Basement ceiling insulation

[LJD1974]

Hi,
I'm having the basement beneath my Victorian house developed professionally (underpinning/tanking etc), but am fitting it out myself and am not sure how to proceed with insulation between the basement ceiling and lounge floor above. It currently has brick air vents (although not sure if still required when all is finished as no vents between lounge and bedroom floors?).
The front to back lounge joists will be supported by a few side to side steel beams, so the new basement ceiling will be created by plaster boarding a dropped suspended steel frame. The immediate underside of the lounge floor boards (between the joists) will have 50mm rigid insulation and wet underfloor heating, so do I also need insulation immediately above the basement ceiling, along with existing brick air vents into the gap between the both?
Many thanks!

 

[JP_]

I think you probably do. Sounds like the space between the cellar ceiling and lounge floor is ventilated, and if lounge floor is insulated, then this void will get cold and draw all your heat away.
Depending on height of ceiling, i.e. how much space you can lose, I'd insulate with kingspan (or similar).

 

[LJD1974]

I think you probably do. Sounds like the space between the cellar ceiling and lounge floor is ventilated, and if lounge floor is insulated, then this void will get cold and draw all your heat away.
Depending on height of ceiling, i.e. how much space you can lose, I'd insulate with kingspan (or similar).

Ok. Thanks. Would the brick air vents still be required now that the space is becoming a gap between 2 useable floors?

 

[JP_]

I don't think so ... I would guess they are there just to provide ventilation to the cellar.

Do you have plans for some ventilation / extraction? Trickle vents in windows are needed to help replace air in homes now they are all insulated well - a cellar probably needs an equivalent of trickle vents or an extractor fan to stop the build up of moist, stale air. So before covering them up, work out if they can be used for that purpose - fitting a ceiling extractor fan on one might solve problems down the line.

Some advice here: https://www.diynot.com/diy/threads/cellar-ventilation.68784/

 

[LJD1974]

I don't think so ... I would guess they are there just to provide ventilation to the cellar.

Do you have plans for some ventilation / extraction? Trickle vents in windows are needed to help replace air in homes now they are all insulated well - a cellar probably needs an equivalent of trickle vents or an extractor fan to stop the build up of moist, stale air. So before covering them up, work out if they can be used for that purpose - fitting a ceiling extractor fan on one might solve problems down the line.

Some advice here: https://www.diynot.com/diy/threads/cellar-ventilation.68784/

OK. The basement will have windows/trickle vents, bathroom extractor, etc, so should be fine without ventilation between ceiling and floor above, but will look at insulation also.
Many thanks!