drying loft after bad condensation

[iamrcb]

Due to the cold snap there's a huge amount of condensed water on the roofing felt in my loft. I thought that I had solved this problem earlier this year after installing 6 roof vents, It seemed to clear up the condensation very quickly, but it seems that it is still a problem.

I've laid another layer of insulation today (leaving a good gap near the eaves) and insulated the loft hatch, these should help

The felt is still very wet so should I:

a) leave it, it'll go on its own accord
b) or sponge/wipe it all off, which creates an alarming amount of drips an water on top of the insulation.

If in doubt, always consult pistonheads!

Thanks

[GreenV8S]

Have you got a central heating header tank in the loft?

[iamrcb]

No header tank.

What about hiring a dehumidifier?

The condensation is very bad on the rear roof pitch and there's hardly any on the front, I assume that's because it gets the sun.

Edited by iamrcb on Sunday 7th December 18:12

[singlecoil]

I bought a dessicant dehumidifier from B&Q recently. Brilliant machine. The advantage over compressor based dehumidifiers is that they work well at low temperatures. Get one up there for a while, and dry it out.

[jeff m]

To avoid condensation in an attic the temp inside should be closer to external temps. It's the higher internal temps that are causing it.

Air flow.....You have ventilation in the eaves but probably nothing higher.
Cooler air cannot enter if the warmer air cannot escape.

A turbo type vent near the ridge will solve this or even a vent high up will do a decent job.

Edited to remove tank comment 'cos I don't read too well

Edited by jeff m on Sunday 7th December 18:40

[iamrcb]

Thanks.

I'll get a desiccant dehumidifer. Even after drying out the loft this time it'll be a useful machine

http://www.cnmonline.co.uk/8L-day-Desiccant-Dehumi...

Edited by iamrcb on Sunday 7th December 18:43

[iamrcb]

jeff m said:

To avoid condensation in an attic the temp inside should be closer to external temps. It's the higher internal temps that are causing it.

Air flow.....You have ventilation in the eaves but probably nothing higher.
Cooler air cannot enter if the warmer air cannot escape.

A turbo type vent near the ridge will solve this or even a vent high up will do a decent job.

Edited to remove tank comment 'cos I don't read too well

Edited by jeff m on Sunday 7th December 18:40

Thanks. I'll keep an eye on it then i'll look into getting some ridge vents installed.

[jeff m]

iamrcb said:

jeff m said:

To avoid condensation in an attic the temp inside should be closer to external temps. It's the higher internal temps that are causing it.

Air flow.....You have ventilation in the eaves but probably nothing higher.
Cooler air cannot enter if the warmer air cannot escape.

A turbo type vent near the ridge will solve this or even a vent high up will do a decent job.

Edited to remove tank comment 'cos I don't read too well

Edited by jeff m on Sunday 7th December 18:40

Thanks. I'll keep an eye on it then i'll look into getting some ridge vents installed.

Just checked your profile...
You shouldn't be posting this
UK type construction and roofing in particular make the instalation quite costly, whereas in the US it is very easy to put in a high upper vent and not terribly difficult to install a turbo type near the ridge. Although I wouldn't like to do either today.....a bit chilly.
I would buy two dess packs and rotate them.

[iamrcb]

jeff m said:

iamrcb said:

jeff m said:

To avoid condensation in an attic the temp inside should be closer to external temps. It's the higher internal temps that are causing it.

Air flow.....You have ventilation in the eaves but probably nothing higher.
Cooler air cannot enter if the warmer air cannot escape.

A turbo type vent near the ridge will solve this or even a vent high up will do a decent job.

Edited to remove tank comment 'cos I don't read too well

Edited by jeff m on Sunday 7th December 18:40

Thanks. I'll keep an eye on it then i'll look into getting some ridge vents installed.

Just checked your profile...
You shouldn't be posting this
UK type construction and roofing in particular make the instalation quite costly, whereas in the US it is very easy to put in a high upper vent and not terribly difficult to install a turbo type near the ridge. Although I wouldn't like to do either today.....a bit chilly.
I would buy two dess packs and rotate them.

nice one. I'm more involved with earthworks, highways, st pipes etc. Blame the architect for above ground stuff! Its an old solid stone wall house which is often a pain in the arse.

[Busamav]

jeff m said:

Air flow.....You have ventilation in the eaves but probably nothing higher.
Cooler air cannot enter if the warmer air cannot escape.

this man speak much truth

[Simpo Two]

singlecoil said:

I bought a dessicant dehumidifier

Special Medal from the Spelling Police for being able to spell dessicant

iamrcb said:

I'll get a desiccant dehumidifer.

Doh!