier if there are any areas not quite insulated properly. I check from time to time as I have a stupid amount of insulation in the loft and sealed up every little hole and crack I can find but there is always that nagging doubt. I have no vapour barrier either.
I spent a fun afternoon yesterday trimming and refitting the hose that connects the fan unit of the shower extractor fan to the external vent. Went up to get the Xmas decorations and everything was wet. Looks like the builder had attached it with tape which dried out and fell off at some point.
Every time someone showered it was blowing wet air into the loft and this cold snap meant it was all condensing up there.
I've used tape for now but will get some proper hose clamps ASAP.
We've had similar after adding insulation, discovered the insect mesh on the eaves vents was all blocked up, hoovered up both sides internally and wire brushed one side, still got to do the other but massively increased amount of ventilation in the loft.
Luckily I hate down lighters, so removed them & sealed up the holes in the bathroom ceiling years ago.
Had this problem in my last house, fitted a handful of those plastic vents along each side of the roof and problem solved.
It's also worth bearing in mind that even if you have sufficient ventilation up there, there's hardly been a breeze for the last week or so to actually blow through it and draw the moisture away. The air outside is still, cold and damp. Not a lot that you can do in that situation other than maybe set a fan going in the loft to move the air round a bit but that still won't pull it outside.
I'm keenly following this thread, discovered we have the same problem again this winter. It seems the LAP vents we fitted didn't do much. I think our insulation is pushed into the eaves, so that's my next task to check.
We had this last year.
Couple of years previous the roof tiles were replaced and they put a vented ridge on.
Unfortunately, the guys that put the OSB on didn't get the memo and butted the OSB at the ridgeline.
Had to get the company back and they put some vented tiles in.
Seems to have solved the issue
Now waiting on a PIV fan to arrive to see if that can cure the condensation issue in the rest of the house!
It’s also worth bearing in mind that even if you have sufficient ventilation up there, there’s hardly been a breeze for the last week or so to actually blow through it and draw the moisture away. The air outside is still, cold and damp. Not a lot that you can do in that situation other than maybe set a fan going in the loft to move the air round a bit but that still won’t pull it outside.
It seems the LAP vents we fitted didn’t do much. I think our insulation is pushed into the eaves, so that’s my next task to check.
Hmm, I rather let at buying some lap vents from Amazon. Bearing in mind this is the first time we seen it, maybe I should have wait for the temps to change / wind to blow first. We do have under eve venting around all sides.
I did also have insulation rammed right into the eaves blocking up the venting there, pulling that back did help a bit but it was the lap vents that cleared the issue.
