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Condensation in Loft

garyi said:
tony if you dont mind me asking what sort of price range we talking here lol?
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In the £6-8k region I think, may end up a bit higher. This is for a pretty generic three bed Victorian end terrace, the type with two living rooms and an extra gable for the bathroom/kitchen at the back. This is to get the felt replaced, any less than good tiles replaced (not a whole new modern roof), proper ventilation etc and obviously involves full scaffolding which will be a good chunk of the cost. I’ve got a roofer I trust who has done good work for me previously for well over a decade so I’m not shopping around. The roof is now at the stage he reckons just patching problems as they happen isn’t economical so I’ll just get it done right.
 
Yeah fair enough.

I think the first stop will be dislodging much of the shit from up there. When it warms up. Also redo the insulation its all terrible, then take a view on the roof. Not a lot I can do right now. I went to see what the patch was and can see nothing of note up there!
 
garyi said:
Yeah fair enough.

I think the first stop will be dislodging much of the shit from up there. When it warms up. Also redo the insulation its all terrible, then take a view on the roof. Not a lot I can do right now. I went to see what the patch was and can see nothing of note up there!
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100 mm between the ceiling joists, 200 mm over the top at 90 degrees - you probably know that. You'll need to lag any pipes too to prevent bursts with there being less ambient heat up there.
 
gavreid said:
A lesson that I've learned (the hard way) with a house - always start with the roof before spending any significant money on anything else...
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Yes just like us our houses need a good hat and boots i.e. make sure that it can effectively shed water from above and effectively drain it away from its base.
 
Vinny said:
People get very hung-up about under-felt.

It is a recent invention, presumably associated with use of concrete tiles???? No traditional slate roof (or any other traditional roof covering) originally had under-felt - the tiles went straight onto battens that went straight onto the roof trusses. Going into a loft under them was/is filthy, cold and like looking at a starry sky during daytime.
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My Edwardian terraced house had no felt, just tiles onto battens and plenty of sky visible between them. Very cold up there in winter (lots of insulation between the joists though) but we never had any problem with rain water getting in and obviously it had a great deal of ventilation!
 
1. Find and repair any leaks
2. Ensure bathroom extractors etc are not blocked
3. Find the ventilation (typically soffit vents or airbricks) and ensure clear and not blocked by insulation
Short term, you can dry the place out by leaving the loft hatch open for a couple of hours. Best done before you go out for obvious reasons.

My parents had this, it needs resolving. Things started going mouldy up there. Their fix was to put in soffit vents, all done.
 
gavreid said:
100 mm between the ceiling joists, 200 mm over the top at 90 degrees - you probably know that. You'll need to lag any pipes too to prevent bursts with there being less ambient heat up there.
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Don't forget not to bury electrical cables in the insulation
 
This guy does beautiful work if you like YT videos. This one's an old slate roof, nearly all of them broke coming off...


 
I have a similar problem
We had the house refurbed in 2009
Half the roof is original half new
We have had water coming in, found to be broken tiles or badly installed gulleys

Keep fixing the tiles and other problems or bite the expensive bullet and take the roof off and start again ?
Allied to that we have far too many draughts and insulation gaps

A cheap thermal image camera shows some frightening pictures
 
Glad to hear we are not the only ones! Although we have had this problem for around 10 years and ever since we had the boiler changed to a combi and the water storage tank removed from the loft. We contacted the 'so called experts' around about a year later when we first noticed the problem, they advised we have some additional ventilation put in the loft, which we did at a cost of around £500.00 - it didn't make a jot of difference and at the time, we didn't get them back in, not sure why, may be as it was approaching the warmer months where we didn't require the heating on. I have since done as others have recommended on here, and pulled away any insulation that might have been blocking the eaves, still made no difference.

