Daughter has just gone into loft and it is extremely damp with water on the insulation. My first thought is that it is condensation caused by lack of ventilation, but I would like to hear what the team think.
Thanks John
Central heating pump dumping hot water into the header tank in the loft? Pump running too fast or water overheating.
blocked vents too mebbe
Warm moist air from the house leaking up into loft & condensation forming on the colder surfaces up there.
Venting the roof space should cure the problem, with vent ridge or vent tiles at the top of the roof.
Or maybe just pulling back the insulation from the eaves - it may be blocking pre-existing ventilation.
Everything everywhere is dripping wet ATM. Even the insides of cars that haven't been sat in for days. Probably not a good time to take far reaching decisions?
Thanks for all the input, the CH system seemed favourite at first, but tank is cold. It sounds as if insulation has been fitted up to the eaves, so preventing airflow, so Son in Law has rolled some back to assist in ventilation and we will see how we go. Thanks again,
John
Same here. We had a freezing cold night followed by a bright sunny morning yesterday and the metal roof of my garage/workshop was dripping water inside everywhere in torrents. I had to move a few damageable things somewhere safer before they got soaked. Normally it's pretty dry in there when it's either always warm (summer) or always cold (winter) but at the moment it's just at that changeover point where condensation builds up overnight. It was below freezing last night and the inside of the roof is now covered with ice this morning. No doubt that'll all melt off and drip everywhere later on. Spray on foam would probably sort it out but it's horrible messy stuff and I'm not sure I want to go that route.
Warm moist air from the house finding it's way up there and condensing.
+Insufficient ventilation.Roof leak.
If the loft floor is well insulated, conditions in the loft itself will be the same as outdoors i.e. dripping with water
Respectfully I disagree Stuart - my shed is humid, but generally dry inside - certainly not running with condensation.
A cold loft with adequate ventilation should remain dry even if the humidity matches outside.
I think the OP is wise to investigate this.
which is why wooden sheds are best. Metal ones are very different
Maybe. Interesting that there was no condensation on our bedroom windows this morning. First time for a week or so
It's worth, I think, thinking about ventilation timescales here. How long does it take for an "adequately ventilated" loft to exchange and/or equalize the air with the outside? It might, for example, be 6 hours or so for exchange, but take a lesser time to equalizing the temperature.
So one day is less cold and humid, maybe raining; the loft air is therefore also humid, but the water in the air isn't going to condense out because humidity and temperature are matched.
That night the skies clear, wind drops, and temperature falls by five degrees or so. By dawn, all the loft air has cooled to the outside temperature, but has only partially exchanged with outside.
The loft air therefore is too cold to retain all its water; and that excess condenses out inside the loft.
All that is needed here is for temperatures to equalise faster than the air (and it's water/humidity) is exchanged through ventilation.
I'm not claiming this is common, or the case under discussion here -- just proposing a mechanism.
#Paul
Don't be surprised if nothing changes quickly - it's been 100% relative humidity outdoors for weeks (just dipping a little for 2-3 hours around midday), and that's not condusive to drying anything out.
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