Ventilating a bricked up fireplace ?

jhe

Any advice please incase I make a big mistake
I am about to get my living room chimney breast bricked up
asked 3 builders about ventilating and got 3 different replies, 
one says cap the chimney pots  and brick up the fireplace no vents needed.

Another says vent the chimney pots and air vent in the bricked up chimney breast but will this cause a draught in the room? 

Third builder say cap chimney but vent and vent through  the living room hearth  into the subfloor  which I guess will not cause any draughts in the living room

TheNorthStar

You should keep a through draft. Using the subfloor might work, though I’m not sure how you’d manage it around the fireplace, as the base is likely to be solid. In our last house, which had an open but unused fireplace, we capped the chimney at the top to keep the rain out while still allowing ventilation, and then added a small vent in the living room. The draft was never an issue, 

dickibobboy

I have 2 separate ones that were blocked up both with ventilation caps at the top. 

1 room just with a small vent at the bottom. 

1 room (living room) I vented into the subfloor which in turn is ventilated into the cellar, if i put my ear to the 40mm pipe that was used i can feel the airflow - 7 years on still no issues.