Cavity wall insulation on ground floor of house only?

[itm2]

We've just had someone round to quote for CWI for our 3-storey townhouse. The basic quote was £1,900, but due to a very narrow side alley scaffolding
would be necessary to access everything other than the ground floor. This would add £1,000-1,500 to the price.
Our main priorities are 4 rooms:
- Master bedroom on the top floor: The surveyor said that the main external wall of this room wasn't a cavity wall, so only the shorter external wall could be insulated
- Kitchen on the 1st floor: This is fully fitted, so the fitted furniture provides a degree of insulation. It has a large window and a semi-glazed door - we are planning to buy thermal blinds to mitigate heat loss from these
- Study on ground floor
- Lounge on ground floor: this is a single-storey extension, with 3 exterior walls.

Since the largest exterior wall of the bedroom can't be fully insulated anyway, and the kitchen has fitted furniture providing some insulation, it would seem sensible to focus on the two ground floor rooms - particularly as this is where we spend the vast majority of our time.

My question is: would it be feasible or sensible to insulate the ground floor only - hence massively reducing the cost and targeting the spending at the most important areas?

 

[23vc]

I’d worry that the heat retained by insulating downstairs would go up and be lost upstairs. Might want to look at internally insulating upstairs walls?

 

[itm2]

Yes I guess that's true. However at this point I think the only option would be a series of incremental upgrades. If CWI can't be cost-justified for the whole house, then room-by-room insulation - as and when we choose to redecorate each - will be to most practical approach.

 

[ETAF]

- Lounge on ground floor: this is a single-storey extension, with 3 exterior walls.

do you know when this was done ... and is it already insulated, not sure when building control would have required insulation on extensions, i maybe wrong , but think new builds in the 90's

i suspect the quote would have checked - but i have had builders who have quoted for things already done , years ago

 

[itm2]

No I don't, but the surveyor stuck a camera into the cavity and it was empty.

 

[^woody^]

I doubt the installation could be self-certified to building regulations, or if the warranty would be valid if a wall is part filled.

You should check first. Blown insulation is not like other insulation in terms of partial or incremental installation.

Technically, the risk is settling and damp within the cavity above the insulation.

 

[JohnD]

Waste of time fooling about with a half-arsed job.