condenstaion in loft

[rockinricko]

Hi all

So to cut a long story short, I just went round my dads as he has some of my stuff still in his loft, and he wanted somewhere to sit and do his huge 10000 piece puzzles and decided the loft would be perfect so tidied it up and started insulating between the roof joists. He's insulated the whole lot with fibreglass type stuff (but it's not itchy,) and has added a breathable membrane to part to hold it in place and was planning on finishing that and cladding it with pine just to tidy it up, but while getting my boxes found condensation has formed between the roof and insulation as I spotted some drips on the wooden floor, and when I pushed my hand through in places it felt quite wet.

He said his builder friend told him what to do, but I know nothing of building stuff, but kind of thought that didn't seem right. It's not heated, he just goes up there and leaves the loft hatch open and that warms it up enough for him, but he says he hasn't been up there for a month or so.

The only other thing up there other than a few boxes is the water tank and there is like a hole in the ceiling above the boiler which you can just feel warm air rising which is apparently to stop the water tanks getting to cold.

I have no idea about these things, but wondered as one of the water tanks is open, should these have lids on them, and is the condensation only because it's partly finished and he hasn't finished putting up the rest of the breathable membrane yet.

I know it's a long shot, but he doesn't seem worried, but it didn't seem right to me.

Rich

 

[freddiemercurystwin]

Unless he ventilates the space between the insulation and the felt (assuming he has it) it will be a condensation trap forever and a day. Short term it won't a problem, long term mould will set in and eventually any damp timber will rot. The breathable membrane is not adding anything advantageous in-fact it is just allowing warm air to pass into the insulation where it condenses as it reaches the outside.

 

[rockinricko]

Hi

Thanks, this will sound bad of me, but he's too old for it to reach the long term stage if you know what I mean. However would it help to fit a none breathable lining, or is that just going to make it worst?

Many thanks

Rich

 

[freddiemercurystwin]

Removing the breathable membrane will make little difference as its breathable! The bad thing is fitting the insulation at rafter level and not being able to vent the air gap (if there even is one) between the insulation and the felt behind the tiles assuming there is some.

When the condensation begins and eventually starts dripping on his puzzles he'll want to do something about it then assuming he lives that long you merciful barsteward!

 

[rockinricko]

many thanks for your help, its on hold for the mo as he is deciding what to do.