Bad condensation (?) on underside of roof

[Mmcgar]

Hi all

I was just up in the loft there and noticed the underside of my roof is very wet, especially as you move away from centre. I've took a picture but not sure how much help it will be.

Does anybody have any idea what can cause this sort of thing or how big a fix it is? I guess it could be a number of things but just generally what would cause condensation on this

Thanks

 

[Notch7]

Warm air reaching loft space

Insufficient insulation at ceiling level

Roof ventilation blocked at eves level or elsewhere.

No lids on tanks

Extract duct from bathroom venting into loft

Generally some or all of the above.......

 

[Mmcgar]

Thanks for the reply.

It's the scale of the wetness that's concerning me, a little bit of condensation wouldn't bother me but the place is pretty wet, the insulation is wet from the dripping. There's no pooling of water but it's clearly been a very heavy drip.

In terms of insulation in the loft if anything there's too much, there's loads of it.

There's a cover on the water tank.

I think I've just panicked when I've seen the amount of water, I'm paranoid in looking at a whole new roof here!

 

[datarebal]

bad cases it can run... as notch says, insulate and ventilate.. extractor is worth a check

 

[JP_]

if its that wet I too would be looking at extractor fans.

 

[Mw Roofline]

Every Xmas we get calls about condensation in lofts as it’s usually the only time of year anyone goes up there.

 

[datarebal]

this is true...

 

[KenGMac]

Mmcgar, good evening.

Cold up here just now, but the temperature will drop further

What is happening is the moisture in the warm rooms below the loft are allowing the water vapour to get into the loft space, water vapour is OK in a warm space [the rooms of the house] BUT??? when the water vapour percolates into the [unheated] loft space it has to condense on the coldest surfaces.

Now in the loft space ??? as your were correctly advised, you have had a "load of insulation fitted" OK so far, BUT??

Some, possibly not all Loft Insulation installers actually know how to install such Insulation, that being there MUST be be ventilation of the loft space above the Insulation, this ventilation takes several forms,

1/. Circular vents in the soffit?? [the horizontal flat bit of the roof edge] or,
2/. Ventilated tiles on the roof surface itself??

Now, whilst the Insulation installer chucks in the Insulation they in 99.9% of these installations the installer does nothing at all whatsoever to address the potential for Condensation? [ they are not funded to do this function]

For more information have a look on this site for the "loft and Floor" section where there are a series of so called "Pinned posts" there is one post on there about condensation in lofts.

Ken.

 

[Mmcgar]

Thanks all for the replies. Especially Ken for providing that level of detail.

I'm not sure if there's any ventilation in the loft as is. Definitely no fans etc. I'm going to get someone out to have a look and increase ventilation if it's required.

Someone mentioned that "it can run " what does this mean? That the water can track to a particular point where it can pool?

Thanks again

 

[datarebal]

Gravity makes it run to a point where it drips off. Fans, we mean bathroom extractors not connected to the outside.
I can see you have interlocking tiles on the roof so you might try simply wedging open the laps in the felt with pieces of pipe or timber (gently)
This will allow natural ventilation into the loft, see if that helps. its a free tip.
And make sure the loft hatch is insulated

 

[Mmcgar]

Hi, I have had a roofer out and he has said the problem is that there is vents fitted to my roof but there has never been a cutout made to actually air to flow from the loft out the vents. He is going to make this cutout. I'll see if this solves the problem

 

[Mmcgar]

Here is an old picture of my roof which shows what I assume is the vents. I take it that the vents had been fitted but no cutout below then made

 

[datarebal]

Yes he is correct the idea is to cut the felt to allow flow. Have you checked the bathroom extractor?

 

[JP_]

I guess this is one advantage of my 90 year old roof - there's no felt, so air vents cover 100% of the roof!