Finding Cause Of Damp

Your description of black mould indicates condensation and not an issue from the exterior . This could be made worse by an old repair to the interior where thick filler was used , this also causes a damp condition , called hygroscopic dampness . It’s unlikely to be anything from the outside.

If it’s not the gutter it could be a shortage in the length of the felt as the felt should reach the gutter Regards Chris

Where exactly is the damp/ mould If this has been cleaned off and re appearing and it's not your gutters it may be a cracked or broken roof tile. A lose lead flashing etc If this is not the problem then I would suggest having 2 x pacifier vents fitted in that room as these allow constant airflow and are not electric. They are through the wall vents but have a baffle inside which stops any outside noise or cold draughts. Hope this helps

Yes, it's sounds like condensation. Moisture condenses on the coldest part of the room. Usually outside walls. If it's high up as you suggest, the lift insulation is probably missing at eaves level which is correct to allow the roof timbers ventilation. However, this makes that part of the ceiling the coldest and more susceptible to condensation. Introduce ventilation into the room. Leave windows open or locked on vent. Introduce a dehumidifier. Reduce moisture by not drying clothes indoors and keeping bathroom doors closed after showering.bEven keeping lids on pans will help as moisture is carried around the property with air. In extreme cases, you could have the ceiling/walls covered with insulated plasterboard and skim med. This is a big job but sometimes is the best solution. Regards Paul