Strange damp patch above double doors during dry spell Damp can be a major issue in the home. Find answers to questions or post your own here.

[edvardo954]

I wonder if someone could help me with a recent issue with dark marks appearing above our double doors during this dry spell.
See below.

The doorway leads from our lounge to the conservatory. This issue has never been apparent until recently. I have been on the roof and replaced a broken roof tile which I thought would solve the issue. I have also extended the overhang of the tiles into the gutter. However the conservatory roof is very well covered with a rubber roof which also steps up behind the gutter.

The marks become visible in the afternoon after the sun has been on the conservatory roof all morning. The marks then disappear after 2-3 hours.

Any ideas what the root cause could be?

[stoneyboy]

Hi edvardo954,
Assuming you have no cross ventilation of the roof space and you have a steel lintel over the opening, the most likely cause is condensation.
Regards S