Block and beam floor- insulate underneath

ssray · 23 Jan 2018

Our kitchen extenstion has a room underneath it as the garden is about 9-10ft below back door height and we built up from ground level.
The floor is block and beam, am I correct in thinking I can use 50mm celotex etc inbetween the beams and attached to the blocks by low expand foam stuff then use full sheets across this with either plasterboard attached or attach plasterboard later
Ta Ray
Photo below, the 3window bit is kitchen and the bit below has french doors in the big gap

ssray · 23 Jan 2018

noseall · 24 Jan 2018

Typically B&B floor beams are set at 150mm below Existing floor levels as to allow an x mm thickness of insulation plus screed.
You can insulate from below but I don't envy your fixing anything from beneath.

tomfe · 24 Jan 2018

ssray said:
thinking I can use 50mm celotex etc inbetween the beams

Why was it designed like this?
You'll have loads of thermal bridging though the beams.
If you have to do this, you could full fill under the blocks with rockwool and then stick rigid boards under the beams. Silly idea though

freddiemercurystwin · 24 Jan 2018

tomfe said:
Why was it designed like this?
You'll have loads of thermal bridging though the beams.

He intends on doing a continuous layer of insulation beneath the beams. Or do you mean at the ends? Presumably there is cavity insulation to prevent that?

Doggit · 24 Jan 2018

Put in a false ceiling, and insulate between the joists; then you've got something to plasterboard on to.

ssray · 25 Jan 2018

The builder did it like this, I would like to completly cover it with insulation, that would also become the ceiling of the garden room

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Block and beam floor- insulate underneath

ssray

ssray

noseall

tomfe

freddiemercurystwin

Doggit

ssray

DIYnot Local

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