Loft soaking wet from condensation - help!

mbailey

Exactly the same for me. Went up in the loft today to get the boxes down for the Christmas decorations (probably like all the others on this thread) and saw the same thing. Lots of condensation on the felt dripping down onto the loft floor.

All of my things are in plastic boxes with sealed lids so nothing is ruined, but I am a little worried about what the water will do. The part of the loft that has a wooden flooring just had small puddles of water on, but the parts that I haven't boarded I can't see, but I can only assume the water is soaking through them.

I already have a vent at the top of the roof (which I assume is the ridge vent).

Is it that the houses in the UK aren't designed with his cold weather? I wonder how houses in other parts of the world where it is always colder are built?

EDIT: I meant to say that the cold water tank in the loft is lagged around the sides and top, but the central heating expansion tank has no lagging and no lid. Could this be causing the problem?

Porky996T

I should have been more specific and stated a continuous vented ridge system...this is the type of thing...

Marley/Eternit vented ridge system

Houses in the UK are designed for cold weather, it is that the science of building is getting more and more advanced and is developing all the time. For example a house built twenty years ago will not have the same thermal efficiency as one built today, and contrary to the general opinion, houses built today are of a much better standard than those built 10, 20 30 years ago. Just as a point to indicate that materials science has progressed - on every house I have designed, I never put vented eaves or ridge; instead I use a breathable roofing membrane (felt) and the moisture vapour just passes through without the water penetrating from under the tiles. Gets rid of the need for vents - if vents are not there, you cannot block 'em

Mikeyorks

isofa wrote: »

I don't think the soffit vents are enough on our roof, there are only a handful of circular ones, I think a continous grill run would be better, I'm sure before they were replaced with uPVC that is how they were setup.

Exactly the same problem in a '70s bungalow we moved into 4 years ago. The stains on the roof timbers show it's been a problem for a while .... but I'm a regular visitor to the loft and it's really only since early Dec I've ever noticed 'proper drips' on the part boarding. And, significantly, it's only on the 50% of the loft where I've increased the depth of insulation! (Yes - I do intend to do the other 50% but the itching from the first section persuaded me to postpone it until Spring!)

I think we exacerbated the problem having the soffits / facias replaced last year .... in order to keep the fieldmice out of the loft. There are circular vents the installers added after the fit. But they're clearly inadequate, and I'd already made a mental note to double the quantity by fitting them to the soffits under the bargeboards - where they get more air.

(A few years ago we had a huge wasps nest, I assume they got in via the soffit vents!)

Also came back from a holiday, late last year, to be surrounded by irate wasps as I was putting the suitcases into the loft. Traced their entry / exit to the small gap where the roof tiles interlink .... I think you'll find the mesh size on the soffit vents tends to deter entry? Both of wasps ..... and, it appears, fresh air!

sidefx

http://forums.moneysavingexpert.com/showthread.html?t=1323599

some info on this thread may help:D

The_Governor

Any tips on what to treat the timber with in the loft DIY style to help protect from damp, just a temporary fix while we sort the environment out?

brig001

For condensation to form, moisture must be getting in somehow. mbailey, yes the tank should have a tightly fitting lid. I guess a piece of tinfoil over the top, scrunched around the edges to make it almost airtight would help for now. Make it dip in the middle so that drips would fall back into the tank and not towards the edge.

All rooms should be sealed from the loft, especially bathrooms. I used mastic around where cables penetrate the ceilings for lighting and this helped.

The_Governor

Tell you what, I just nipped up to have a scout and it seems a lot drier up there today, a lot less evidence of dripping on the loft boards.

I can't feel a whole lot of draft from the edges of the roof, I am wondering if when the blokes fitted our new soffits and fascias they've slowed the airflow, I don't think they removed the old wooden boards so the breeze has to get though two sets of vents now....

There is a slightly breeze today so it's less still than it has been previously...

We do have inset ceiling lights in the bathrooms, so we will be seeing heat rise up through those thinking about it...

isofa

Mike - good to know (!) we have exactly the same problem, I suspect the soffit vents are to blame too.

The Governor - again I agree re the soffit vent issue, these uPVC installers are potentially causing all sorts of problems, using the odd circular vent here and there, surely there should be one between each pair of rafters? I don't know how many rafters we have, but must be 20, and if there are only 5 vents the whole way alone.

PS there is no condensation above either of our bathrooms (one ensuite, one bathroom), one has downlighters, which are exposed for heat safety (although you can seal these with intumescent covers if you wanted too), all the condensation comes mainly on the area above rooms furthest away from those, but the part of the roof which gets the least sunlight in the winter.

When temperatures change drastically air in the loft can condense a little anyway, I think it's more to do with the lack of airflow and draft than any major issue of moisture rising. You'll find people who put more insulation down often see this problem too.

Leaving the loft hatch open is helping dry it out too, but makes the upstairs cold obviously!

Thanks for all the responses so far, and sorry to hear others are experiencing the same, the other thread makes good reading too, obviously a widespread problem. We had snow last night and today, it's freezing cold, no wind at all, and it's worse today, finally on the other side of the roof that never gets affected, I've had a summer oscillating fan running in there all day just to stir up the air, but obviously it needs better venting of some description.

I'm tempted to get the soffits replaced with ones with far more vent slots all around as a starting point, although our uPVCs ones are only 8 years old, so it's hardly money saving!

Else for quicker action some vented tiles / breathable felt (sounds major though)

The_Governor

My plan is to wait for a windier day and get up to see if I can see any airflow... thinking about it, going up with a candle would work too, as long as I don't set the roof on fire

isofa

The_Governor wrote: »

My plan is to wait for a windier day and get up to see if I can see any airflow... thinking about it, going up with a candle would work too, as long as I don't set the roof on fire

LOL yes, I'd be careful with that, perhaps a few sheets of tissue paper would be safer