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Bad condensation problem in new roof space

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10 Jan 2025
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Following on from my previous thread about frost in my new roof space, a week on from that I seem to have a bad condensation problem in my loft. New roof went on last month with 3 ply breathable membrane, and ventilation at eaves and ridge. We also had the insulation topped up in the roof space to comply with building regs.

When I put my head in the loft hatch it feels cold and I can feel air moving but I still seem to have a condensation problem. Insulation isn’t pushed into the eaves, only goes across to the rafter roll vent in the photo. I never noticed this issue in my old roof space or maybe the older felt didn’t show the condensation as much and I wasn’t checking it every winter (only been in the house 3 years). Nearly all the condensation is near the bottom at eaves level. It goes across the whole length of the roof.

I’ve put draught excluder tape around the loft hatch but it’s not insulated. I’m not sure what else I can do myself.

Do I get my roofer back in to deal with this? Or will the condensation naturally evaporate through the membrane and I need to be more patient. Any ideas gratefully received. Thanks
 

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No down lights or bathroom fan venting to loft?
I've also seen bathroom extractor pipe venting above soffit and not going out.
You can also add board around edges so insulation don't block off soffit air flow
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Yes there are down lights/spot lights in the bathroom and en-suite. I didn’t put them in and need someone to go into my loft to look into that. Also we have an extractor fan that doesn’t work in the bathroom. I have put duct tape over the open vent in the bathroom but I suppose moisture could still be getting through (we have the window open in the bathroom whenever it is used until it’s completely dry. I dry all clothes in the tumble dryer at this time of year including any towels after they’ve been used so they’re not adding any moisture to the bathroom.

I’ve had the dehumidifier in the bedroom where the loft hatch is on all day and it’s hardly collected any water (it’s a new Meaco one) and my humidity reader for upstairs is reading 45%.
 
No gable wall vent
I’ll have to look into getting one fitted. None of my neighbours have them but plenty have roof tile vents. I know at least a couple of the neighbouring houses have condensation issues.
 

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