condensation on chimmney breast

[CharlieB1981]

hi,

have a problem and wondering if anyone can help.

i have a 1920's semi detached with a fire place and chimney breast that has 2 flues, one for the downstairs fire one for the upstairs.

the chimney breast where the flue is for the downstairs fire has damp penetrating to the exposed internal wall and we cant figure out why.

its only on this half and not the half for the flue for the upstairs fire. the fire place is not blocked up and has a mushroom on the top to still allow air flow.

this was bad when i moved in and had stained through the plaster so i want to repair it before replacing this.

any thoughts on why or how to fix this.

many thanks

 

[big-all]

you do have an open vent at the bottom to allow airflow dont you

 

[JohnD]

is the flue used e.g. by a gas fire?

 

[foxhole]

Check flashing and pointing to chimney may be letting in rain which will descend to lower floors.As stated needs a vent to breast or there is no air flow.