Insulating a ground floor flat

[matt26]

Hi all

I am renovating a ground floor flat (1990s), which for most of the time does not have any occupants above. I've read that it's common not to insulate between flats because people generally keep the heating at similar levels and the temperature difference means it's not worth it, but for us it's usually a cold empty flat above. Our ceilings have around 100mm void above the plasterboard, and a concrete floor above that. Does anyone have any advice on what to do with insulation here? The flats are electric only heating, so bills are quite high. Is it worth ripping down the plasterboard and filling the void with insulation? Any particular types? Any problems with ventilation if we do?
Thanks for any input!

 

[motorbiking]

You probably don't have a right to the space above your ceiling, so might be breaching the lease if you did. A flat built in the 1990s will likely have a U value of around 0.45. That is pretty good. If you are really keen on the idea, then you could board the ceiling with celotex and add new plasterboard, essentially lowering your ceiling by 40-50mm. It's unlikely to be worth it (cost around £1000 allowing for decorating, depending on the size). Do you have thick curtains covering the windows?

 

[^woody^]

You probably don't have a right to the space above your ceiling,

The space that the flat owners electrics and other services are in?

 

[^woody^]

PIR (foil backed foam) insulation board is the most efficient being almost twice as efficient as quilt type. But it's more difficult to install, and will need good detailing to maintain the fire protection of the floor/ceiling - PIR was used at Grenfell.

Rockwool will give additional sound insulation.

 

[motorbiking]

The space that the flat owners electrics and other services are in?

Likely to be lease, so he owns nothing more than a right to occupy the dwelling for the number of years etc.

Obligation is usually not to alter or modify.

I own a flat where my water tank is in the roof space. I have a hatch giving me access. Technically I'm not allowed to occupy it as part of my lease.

 

[^woody^]

Likely to be lease, so he owns nothing more than a right to occupy the dwelling for the number of years etc.

Obligation is usually not to alter or modify.

I own a flat where my water tank is in the roof space. I have a hatch giving me access. Technically I'm not allowed to occupy it as part of my lease.

It will depend on what is specifically demised and stated in the lease. Unless expressly excluded, the OP would have the right to use the air void in a ceiling - use it for services normally, but could use it to fill it with insulation.

 

[matt26]

PIR (foil backed foam) insulation board is the most efficient being almost twice as efficient as quilt type. But it's more difficult to install, and will need good detailing to maintain the fire protection of the floor/ceiling - PIR was used at Grenfell.

Rockwool will give additional sound insulation.

Thanks, I’d like as much benefit as possible if we’re ripping the ceiling down so maybe PIR is the way to go.

Obligation is usually not to alter or modify.

I’m allowed to modify. I’m already taking out a stud wall to change the layout, so thinking now is the best time to insulate the ceiling (if it’s worth the hassle)