The house I believe was built in the 70's (would need to double check) and is a typical 3 bed detached with single garage, it has this horrible plastic lining on the inside of the loft roof where the condensation runs down and drips from. I am sure this is needed, but I'm no expert so couldn't say what for. I'll post a pic and short video I took recently when I have more time as we tried to see if it had improved during the December cold spell, but it hadn't, wishful thinking! The only thing that we have found, as a cheap and cost free solution, is to leave the loft latch open. Not fully, just at a bit of an angle with about a 4-6 inch gap. This is not good for keeping the house warm though as all of that lovely heating goes straight out, but it does keep the roof dry and we figured is cheaper than a new roof!

If anyone can recommend a roofing expert, that is trust worthy and not a rip off merchant, in the Nottingham area do let us know as I'll happily call them out for advice and to see what can be done. I hate having the loft hatch open all the time - October - May depending on how warm it is. It shouldn't be necessary and when the wind is blowing strong and in a certain direction you get the upstairs smelling of that lofty, fusty smell, which is not pleasant.
 
stevec67 said:
1. Find and repair any leaks
2. Ensure bathroom extractors etc are not blocked
3. Find the ventilation (typically soffit vents or airbricks) and ensure clear and not blocked by insulation
Short term, you can dry the place out by leaving the loft hatch open for a couple of hours. Best done before you go out for obvious reasons.

My parents had this, it needs resolving. Things started going mouldy up there. Their fix was to put in soffit vents, all done.
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All of this. You can also add ventilators at the ridge, which tend to work well since wind movement over the ridge reduces pressure inside the roof, helping ventilation draw.


The sarking materials used as underlay these days is deliberately made vapour-permeable to deal with these issues.
 
I added extra insulation last year and noticed we had condensation up in the loft space, I quickly realised I had covered the soft fit vents on one side. Once I'd pulled it back to free up the vents, the problem went away.
Modern roofs need airflow from one side to the other.
 
Roofs always did, to protect the timbers; you must keep timber moisture content under 20% to avoid decay from a range of sources.
On clear nights the roof covering temp drops markedly - radiation to the clear night sky - and condensation forms on the underside of tiles/slate etc/
the sarking is there to deal with this - and wind-driven rain & snow penetration. So clear space above the sarking, below the covering that is ventilated, is needed.

Insulate the loft well, and this happens more often since the space is colder; you may even get a little interstitial condensation in the top of fibrous (mineral wool, glass wool ) typ insulants - and this is easily analysed. But with a sufficiently ventilated space, this kept down below a level where it can accumulates and cause issues.Hence the move to using vapour -permeable sarking membranes (these also make use of the vast amount of small airgaps between tiles and slate to carry-away damp air and wind-driven moisture, and so make clear air paths at eaves and ridge much less critical, to a marked extent)

Keeping the airspace under the 'tiles, and above the insulation well-ventilated, is essential, regardless of how the roof / loft/room-in-roof etc is configured.

Oh - and check the gutters are clear and free-draining; leaks inwards from these, even simply wind-driven because they are ponding locally, is a classic source of problems.
 
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Not read all the replies, will do after tea, but you’re not alone @garyi, ours has become a bit fusty smelling, I need to get rid of loads of junk up there, I thinks this isn’t helping, also I need to check ventilation as has been said.
 
Hello



Had this when I first moved in property it had been unouciped for four years wasn't sure if it was just damp.hot summer followed come winter loft ringing wet off timbers and felt and stuff stored in it also, fitted vents to the soffit lots of them its a bungalow no noticeable improvement then had some tiles replaced with vented ones damp gone and not been back, the insulation is probably a couple of feet thick. My mothers bungalow is now damp in the loft although never before,we live in the south east England probably just keep an eye on hers for the mean time.



Regards



Stuart
 
Lots of good advice regarding the need for ventilation. The better your loft insulation is, the colder the loft space and the worse the condensation.
I used to get it in really cold weather with moisture forming on the felt and dripping off.
I fitted a bunch of these to increase ventilation and so far much better.
I paid around £2 each for them
https://www.amazon.co.uk/gp/product/B00M9ILJPG/?tag=pinkfishmedia-21
 
This site contains affiliate links for which pink fish media may be compensated.
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