Loft condensation

[nod]

Just had a call from our daughter 

Roof is leaking 

She’s recently moved into a two year old RedRow home 

From the photos it looks like pretty bad condensation 

She has inset solar panels on the opposite side of the roof 

All was dry up there when I fitted an Ariel 6 weeks ago 

Like most we’ve had freezing temps and a Flurry of snow this afternoon 

 

Im going up there tomorrow 

But the reason for posting is could it be anything to do with the solar

Its so difficult to tell from photos 

But any input would help 

[tonyshouse]

Don’t panic, does it dry out again during the following day? I think yes. 
 

I dint like it dripping on the solar inverter, fix something above it to divert the drips and may as well protect the ply boards and switch too. 

 

to eliminate solar, is it happening on both sides of the roof? 
 

Are they leaving the loft trap ajar? 
 

 

[tonyshouse]

Massive bonus points for uncluttered loft

[AliG]

There are many different roof build ups, but I am used to seeing sarking boards with gaps to let moisture out of the roof.

 

Is there any ventilation in the roof space? Or a VCL layer below it?

Edited January 2, 2021 by AliG

[nod]

5 minutes ago, tonyshouse said:

Massive bonus points for uncluttered loft

Ha ha 

 

 

It’s not happening on both side 

The hatch was my first thought 

I’ve asked her if it is warm up there 

Her reply was Freezing 

While I’m a builder she’s an accountant So warm air could be getting in

Id expect everything to be cold up there there 

Ive never seen condensation that bad in a loft before 

I will no better tomorrow 

[Mr Punter]

It is warm moist air getting in from the house.  Probably no vapourcheck at ceiling level and maybe holes for lights etc.  Is the top of the wall cavity closed off?  Often have plasterboard on dabs letting air in from below.

[nod]

7 minutes ago, Mr Punter said:

It is warm moist air getting in from the house.  Probably no vapourcheck at ceiling level and maybe holes for lights etc.  Is the top of the wall cavity closed off?  Often have plasterboard on dabs letting air in from below.

Good point also 

As I stated above the house is two years old 

The previous owner has boarded out the loft and will have certainly removed some of the insulation 

We put 500 mil down 

There certainly isn’t that

 

Thanks for the replies I will update this when I’ve had chance to look 

 

 

[nod]

13 minutes ago, AliG said:

There are many different roof build ups, but I am used to seeing sarking boards with gaps to let moisture out of the roof.

 

Is there any ventilation in the roof space?

I would suspect that there is adequate ventilation But you never no with mass produced housing 

I’m leaning towards the previous owners having the insulation striped out for the loft boarding 

Both where busy doctors So it’s unlikely they would have done of themselves 

[wozza]

We had exactly the same issue this time last year last year.

 

We had a few areas in the house where warm / moist air could enter the loft due to the work we were doing (soil pipe boxing in corner of house was open and goes straight into the loft), and we had a few downlights removed and a small gap / open section of ceiling in the temp kitchen on the first floor.

 

Once all of these areas were sealed the problem stopped and it hasn't happened again.

[tonyshouse]

Is it just under the solar panels? 

[MikeGrahamT21]

In theory the roof membrane should be breather membrane, however you could put some small wedges in the laps to increase ventilation. I suspect moisture is coming through the ceiling into the loft and the membrane simply can’t disperse it fast enough, so it simply condenses and then drips.

remember not all breather membrane is created equally, so try some methods such as the simple one I’ve suggested to increase airflow