New ceiling for ground floor living room - should we be insulating above it?

[WhatKatyDidnt]

Edwardian house. The badly cracked lath and plaster ceiling in the living room is coming down and two layers of plasterboard are going up. Should we also be insulating above the plasterboard or will two layers provide the same heat / sound insulation as the old ceiling? Thanks!

is there a heated room above it? Or a cold roof?

To muffle sound, you can put dense mineral wool batts tightly between the joists. They are heavier than loft insulation, and this extra mass helps muffle noise. It is especially important to pack the edges and corners tightly, as noise will get through the weakest point.

Electric cables should be above (or below) the insulation, not surrounded by it. Cables for lighting circuits are not of great concern, as the loading is so low.

If you have downlighters (I hope not) you can buy or make boxes or hoods to prevent the insulation flopping onto them and causing overheating.

PigletJohn, thank you! Yes, there is a heated room above (a bedroom). No downlighters just a pendant in the centre. Do you think that without the wool batts the noise would be quite bad?

Old lime l&p ceilings are thich and heavy, and, except for the cracks, block more sound than most. Two layers of plasterboard plus a skim will be good for noise, but the dense batts will also help.

As it is a heated room above you needn't worry about heat insulation.

Thank you so much. Really helpful.