Project: Insulate House - the floors

digital_biscuit

Hi All

We have a very cold house and I am trying to get it all nice and cosy and reduce our soon to be astronomical gas bills.

Next task is to start and tackle the flooring. I have had a look on the net and there are many different methods which I see people suggest, but never report back on what they ended up doing and how well it worked.

So, can anyone offer up any suggestions on floor insulation. I ideally dont want to lift the boards up as I doubt the wife will allow me to tackle that job!

Thanks very much!
Darren

baldelectrician

I have put 100mm kingspan between my floor boards downstairs.
It was really awkward to do and cost me nearly £150 but it has saved me at least that each year since it was done

Hintza

Decent underlay and carpet?

paulmapp8306

Underlay and carpet wont do it as its not insulating material. It may help a little as a byproduct of what its designed to do, but it will be that - a little bit.

The boards are the only propper way I believe, and while you can get them from as 10mm, you really need 100mm plus - or its like putting 10mm in your loft.

Unfortunatley you almost certainly need to lift the floor to do it - otherwise yor carpet will be 10cm higher than it is know and the doors will almost certanly not open !! If you underlay/carpet is layed directly onto a concrete base (as mine are - its a 1960s house) then it not even possible to fit them as far as I know.

System

can you get below the floor (i.e. squeeze down anywhere?)
you could get rolls of insulation and some netting to put between the floor joists, only thing is you'll need/want some proper breathing gear if you are doing it without lifting the floor, if you can't fit under there then there is nothing you can do without lifting the floor

digital_biscuit

Ok, so lifting the floor it might have to be! Getting that past the wife will be fun!!

the_r_sole, you mentioned maybe squeezing under, now I may be able to do that, what sort of breathing gear will i need?

Cheers!!

gmgmgm

I have good access under our floors and insulated them with 100mm of foam. Fairly easy and seems to be well worth it.

If you don't have easy access, then at least check for any draughts and block those up- that's going to be 80% of the benefit for an hour of work.

Then put a thick rug on top :-)

digital_biscuit

In terms of sealing gaps, would you seal between floorboards? I think they are tongue and groove, would you seal those? If so, what with?

Many thanks again!

gmgmgm

If you have tongue-and-groove floorboards and they're in good shape, then it's unlikely you have any gaps. Do check though.

You can fill gaps with various things- PVA+sawdust, bunched-up clingfilm (killer tip for sash windows) or proprietary tape.

lgooding

I found using Insumate as a quick way to insulate, which I did from beneath but I can't see any reason why you could fit them from above.

cyclonebri1

Whilst I agree about getting under the floor being the only way, (I did this 15 years ago when we replaced all the downstairs floors), the idea is to insulate the floor, not to seal all gaps.

Every house need some ventilation and a little seeping in from below is beneficial to keeping the house DRY, again the idea is to prevent a cold floor rather than making the room airtight.

200mm rockwool with stapled netting, (get the stronger stuff), worked for me.;)