Major condensation in loft space
Discussion
TheLastPost said:
There's your answer: the sun is warming the roof slope and dispersing the condensation, I would suggest.
I've moved the boxes out of the way so I'll see if that has any influence on it. The sun is shaded for the earliest part of the morning, so I'm not sure that's the sole reason. We shall see.
Here we go again. Absolutely soaking loft.
Since last year I laid a VCL under the insulation draped between the joists, laid plastic sheet over the top of the insulation to keep it dry and fitted a new bathroom fan, vented out to a roof tile via the loft (all seals well taped). I also vastly reduced the stuff in the loft, now three only a few boxes.
I also tried the cheapskate trick of inserting little blocks of foam insulation in the gaps of the roof membrane, which I felt did marginally improve airflow.
I need to sort this before next year or else it'll halve the roofs lifespan.
I have 6 roof tile vents, almost no eaves ventilation due to the way it was built (no overhang) and a non breathable membrane (the last of the non breathable types).
Ridge vents on the list next, whatever the cost.
Since last year I laid a VCL under the insulation draped between the joists, laid plastic sheet over the top of the insulation to keep it dry and fitted a new bathroom fan, vented out to a roof tile via the loft (all seals well taped). I also vastly reduced the stuff in the loft, now three only a few boxes.
I also tried the cheapskate trick of inserting little blocks of foam insulation in the gaps of the roof membrane, which I felt did marginally improve airflow.
I need to sort this before next year or else it'll halve the roofs lifespan.
I have 6 roof tile vents, almost no eaves ventilation due to the way it was built (no overhang) and a non breathable membrane (the last of the non breathable types).
Ridge vents on the list next, whatever the cost.
iamrcb said:
Here we go again. Absolutely soaking loft.
Since last year I laid a VCL under the insulation draped between the joists, laid plastic sheet over the top of the insulation to keep it dry and fitted a new bathroom fan, vented out to a roof tile via the loft (all seals well taped). I also vastly reduced the stuff in the loft, now three only a few boxes.
I also tried the cheapskate trick of inserting little blocks of foam insulation in the gaps of the roof membrane, which I felt did marginally improve airflow.
I need to sort this before next year or else it'll halve the roofs lifespan.
I have 6 roof tile vents, almost no eaves ventilation due to the way it was built (no overhang) and a non breathable membrane (the last of the non breathable types).
Ridge vents on the list next, whatever the cost.
This article raises alarming possibilities:Since last year I laid a VCL under the insulation draped between the joists, laid plastic sheet over the top of the insulation to keep it dry and fitted a new bathroom fan, vented out to a roof tile via the loft (all seals well taped). I also vastly reduced the stuff in the loft, now three only a few boxes.
I also tried the cheapskate trick of inserting little blocks of foam insulation in the gaps of the roof membrane, which I felt did marginally improve airflow.
I need to sort this before next year or else it'll halve the roofs lifespan.
I have 6 roof tile vents, almost no eaves ventilation due to the way it was built (no overhang) and a non breathable membrane (the last of the non breathable types).
Ridge vents on the list next, whatever the cost.
Daily Telegraph property section
Article said:
I’m afraid this is another situation – like cavity wall insulation – where the government has been hoodwinked by the green lobby, and by “man-made climate change” hysteria, into promoting a cheap and disastrous policy that will damage hundreds of thousands of homes.
We have a rental property that seems to suffer from condensation on the outside walls and in the loft when the tenants dry their washing on radiators and take showers without using the trickle vents (and in one case, blocking up the airbrick 'cos it was draughty and costs more to heat').
Since it's almost impossible to make tenants do the necessary to properly ventilate the property (it's a one-bed town house, so it's mainly 20-something 'professionals' who just want a place to crash and have just moved out of home, often not the best at looking after other people's property) we're looking at a PIV system, as recommended by one of the agents we use - they've seen very good results in a lot of the houses they manage and the system isn't too expensive or difficult to install.
Description here http://www.fixmyroof.co.uk/videos-and-guides/conde...
The one we're thinking of installing is http://www.nuaire.co.uk/our-products/residential/p...
We reckon it's worth a go, given the cost of redecorating and the shortened lifespan of roof timbers if we let it continue.
