Alarm bell ringing

[Longshanks]

Hi

Just put some Christmas presents in loft. Noticed droplets of water on some areas of the felt sheeting and the loft itself.

We’ve had a lot of rain, but so has just about everyone else. Tiles look ok , but worried this is going to be big and expensive job now just before Christmas.

Can provide pictures but initial thoughts would be much appreciated.

Thanks for your time.

 

[datarebal]

Probably condensation, This time of year we get call after call..
Insulate the loft and not forgetting loft hatch. Ventilate above the insulation.

Post a picture or two anyway to be sure

 

[Longshanks]

Thanks. Will post photos when I get home. Reinstated the loft insulation a year ago, so wonder if that may have contributed to problem. Can you explain “ventilate above insulation”.

Cheers

 

[datarebal]

You need to keep the warm air inside the rooms not in the loft. So be sure it is insulated properly.
Also be careful the reinstated insulation is not blocking any ventilation routes that may have been installed originally. You need air flow in the loft space. This maybe by vent tiles or slates, soffit and high level vents.

Lets see the pictures and then we will know what is there.

Check the post by Mmcgar below A classic condensation picture

 

[Longshanks]

Photos now attached. I’m a bit more worried now, as felt on one slope is v wet, not just droplets! It’s the slope at back of house. (north facing) You will see that I haven’t boarded whole loft, using loft stilts to keep gap above insulation. I’ve checked and there is a gap if a few inches between insulation and boards.

I may have fitted loft roll too close to eaves so will check that tomorrow. Does the fact that water only on the one side imply more like a leak than condensation?

Grateful as ever for your advice.

 

[Longshanks]

Photos now attached. I’m a bit more worried now, as felt on one slope is v wet, not just droplets! It’s the slope at back of house. (north facing) You will see that I haven’t boarded whole loft, using loft stilts to keep gap above insulation. I’ve checked and there is a gap if a few inches between insulation and boards.

I may have fitted loft roll too close to eaves so will check that tomorrow. Does the fact that water only on the one side imply more like a leak than condensation?

Grateful as ever for your advice.

 

[JohnD]

have you got holes in the ceilings, for example for downlighters or pipes?

Is the loft hatch a close fit?

Are any water tanks warm or unlidded?

Does the bathroom have an effective extractor fan (that's used)?

 

[datarebal]

Firstly its not a leak, you have a roof covered with bitumen based 1f felt its water proof.....
north elevation , its colder and its usually the case to see more condensation there.
It's an easy fix, so don't lose sleep over it .
Check the insulation again , it's important not to scrimp including the hatch cover.
Once thats up to speed. then look at increasing the airflow
Before you spend out on vent tiles you can do a test by sliding spacers in between the felt laps which I can see are easily reachable. off cuts of overflow pipe or similar are good
This will allow addition airflow in and out of the loft. I have seen this cure the problem. You can then fit vent tiles ..after Xmas

Check the post by Mmcgar below everything applies here

 

[JohnD]

also

https://www.diynot.com/diy/threads/condensation-in-loft-answers.160032/

 

[Longshanks]

Ok cheers. We certainly have a problem with hatch, as badly fitting with gap. Will look at fixes and post (Not sure I could find link to this)

Many thanks again.

 

[Longshanks]

Sorry can see link now. (Crossed in post)

 

[John D v2.0]

just to clarify the above posts, it's not the ceiling level insulation you need to improve, it's the airtightness. So as above blocking gaps around lights and hatches and pipes.

 

[Doggit]

It's more than likely that the felt has been pushed right down into the eaves, and that's cut off the airflow into the loft. You're never going to achieve 100% air tightness from the house into the loft, and a certain amount of warm air with moisture will always get up there. Fresh air would normally come in from one side of the eaves, and flow out of the other, but most people tend to push the insulation down into the eaves to stop cold air getting in, and then get the condensation forming on the felt. But you could get a couple of ridge vents put in if you want to get rid of condensation without getting serious drafts in the loft.

 

[Longshanks]

Many thanks again. Will implement the suggestions and report back. I suppose the thing that bugs me is that, despite humidity getting in, the one pitch (South facing) is bone dry. Appreciate comments about this being common, colder, more problematic etc.

 

[Doggit]

Ah, but in someways, that proves what we're saying. If it was a leak, you'd have a trail of water running down from several points. But as the south facing (warm side) is dry, and the north facing (colder) side has the droplets, this tells you it's a condensation issue. It now becomes a case of how you ventilate the roof to overcome it, and reduce the condensations that's seeping into the loft.

Best of luck, and come back with your solutions.