Black patch on ceiling

fig mclough

Just wondering what is causing a black patch one foot by approx 2 foot in the corner of a room and its starting to spread the whole way down the room. I'm sure the roof isn't leaking and i done the pvc facia and soffit myself so I know its watertight. The room is vented by a vent 3 inches by 8 just wondering would it be condensation and would the room need a bigger vent or neone have ne ideas. (Corner with condensation is on extior wall at gable end of house)

PirateShampoo

Sounds like mould, if you can check above it. It sounds like u either have a leak or a cold spot causing mould to grow when the warm air of ur room hits the cold spot.

fig mclough

pretty sure its not a leak as the plasterboard and dat feels dry what would cause a cold spot

PirateShampoo

Could be a draft getting in above the plaster board, had it in mine where the builders missed a section of insulation out.

Poke a screw driver through the patch and c if a breeze come out the hole. Also if its a leak the chalk in the board will be mushy.

fig mclough

cheers pirate shampoo id imagine thats what it is as there is no insulation at eaves and d cold air is prob circulatin through the air vents in the soffit and onto the plasterboard wud i be correct?

PirateShampoo

Yup.

fig mclough

Not sure what way roof should be insulated what I was thinkin of doin was gettin the yellow roll out insulation and stuffin the eaves but this would be stoppin airflow which wud lead to more problems.What needs to be insulated should I leave 1 space free at eaves so there will be airflow?(House is bungalow)

PirateShampoo

If its yellow fiber glass then dont worry about it blocking the eaves. Air will still pass through it even if u stuff it fairly solid. It should solve your problem.