08/05/2026
🚨 ANSWER 🚨
The top of the roof is often left open under the ridge on purpose for ventilation.
On modern roofs, the breathable membrane/felt is usually stopped short at the apex to allow airflow from one side of the loft to the other. This helps reduce condensation, damp, mould, and timber rot in the roof space.
Then the ridge system above it, whether dry ridge or mortar bedded ridge, keeps the rain out while still allowing the roof to breathe.
If the felt is completely overlapped tightly over the top with no ventilation elsewhere, you can end up trapping moisture in the loft.
A lot of homeowners see daylight under the ridge and think it’s wrong, but a small gap is normally completely standard 👍
