Condensation on roof sheets (pic attached)

[Sandrine1982]

Hello.

I've just been to the eaves storage in our loft room (after some time) and I'm shock to notice that all the roof sheets are wet with condensation!

Why on earth is this happening?

The roof is relatively new and I didn't notice anything like this last year when we moved in.

Could it be that we have too much stuff in there and the air can't circulate?

Or is it the floor underlay that I covered the floor with? I thought it would be good to stop the heat escaping from the room below.

I'm not sure what to do but I don't want to leave it like that as it might cause the joists to rot ...

any advice greatly appreciated...

TIA

Pic

Get a builder to install a couple of ventilation points in the roof otherwise you are right that it will cause rotting of the joists.

It shouldn't be too expensive and have just had the same done.

You are supposed to have vents in the soffits outside. However the air needs to flow, so nowadays most roofs have vents on the ridge or high up on the tiles. Have you obstructed the airflow from the soffits with the underlay?
If you stand in the loft on a breezy day, the draught should be quite evident.
You say loft room? So you built a room in the loft and now only have eaves storage?

I can't see it, but I expect you have insulation or flooring pushed into the eaves.

Pull it back so you can see daylight on at least two sides, allowing airflow inwards and outwards from outside.

This is necessary to ventilate out the water vapour/damp air.

You have too much heat from the house coming through the ceilings into the loft space which is causing it. You need to increase the insulation in the loft to stop this and then ventilate the roof space. This can be done by various methods, eaves vents , air bricks, ridge vents ….. a combination of these is a good idea to get a good airflow in the roof space. In a cold roof ( yours ) the roof space is supposed to be the same temperature as the outside , this will prevent any moisture/ condensation forming.

I have seen this before and the loft was covered in mould too, it had no ventilation and it was very humid in there, they also had mould on the ceilings in the house too 🙁.

Thanks everyone.

I will try to move the underlay so that there is more air coming in from the soffit area.

I might have actually covered it, not knowing what I was doing 🙈

Definitely needs more ventilation. The condensation has built up because the damp warm air has nowhere to go

I have this since a loft conversion. Vents haven't helped. It's a worry we might need to replace roof with a breathable membrane at some point.

Sorry to hear that @CottonSock . So annoying 😣

Yes @C4tastrophe and @PigletJohn .
there is a loft room room which is insulated. The insulation (PiR boards) is only on the back of the wall - if that makes sense. The floor in the eaves is just planks so I covered with some thermal / acoustic underlay which I had left from doing the floor in the bedroom.
We already had one winter in this house and didn't notice a problem, maybe it's just the underlay and all that other stuff we put there over time ...

I'll try and clear it tomorrow, and wipe it dry... hopefully it will help 🤞🏼🤞🏼🤞🏼🤞🏼

Are the boards nailed down? Ideally you’d insulate under the boards while leaving the air gap at the end for air to flow into the roof void/eaves.

Useful thread, thanks all. I've just been up I'm my loft to check. No condensation, so one less thing to worry about. I wouldn't have thought to check.

We had very gusty winds a few weeks ago and I heard a big crash in my loft. My trusted roofer has just been and said it needs venting, condensation dripping. This bungalow needs so much work doing!