opening bricked up chimney breast to make space for av stuff

[karigar]

hello please can anyone tell me the best way to open a chimney breast so that av equipment can be installed below a wall mounted lcd tv ,also what is the best way to seal the area to stop rain/debris falling on to the av storage area. There is only a single chimney on the roof but has to remian open as there is a gas fire connected to another chimney breast.

[thedoctor]

See our project on opening and closing a fireplace