Insulate lounge ceiling

Spinybif

Lounge is actually the old dining room, patio doors removed and knocked through into new conservatory with insulated mock tile roof. Despite new radiator it never really feels warm in winter. 

Due to a leak plasterboard ceiling in original half of room will have to be replaced. Would it make a difference if we installed fibreglass insulation at same time. Above is heated bathroom & bedroom which are always warm.

ThisIsWeird

Possibly. It all depends.

Why is that room hard to heat?
Is the rad undersized? (Who sized it, and was it 'oversized' taking into account current/future boiler efficiency? I suspect, by your issue, no.)
Is it due to being open to the conservatory? Has additional heating been allowed for this usually hard-to-heat room?
Any other external walls to this room? If so, which direction do they face? What level of insulation do they have?
What type of floor - solid or suspended? If the former, is it insulated? If latter, is it draughty?
And then you come to the ceiling... The rooms above seem to be fine, so something strange would have to be occurring in the ceiling for it to be cold enough to cause your issue. Not impossible, but the least likely of all potential causes. But would it make sense to insulate it since the ceiling needs redoing? My take is 'probably', as often the ceilings are open voids, draughty to the wall cavities, so potentially cold. But please don't expect a transformation. It'll be tricky to get loft insulation up there defying gravity, so perhaps 'rigid' might be easier. 

Spinybif

Conservatory was replaced 4 years ago, argon filled heat reflective glass. Heavy Roman blinds. Two walls are internal, external wall faces west with rockwool cavity fill.  Radiator was replaced & increased in size when patio doors removed for which building control were involved and SAPs calculations done.

Floor in suspended concrete block, 10mm underlay with carpet

ThisIsWeird

Spinybif said:

Conservatory was replaced 4 years ago, argon filled heat reflective glass. Heavy Roman blinds. Two walls are internal, external wall faces west with rockwool cavity fill.  Radiator was replaced & increased in size when patio doors removed for which building control were involved and SAPs calculations done.

Floor in suspended concrete block, 10mm underlay with carpet

Thanks. I'm stumped, then. Nothing sticks out as being the culprit.

Size of sitting room, and size of connie, and size and number of rads?

The connie roof will, of course, be very well insulated? Is it vaulted or flat - or a bit of both?

Spinybif

Vaulted with thick foam insulation. One large K2 radiator - not sure of size as at work today.

ThisIsWeird

One rad between both rooms, or one rad in each?

Spinybif

One between the two

FreeBear

Spinybif said:

Lounge is actually the old dining room, patio doors removed and knocked through into new conservatory with insulated mock tile roof. Despite new radiator it never really feels warm in winter. 

Due to a leak plasterboard ceiling in original half of room will have to be replaced. Would it make a difference if we installed fibreglass insulation at same time. Above is heated bathroom & bedroom which are always warm.

Without an exterior grade door between the conservatory and the main house, the conservatory should have been built to a high enough standard to pass building regulations. Highly unlikely that it has, so insulation in the floor, walls, and roof will be insufficient, and the large expanse of glass will be sucking heat out. If you had wanted a warm comfortable living space, you should have had a proper extension built.

Putting extra larger radiators in the lounge & conservatory will go some way to offsetting the heat loss at the expense of increasing your heating bill. But that is only a short term "after the event" solution. The best answer would be to fit an exterior grade door so that the conservatory can be isolated from the rest of the house in the winter.

markin

I think i would use 50mm rockwool just to keep the bedroom cooler and help with noise.

stuart45

When the SAP ratings were done, were improvements made to the main house (insulation and heating system), to make up for the extra glazing?
This sometimes means that the conservatory and room next to it will still lose more heat than the rest of the house.

Spinybif

No improvement needed to meet SAPs requirements. Already cavity wall insulation, deep loft insulation, newish double Glazing and solar panels.