Since it's almost impossible to make tenants do the necessary to properly ventilate the property (it's a one-bed town house, so it's mainly 20-something 'professionals' who just want a place to crash and have just moved out of home, often not the best at looking after other people's property) we're looking at a PIV system, as recommended by one of the agents we use - they've seen very good results in a lot of the houses they manage and the system isn't too expensive or difficult to install.
Description here http://www.fixmyroof.co.uk/videos-and-guides/conde...
The one we're thinking of installing is http://www.nuaire.co.uk/our-products/residential/p...
We reckon it's worth a go, given the cost of redecorating and the shortened lifespan of roof timbers if we let it continue.
Mark Benson said:
We have a rental property that seems to suffer from condensation on the outside walls and in the loft when the tenants dry their washing on radiators and take showers without using the trickle vents (and in one case, blocking up the airbrick 'cos it was draughty and costs more to heat').
Since it's almost impossible to make tenants do the necessary to properly ventilate the property (it's a one-bed town house, so it's mainly 20-something 'professionals' who just want a place to crash and have just moved out of home, often not the best at looking after other people's property) we're looking at a PIV system, as recommended by one of the agents we use - they've seen very good results in a lot of the houses they manage and the system isn't too expensive or difficult to install.
Description here http://www.fixmyroof.co.uk/videos-and-guides/conde...
The one we're thinking of installing is http://www.nuaire.co.uk/our-products/residential/p...
We reckon it's worth a go, given the cost of redecorating and the shortened lifespan of roof timbers if we let it continue.
Interesting.Since it's almost impossible to make tenants do the necessary to properly ventilate the property (it's a one-bed town house, so it's mainly 20-something 'professionals' who just want a place to crash and have just moved out of home, often not the best at looking after other people's property) we're looking at a PIV system, as recommended by one of the agents we use - they've seen very good results in a lot of the houses they manage and the system isn't too expensive or difficult to install.
Description here http://www.fixmyroof.co.uk/videos-and-guides/conde...
The one we're thinking of installing is http://www.nuaire.co.uk/our-products/residential/p...
We reckon it's worth a go, given the cost of redecorating and the shortened lifespan of roof timbers if we let it continue.
Any idea how much?
Wouldn't this also force warm air back into the loft via the "positive pressure" and thus increase the loft condensation problem, even if it fixes it in the rest of the house? (I speak as a layman, as you can probably tell
)Also been experiencing insane amounts of condensation in my loft space - some of the roof trusses are now sodden with condensation!
I was going to install a few roof vents to try and get some air moving through the loft space - but looking at the link above that may not work.
The old lady who lived in my house prior obviously took up some free insulation offer and there is absolutely loads of it up there - which has also be stuffed right down into the eaves which won't be helping. Problem is due to the shallow pitch on the house its almost impossible to even get to the eaves to pull it back.
Has anyone had any luck with roof vents?
I was going to install a few roof vents to try and get some air moving through the loft space - but looking at the link above that may not work.
The old lady who lived in my house prior obviously took up some free insulation offer and there is absolutely loads of it up there - which has also be stuffed right down into the eaves which won't be helping. Problem is due to the shallow pitch on the house its almost impossible to even get to the eaves to pull it back.
Has anyone had any luck with roof vents?
I discovered a dripping wet loft when getting the decorations down in late November.
Its insulated, and has vents in the soffit (not by us, is rented). Turns out I was a dick and stuffed it too full during the summer, had things wedged up against the felt, going right back down the corners etc. After a few hard frosts, with the roof staying frosty on one side, sun on the other it obv started to condensate inside.
Fixed it by having a bloody good clear out, sort out and repacked the loft so it was all in the middle, leaving the edges clear. 2 weeks later it sorted itself out, and there's a nice strong draught up there now!
Swmbo was f
ked off with me, daughters Moses basket and some clothes caught mould, so we binned them (Moses basket was unsaveable, £140 present from my dad too...)
Its insulated, and has vents in the soffit (not by us, is rented). Turns out I was a dick and stuffed it too full during the summer, had things wedged up against the felt, going right back down the corners etc. After a few hard frosts, with the roof staying frosty on one side, sun on the other it obv started to condensate inside.
Fixed it by having a bloody good clear out, sort out and repacked the loft so it was all in the middle, leaving the edges clear. 2 weeks later it sorted itself out, and there's a nice strong draught up there now!
