Insulating crawl space (beneath floorboards (

[Cosmos123]

Has anyone done it?
Has it made a difference in terms of how warm your house is?
Finally what type of insulation was it?

Haven’t done it but watching as we were going to rip up the carpet in our doer upper and sand and stain the original boards but when we lifted one to check the crawl space it was honestly like opening a window! So currently ours is ‘insulated’ on top with plush underlay and really hideous carpet until we can work out what to do.

Yes there is a definite draught. Important not to block the airbricks.

Hopefully someone will come along soon..

Yes we did this and it has made a huge difference to how warm the house feels, we replaced our wood floor throughout downstairs and did the insulation then.

Sorry, we used sheets of Selotex (sp?)

Celotex.
We did it this summer with cheap rolls from B&Q made from recycled bottles. It's not as highly performing as Celotex or Rockwool but it's not itchy (or expensive.) We'll see how warm it is this winter but it can't be much colder than last winter.

@wineymummy

Celotex. We did it this summer with cheap rolls from B&Q made from recycled bottles. It's not as highly performing as Celotex or Rockwool but it's not itchy (or expensive.) We'll see how warm it is this winter but it can't be much colder than last winter.

Hi winneymummy Do you have a crawl space or did you lift the floorboards up?

Lifted the floorboards (lifted enough that me and DH could pass it between us under the boards, suspended on netting.) No crawl space.

It’s a lot easier to do ( and a better job ) if you take the floor up , but you can get under and fill between the joists with insulation and then put lathes or a net etc to hold it up and stop it falling out.

This is how it’s done without the floor down, I always prefer the solid insulation board to the rolls .

Interested in doing the same but whenever I read about internal insulation I get overwhelmed as there's much talk of condensation / causing damp / air space etc. We have bare floorboards with rugs downstairs while we renovate and decorate ( v slowly) but interested in putting insulation down before hard flooring, probably bamboo. Our crawl space is too small to actually crawl under (electrician tried when rewiring the place) so it would be a case of lifting floorboards. Sounds like a big job and would need a build up to cope with the disruption...

I had a company do mine under the Green Homes scheme. They cut a trap in the under stairs cupboard and crawled underneath the floor. I only had it done this summer but I do think the house is warmer.

We did the same as @Chumleymouse - we also insulated our north facing walls when we renovated with a special type of thermal plasterboard - our house is seriously warm, and it was totally worth the effort and extra expense

@Stretchandsnap please tel me more about thermal plasterboard ! We have bare plaster on a big cold wall next to the stairs . Was going to get it skimmed by a plasterer but thinking it needs something warmer doing. Would need to be diy though.

My OH is currently halfway through this job - in the crawl space with some secondhand thermal boards. It’s is already making a huge difference.

We have done this on some downstairs rooms. The floors have air bricks and space for air to circulate, then we added Kingspan between the joists and put the floorboards back on the top.

It's made a massive difference to the warmth of the house.

It's mostly draughts you need to block, especially round the edges of the room. It's easier to do if you have the floor up for any reason. Mineral wool is good because it can be squeezed between the joists to block draughts. You have to leave the space under the joists clear, and the airbricks, so the airflow keeps the void dry.

Think we will save this job til warmer weather before laying new floor. Priority for now is draughts and topping up loft insulation (currently partial and 15m max) - my research suggests this will be most effective re. Saving energy .

*150mm

@TiddleTaddleTat I am not sure what brand we used but it was like normal plaster board with an extra 6-7cm of insulation attached - it just goes on the wall like normal plasterboard and the you skim it like normal - I don’t remember how much we paid - we did it about 10 years ago when we did a big renovation but it has really made a difference