Condensation on breathable membrane

[Richards303]

Hi
I have had new breathable membrane fitted a couple of weeks ago. It's Tyvek Supro. Fitted under battens on a sloping roof, redland tiles, 1910 terraced house.
Problem is there is condensation forming on the membrane. Mainly down by the eaves and behind a loft room where there is 50mm gap around for airflow.
The roofer and I were expecting the membrane to have very little condensation as breathable and Tyvek states no ventilation is required. That said over fascia vents have been fitted but haven't helped.
There is old 100mm between the ceiling joist but a lot of air can get into the loft space from rooms below which I know isn't helping.
Our next possible move was to try cutting the membrane under the dry ridges to see if this helps with air circulation and ventilation but Tyvek recommends lapping the membrane over the ridge underneath. I have also tried putting in the plastic lap vents but there's condensation directly above them so that clearly hasn't worked.
I'm at a loss of what to do next

Thanks

 

[Richards303]

I should add that the condensation was there this morning and it's not particularly cold. There was a colder last week and the condensation was worse in the morning but it did mostly clear by the end of the day when the temperature outside rose a bit

 

[JohnD]

... a lot of air can get into the loft space from rooms below which I know isn't helping....

CONDENSATION IN LOFT (ANSWERS)

This seems to be the time of year for condensation in lofts, so instead of replying to lots of queries I though I would write this "one-size-fits-all" post. Please also see //www.diynot.com/wiki/Building%3ACondensation-in-Houses Condensation in lofts occurs when the amount of water...

www.diynot.com

 

[Richards303]

Thanks. I did read this before but it didn't really answer my question in regards to why breathable membrane isn't doing its job and why the ventilation added hasn't had any effect.

I should have also added the the Tyvek replaced old bitumen felt with lap vents and there was no real issue with condensation on that.