Swmbo was f
ked off with me, daughters Moses basket and some clothes caught mould, so we binned them (Moses basket was unsaveable, £140 present from my dad too...)Having freaked out in dec when I got the decorations out and it was raining inside the loft while I was up there, I decided there wasn't anything wrong.....
We had been drying loads of stuff ready for Xmas, sheets, towels etc. The heating had been on for 3 days solid and it was about 3 deg c outside.
I realised the dripping started after I got up there - it had to. If it was dripping like that before, the ceiling would have come down already yet the boxes were only wet on top. Stuff inside was dry.
It was all just the wet air inside the house blasting up into the cold roof space.
We had been drying loads of stuff ready for Xmas, sheets, towels etc. The heating had been on for 3 days solid and it was about 3 deg c outside.
I realised the dripping started after I got up there - it had to. If it was dripping like that before, the ceiling would have come down already yet the boxes were only wet on top. Stuff inside was dry.
It was all just the wet air inside the house blasting up into the cold roof space.
Interedting thread. I have bought a new property, a 1960's built bungalow which does suffer from condensation on the windows when cold. A neighbour confirmed they do suffer with this and they run a couple of dehumidifiers to control it.
I have looked at mvhr but more to try and make it more asthma friendly, I ended up buying a nuaire 365 unit which is one of the positive input ventilation units, basically just pumps air from the loft into the house to promote air changes and control the humidity level. It has been running for a couple of days and the atmosphere in the house feels better but time will tell.
Quite easy to install but needs a big hole in the ceiling for the vent, the supplied ducting is all insulated stuff and easy to sort out. I bought the soffit kit as well but haven't fitted this yet as it is a tad cold outside. The unit has 6 fan speed settings but is very quiet, currently set to 2 and I can't hear any noise from it all, power consumption is also low, max power is 24W.
I have looked at mvhr but more to try and make it more asthma friendly, I ended up buying a nuaire 365 unit which is one of the positive input ventilation units, basically just pumps air from the loft into the house to promote air changes and control the humidity level. It has been running for a couple of days and the atmosphere in the house feels better but time will tell.
Quite easy to install but needs a big hole in the ceiling for the vent, the supplied ducting is all insulated stuff and easy to sort out. I bought the soffit kit as well but haven't fitted this yet as it is a tad cold outside. The unit has 6 fan speed settings but is very quiet, currently set to 2 and I can't hear any noise from it all, power consumption is also low, max power is 24W.
Esseesse said:
Couldn't the answer to these cold wet roofs be to keep the existing insulation, but also add some beneath the felt/tiles? This might raise the temperature in the loft by 2 or 5 degrees and prevent the dew?
Air movement is the way. Any source of warmth in the loft will effect it too. Shower extract pipe work doesn't help. Airflow carries the moisture out, cross venting is all. The amount of ventilation we install now, in combination with good breather membranes eradicates the issue totally.
Most older roofs will have a 1f under slating, and insulation stuffed everywhere. Recipe for disaster.
Bluebarge said:
Mark Benson said:
We have a rental property that seems to suffer from condensation on the outside walls and in the loft when the tenants dry their washing on radiators and take showers without using the trickle vents (and in one case, blocking up the airbrick 'cos it was draughty and costs more to heat').
Since it's almost impossible to make tenants do the necessary to properly ventilate the property (it's a one-bed town house, so it's mainly 20-something 'professionals' who just want a place to crash and have just moved out of home, often not the best at looking after other people's property) we're looking at a PIV system, as recommended by one of the agents we use - they've seen very good results in a lot of the houses they manage and the system isn't too expensive or difficult to install.
Description here http://www.fixmyroof.co.uk/videos-and-guides/conde...
The one we're thinking of installing is http://www.nuaire.co.uk/our-products/residential/p...
We reckon it's worth a go, given the cost of redecorating and the shortened lifespan of roof timbers if we let it continue.
Interesting.Since it's almost impossible to make tenants do the necessary to properly ventilate the property (it's a one-bed town house, so it's mainly 20-something 'professionals' who just want a place to crash and have just moved out of home, often not the best at looking after other people's property) we're looking at a PIV system, as recommended by one of the agents we use - they've seen very good results in a lot of the houses they manage and the system isn't too expensive or difficult to install.
Description here http://www.fixmyroof.co.uk/videos-and-guides/conde...
