Heavy Loft Condensation

Discussion in 'Floors, Stairs and Lofts' started by KanielDemp, 29 Nov 2021.

  1. KanielDemp

    KanielDemp

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    Hi all

    I hope you're all keeping well

    This is my first post and I'm hoping to get some advice on a case of extreme condensation in my loft. I've read the various threads I could find, but wanted to get your take on the solutions I've been offered by several roofers before taking the plunge.

    I live in a small, two bedroom detached bungalow, that was built around 20 years ago. I moved here last Winter and when I first moved in, I discovered a major issue with condensation in the loft. It was across the entire length of felt, but only on the side that doesn't get any sun in the Winter. It was also more localised above the two coldest rooms in the house - the bathroom and kitchen.

    Towards the tail end of last Winter I installed throughout the loft some basic air vents that slide in between the felt folds and open it up to allow airflow. This significantly increased airflow and reduced the condensation problem, but did not eradicate it entirely. Prior to this, the entire half of the roof impacted was dripping wet and my insulation, beams and few boxes I had put up there were drenched. After the vents were installed, it reduced it to a point it was okay and then Spring was on its way. It seemed to dry up and I hadn't paid it any more thought.

    I'd since forgotten about it, then last week a damp patch appeared on my ceiling and I popped my head up for a look and again, the felt was absolutely soaked through and dripping. Not as bad as it had been previously at its worst, but still soaking in places. (I'll try to include some some photos in the thread. They're a bit murky, but the lighting isn't the best up there.)

    A few things I can rule out as per comments on existing threads:

    I can confirm the bathroom is always sufficiently vented after a shower, with the window in fact being kept open throughout most of the day. Same for the kitchen if any cooking is done. I don't use the extractor fans as I believe they not fitted correctly, so any moisture escapes directly out the windows and it clears very quickly. I also always open my bedroom window for a couple of hours in the morning to clear any condensation that may have formed on my windows, but there's never too much.

    The side of the house with my lounge/diner and second bedroom are entirely unaffected.

    Insulation is not up close to the eaves so there's sufficient airflow around the loft space. In fact, it's very airy up there and you can feel a breeze when you're in there. It doesn't feel stale up there and every person who's been up has commented on the quality of airflow.

    I have a combi boiler installed in a cupboard downstairs and the flue seems absolutely fine with how it's installed up into the loft, and is on the opposite side of the roof to where I have the problem.

    I don't dry clothes indoors and use a tumble dryer in the garage, that vents outdoors.

    Loft hatch seems to be sufficiently insulated etc. Levels of insulation in loft seem fine and nobody has commented otherwise.

    So. I've had three roofers out so far and they all have differing opinions and ideas on what needs doing, from solely installing vented ridge tiles, to replacing the felt on the problem side, to a complete new reroof.

    The chap who has recommended the vented ridge tiles spent the most time inspecting the roof and loft of anyone who came out. He was initially concerned that the battens and felt would be damaged due to how much water was gathering on the inside. But he took several tiles off and inspected from the outside, but found the felt and battens to be in good condition. However, frustratingly, he stopped short of guaranteeing the vented ridge tiles would solve the problem as he agreed there was already a good amount of airflow in the loft. He said an alternative would be to refelt the entire affected side, which should solve it, as it'd be far more breathable than the old style felt I currently have.

    As with everybody, money is a consideration e.g., I have very little haha. If the work needs to be done, I'll get it done, but I don't want to unnecessarily spend especially if there's a potential fix concerning the way I'm living. But at the moment my concern is the insulation becoming saturated and causing further stains on the ceiling, the beams becoming saturated and going to rot etc.

    Also. A couple of questions:

    Is there a dehumidifier or air circulation device tailored for such situations that could just sit in the loft space and vent air/moisture directly out?

    I currently turn my heating off at night and switch it back on when I wake up in the morning. Obviously the temperature of my home is then going from about 20 degrees in the day to half this at night and takes a good few hours to heat back up again in the morning. Would I be better leaving the hearing to run all night in an effort to stop the coldest rooms from getting too cold, since the condensation seems to be above these rooms? Not sure if this would have an impact or not, but it's curious that the issue is mainly above the two coldest rooms that never seem to sufficiently warm up.

    What does everyone think? Any advice is gladly received as I'm a hugely anxious individual and this is doing nothing for my inner chi
     
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  3. KanielDemp

    KanielDemp

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  4. JohnD

    JohnD

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    @KanielDemp

    have you got holes in the ceilings, for example for downlighters?

    an extractor fan is better than an open window, because it sucks steam out of the room. depending on wind direction, a window can blow it into the house. please explain why you think your extractors are wrong.

    what is that white thing near the back edge in your last pic?

    show us a closer photo, with the insulation pulled back please.

    What is the thickness of your loft insulation?

