Concrete hearth & ceiling insulation

[Joelc]

Hi all,

Bit of a mixed one here.

The old concrete hearth is quite soft and crumbly. Should I attempt to fill in the parts of the hearth where they are pitted, to smooth it off, some of it will be covered by the wooden frame I will be building round the chimney, but I'm not sure of I need to do anything else to it.

View media item 65351
Secondly, I plan on using the old fireplace hole to house all my AV kit, so obviously I need to protect from damp. The chimney will be capped next week, but from an internal point of view, should I dot and dab with foil backed plasterboard? I was going to use some marine ply or OSB for sealing the flue where it enters the fireplace at the top (ill be sticking a vent in somewhere as well)

Finally, we get a lot of noise from floorboards creaking etc next door, and in turn I also want to keep the noise levels from the home cinema down. While I have the ceiling down should I fill with rockwool or similar? Should I also fill the gaps between the bricks where the joists enter with foam, or cement?
View media item 65352
Thanks for the advice in advance.

 

[dann09]

A number of recent threads on the questions you raise can be researched on here.

On the upper right side of the c/breast brickwork is loose, and the T&G(?) boards above are not falling on a bearing/support where they meet.