The one we're thinking of installing is http://www.nuaire.co.uk/our-products/residential/p...
We reckon it's worth a go, given the cost of redecorating and the shortened lifespan of roof timbers if we let it continue.
Any idea how much?
Wouldn't this also force warm air back into the loft via the "positive pressure" and thus increase the loft condensation problem, even if it fixes it in the rest of the house? (I speak as a layman, as you can probably tell
)Costs about £300 plus fitting I think for the version with a heater (to warm very cold air in winter - which we feel is important so that tenants don't disconnect or block the vents), not that it seems difficult to install - as gottans says above, the big downside is a large hole in the ceiling.
Gottans - I'd be interested in how you feel it's helping, if any - please try and keep us updated. We're thinking of having one in our house too (early '70s bungalow, we don't have terrible condensation but our daughter has a chronic lung illness so airflow is important).
Air movement is the key. I had this issue a some years ago in a 13 year old house, people were telling me I needed more ventilation, air bricks in the gables, the house is going to fall down, the world will end, etc. All the normal internet hysteria.
None of them asked what type of house it was, and being mid terrace, air bricks in the gables was a touch tricky...
What bugged me, was why did it start. I'd lived there for three years with no issue, then all of a sudden, condensation. So, something must have changed to cause it. So I sat down and thought about it, a couple of months beforehand the girlfriend moved in, there was quite a lot of extra stuff to fit in a two bed terrace, so it had to go in the loft. Without thinking about it I had put it all width ways across the house, being terrace the only ventilation was at the front and back.
Bingo. I'd blocked the airflow.
I cleared a load of stuff out, and arranged the rest against the side walls length ways. Problem solved.
None of them asked what type of house it was, and being mid terrace, air bricks in the gables was a touch tricky...
What bugged me, was why did it start. I'd lived there for three years with no issue, then all of a sudden, condensation. So, something must have changed to cause it. So I sat down and thought about it, a couple of months beforehand the girlfriend moved in, there was quite a lot of extra stuff to fit in a two bed terrace, so it had to go in the loft. Without thinking about it I had put it all width ways across the house, being terrace the only ventilation was at the front and back.
Bingo. I'd blocked the airflow.
I cleared a load of stuff out, and arranged the rest against the side walls length ways. Problem solved.
Have to say this thread is interesting, I live in a new build persimmon home, around 4 years old, every single house here has condensation in the loft and its pretty bad. I've spoke to a roofer who has said that he has been fixing these roofs for years, he said 2 things, permissons are using non breathable felt and also we require 4 vent tiles. So on tuesday 4 vent tiles are being fitted and hopefully it helps.
Well last year the roofer couldnt come so vent tiles didnt get done. Its that time of year again, -4 outside and one side of loft bone dry and one wet, dripping from felt. Im convinced air flow is fine, it is cold in the loft, should i open the loft hatch to let hot air up or should i do the opposite and put in more insulation, surely its one or the other.
tolmie35 said:
Well last year the roofer couldnt come so vent tiles didnt get done. Its that time of year again, -4 outside and one side of loft bone dry and one wet, dripping from felt. Im convinced air flow is fine, it is cold in the loft, should i open the loft hatch to let hot air up or should i do the opposite and put in more insulation, surely its one or the other.
Has the insulation been pushed right up to the eaves ? Persimmon have been speccing vented eaves/ridge for some time now. Can’t see how they would benefit from a non breather membrane, but they do have some slashers working for them.tolmie35 said:
...one side of loft bone dry and one wet, dripping from felt....
That's screaming 'microclimate' at me.There are two mechanisms to be aware of: solar orientation is the obvious one (the side of the roof that gets the sun will be warmer, and less prone to condensation), the other perhaps less so...
I've mentioned on other threads (but not this one, it seems) that part of the problem can be aerodynamic. A pitched roof acts like a very crude aerofoil to the wind flowing over it: a low pressure bubble forms over the lee slope. Low pressure = low temperature, so the airflow cools the roof structure, causing condensation on the inside surface. In this case, increasing roof ventilation actively and very dramatically makes the situation worse, as you're just feeding a nice, continuous flow of damp air across into the roof to have its moisture condensed out.
Obviously, the 'perfect storm' is where you have a roof slope that is both north facing and in the lee of prevailing winds, so I'd be checking both those things as a possible cause.
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