Floor Insulation

[SwingsitlikeHogan]

Inspired by the Loft Insulation thread…

With work now well underway on our back extension, work on the inside will start in a month or so.

Tons of insulation in the structure of the extension ‘beam and block’ floor…but of course there is none under the suspended floors of the rooms we are knocking together and onto which the extension is built.

Is it worth having all the floorboards up and putting some form of insulation between the joists? We’ll be putting down some form of decent vinyl or similar flooring boards on top of the floor boards, and I expect that that’ll have some form of thin underlay? At moment I’ve been thinking that that’ll be sufficient, but the cold snap has very chilly drafts through the gaps between the floorboards, though temporarily there is a lot more air getting in while the new air ‘bricks’ are sorted, and if we are going to do more, then we need to decide fairly pronto.

 

[GreiginFife]

100mm PIR insulation between floor joists. Sealed around the edges with expanding foam.

If you are going for the extent of building an extension and properly insulating that, you’d be daft not to just lift the floor boards and take the opportunity to insulate properly elsewhere.

We did this when renovating downstairs as we had all the flooring up and we have a crawl space under the ground floor to make it easier, and the difference is insane.

 

[Jason.H]

We have a small extension to the side for boot room, wc, utility etc and that was already built when we bought the house. It’s really cold in there I imagine there is no cavity wall insulation or in the roof. Worth doing imo.

 

[PJ87]

If I was doing work in the house anyways I would look at it. Doesn't seem too expensive for what you gain

I'm going to have to save for solid wall insulation, might be a walk at a time ATM

Going to dot and dab one interior wall in the living room that gets condensation (then mould forms) just to fix that issue cheaply before can do it oroper

 

[larmen]

As I am in a youtube spiral of house renovation videos this popped up on my screen today

If you are happy too and able to lift the floor boards it looks doable.

I also had the shouty youtube builder guy on explaining what he did, but I am not linking his video.

 

[SwingsitlikeHogan]

If I was doing work in the house anyways I would look at it. Doesn't seem too expensive for what you gain

I'm going to have to save for solid wall insulation, might be a walk at a time ATM

Going to dot and dab one interior wall in the living room that gets condensation (then mould forms) just to fix that issue cheaply before can do it oroper

Our builder, a very experienced guy who has done lots of extension builds like ours…it’s his bread and butter - had a think and suggests that it might not be worth it and might not make that significant a difference if we put down a laminate floor over good t&g flooring with a foam or similar underlay. Will ask for a price in any case.