    Are the old tanks and pipes still in the loft?

    If your house is slow to heat in the mornings, you could turn down the stat to 12 or 15 at night, rather than off, and close all internal doors.
     
    Last edited: 29 Nov 2021
  5. Harry Bloomfield

    Harry Bloomfield

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    As above - moisture you are producing in the bungalow, is making its way up into the loft. I would begin by adding a proper extract system in the kitchen - a properly installed cooker hood, venting outside. Insist lids are used on all vegetable boiling pans, which will release less moisture and save fuel. Likewise the bathroom. Open windows only help, if the windows are on the lee side, sucking moist air out.

    A dehumidifier will not help much placed in the loft, it will be too cold up there to work well, one downstairs though might help and make the house feel warmer. They do not vent outside, they just circulate air, collecting moisture from it. Some collect it in a tank, if you don't mind emptying the water collection tank often. Better is one which can have a small plastic pipe attached, so they constantly drain. I use one in our utility room, for frying clothes combined with a fan, it drains via a pipe into the dish washer drain stand pipe.

    Overnight internal temperatures falling to 1/2 of 20C (10C) suggests your insulation system is not working very well at all, if true. My heating is set to come on during the night, if the temperature inside falls below 16C - it never gets that cold as to ever fire the heating up, even with sub-zero temperatures outside, as now.

    If none of that works, you might consider adding an extract fan in the loft, again of the lee side of the bungalow.
     
  6. KanielDemp

    KanielDemp

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    Hi both

    Thank you for your responses. I'll do my best to answer your questions, although some further investigation next time I'm up there may be required.

    I've got no holes in the ceilings for downlighters or anything else.

    I've had a couple of roofers up there this year to inspect at various points and they said the bathroom fan's trunking was not well fitted and needed looking at, as well as needing an improved unit. I just stopped using it altogether and the condensation was reduced, although not fully stopped. The white thing you can see in the photo is the bathroom extractor fan pipe. As for the kitchen one, I must admit, I am modern man and rarely actually cook and certainly it's rare that I boil anything, so the window usually suffices haha.

    I'm not sure on the loft insulation thickness. I'd need to check, all I know is it's doubled up. When you say to pull it back, where abouts do you mean?

    There's no old piping or tanks up there, I believe the property has always had a combi boiler of some description and it's always existed in the downstairs cupboard. The only piping in the loft is in relation to this unit.

    Yes, it does drop some warmth overnight. The property is graded EPC grade C/70, so isn't bad by any means, but the boiler regularly fired up to maintain the desired heat. The controls are only set to the default temperature though on the boiler itself, so the temperature of the radiators never gets searingly hot to touch.

    I have overstated things by saying it drops by half. But last night I turned off the heating at around 8pm and when I put it back on at 4am it was at 14 degrees.

    I'll consider the advice on the dehumidifier and consider that as an option for sure.

    Thanks both.
     
  7. JohnD

    JohnD

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    the insulation is either scattered or rolled onto the ceiling below. it will pull back so you can look at the extractor hose.

    also, in daylight, with the insulation pulled back, please photograph the eaves. is there a gap you can see daylight through? how big?
     
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  9. Old Salt

    Old Salt

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    You can get roof vent tiles, that fit in place of the roof tiles rather than the ridge, that will give greater airflow in the loft. When I moved into my bungalow the loft was really stuffy with a leaking roof and tears in the felt.
    Roofer removed damaged tiles, slid in new felt to overlap the torn felt, fitted 4 roof vent tiles and replaced 12 cracked tiles. £500 quid all in.
    Having been on the roof it was worth it to save me going up there, but proper vent tiles will be far better than your slide in the felt vents.
     
  10. JP_

    JP_

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    Check for leaking extractor fan vents. I had this in an extension - there was no ventilation in the "breathable" roof felt, and the kitchen extractor was leaking into the loft.
    Sealed the pipes and added loads of flap vents, and all OK now.
     
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  11. KanielDemp

    KanielDemp

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    Thanks all. I appreciate the advice and will have a look at getting some more photos next time I can get up there. May not be today or tomorrow as out about.

    I'll see about some ordinary vented roof tiles in addition to the ridge ones.

    One question. As stated, I haven't used the extractors in either kitchen or bathroom for the best part of a year and always vent via the window. Even when not in use, could moisture be escaping up through the extractor fittings/devices and into the roofspace if not fitted correctly?

    Thank you.
     
  12. Harry Bloomfield

    Harry Bloomfield

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    Properly sorting that out, ought to be at the very top of your list.
     
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  13. Why Not Indeed

    Why Not Indeed

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    If there's no mechanism to stop air flow when the fan isn't on:
    - If the vent is near the top of the room, warm air will rise up it into your roof space
    - If there is a breeze then it could be pulling air up it into the roof space
     
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