Insulation above integral garage

[Malpas mum]

I have a new(ish) build house (groan you say). The bedroom above the garage is cold, when it eventually reaches temp it quickly loses heat. There is insulation in the roof and the floor with the garage below (checked). Cavity wall insulation in place and area around the window sealed.
Below the garage has multiple air gaps. The insulation is mineral wool same as internal ceilings. Is this correct? I can’t find min standard in the regs. Seems odd that it wouldn’t be a higher grade given it’s effectively next to an external space. I’m considering getting a report from a building surveyor but not sure whether it would be worth it so just wanted to know I’m not wasting my time and money. thanks.

 

[oldbutnotdead]

How many external walls does this room have? If (my suspicion) it has 3 then it will lose heat more quickly than the other bedrooms (with only 1 or 2 externals).
If you can get under the floor easily enough, make sure the whole void is filled with insulation. Check for draughts, deal with them.
Building regs are often a minimum standard rather than a gold standard iyswim

EDIT If it is a new new build & you have a warranty then get onto the builders and get them to verify what should be there and what is there.

 

[Malpas mum]

Thanks for your input. It has two external walls and we had the floor checked for insulation at numerous places when still in guarantee. The rest of upstairs is toasty just the one room so I think it has to do with the garage.

 

[oldbutnotdead]

The rest of upstairs gains heat from the downstairs rooms, that bedroom doesn't so yes you're quite correct.
Might be worth doing a heatloss calculation on that room and one of the others, see if the radiator is undersized (Google heatloss calculator).

 

[^woody^]

If it's a new build it may well have a suspended floor insulated to a lower approved standard than say an extension or other retrospective work would be.

That floor is presumably going to be between 150 and 225mm thick, and even if full of quilt the insulation value will be crap, and the joists will be thermal bridges. The only real way to deal with these cold floors is to redesign it with better insulation and remove the thermal bridges, and deal with any air gaps in the floor void while you are at it.

 

[Deleted member 292770]

and when all that’s sorted install underfloor heating.

 

[Malpas mum]

Thanks for your replies. All this talk about being energy efficient and green and it seems the regs don’t require new homes to protect against this sort of heat loss - it’s crazy to me.

 

[^woody^]

And that's the point.

All that talk is just talk, tokenism

 

[cdbe]

A typical upgrade would be 100mm celotex insulation boards fixed under the existing ceiling, with a suitable layer of plasterboard to provide fire protection. Put the money you will save on a "report" towards it.

 

[^woody^]

A typical upgrade would be 100mm celotex insulation boards fixed under the existing ceiling, with a suitable layer of plasterboard to provide fire protection. Put the money you will save on a "report" towards it.

Typically bad?

PIR should always insulate the warm side. And lining a ceiling does nothing for any gaps within the floor void.

 

[mikeey84]

Typically bad?

PIR should always insulate the warm side. And lining a ceiling does nothing for any gaps within the floor void.

Whys that?

Edit- the warm side part, not the gaps

 

[^woody^]

Because that's how it is more efficient. You don't want the heat from the room to get into a cold space, or a cold wall first, you want the PIR to insulate the room.

 

[mikeey84]

Because that's how it is more efficient. You don't want the heat from the room to get into a cold space, or a cold wall first, you want the PIR to insulate the room.

Does thermal mass not play a part (maybe not in this example)

 

[^woody^]

Thermal mass considerations are more for the structure to be heated by the sun and realise the heat later or the building being kept cool when the sun is blazing, or generally keeping a building at a more even temperature.

What you don't want to happen is to spend money heating the structure unnecessarily, rather than keeping the heat in the room.

 

[mikeey84]

But if its externally insulated then won't the structure radiate the heat back into the room?

I thought that was one of the reasons external insulation is preferable to internal...