Condensation question again, sorry!

[wedge69]

Hi,

I've read all the threads on condensation in lofts so I think I understand the reasons, causes, and the fixes, but just wanted to check that this is indeed condensation and nothing more sinister.

The wood that has the water droplets on is the underside of a lead valley. I remember looking in the summer in the loft and that piece of wood was dry, but had a layer of while mold that I wiped off, so this has possibly been happening for a while.

Also, am I right in thinking that the membrane you can see is the non-breathable stuff?

 

[ree]

OP,
Why not post pics of the valley - a long selfie stick batten can be used?
No need to get on the roof, you can pic from a ladder footed by someone.
First glance says the timberwork is wrong for a valley and the felt is definitely badly done.
I suspect water is getting under or around the lead valley.
FWIW: where are the cables coming from - are they comms cables?

 

[blup]

The lead gutter has developed a split through which water is seeping into tne wood below

 

[Koolpc]

The lead gutter has developed a split through which water is seeping into tne wood below

You have amazing eyesight to see that from behind your computer! Lol

 

[wedge69]

Thing is, I first saw it in a Friday, and it hadn't rained at all that day, which is why I thought condensation.

 

[blup]

Water pools on a flattish surface

 

[Alastairreid]

Also, am I right in thinking that the membrane you can see is the non-breathable stuff?

type 1f tar felt...correct non breathable.

insulate the underside of the lead valley which will help with condensation droplets forming.

 

[wedge69]

The things that was leading me more towards condensation were the fact that the droplets were very spread out (including the rest of the valley boards not shown in this photo), that it hadn't been raining the first time I saw it (though it was frosty) and that it is in the corner furthest from any ventilation.

I maybe being naive but I assumed a leak would be a bit more localised with more pooling.

 

[mrrusty]

If it's evenly distributed droplets, it's condensation. Warm humid air from below getting in the loft and condensing on the coldest surfaces. Just opening the loft hatch, lets a load in because warmer air rises. Loft insulation aids this by keeping the loft colder. By the sound of it, you know the remedies already.

 

[wedge69]

I think the fact I went into the loft on the Friday and let it in the warm air meant it was a lot worse when I went back in on the Sunday!

Again, I think the patterns of droplets on that picture suggest condensation?

It's tricky to know what to do. Due to the construction of the loft I've only got eaves vents down one side, and the valley is in the opposite corner, so I don't imagine there's much of a draught getting over there.

For now I'm going to try and manage the moisture level in the house and in the warmer months I'll make sure the hatch is properly sealed, and try and see what happens then.