# Heat loss through floorboards



## wishbone (10 Feb 2012)

Hi there

Just wondering if much heat is lost through floorboards. Our house was built in the 50s I think, a regular 3 bedroom semi-d in suburban Dublin.  The ground floor has no carpet, we have floorboards or tiles.  The floorboards are the original ones which we sanded and varnished.  There are some gaps between some of the boards.  The house is built directly onto the earth ie if you lift a floorboard you see joists and then earth...so...would laying carpet or floorboards on top of these make the house considerably warmer?  Or should we just use a filler on the larger gaps?  Or is it worth it?

Just curious, you can feel cooler air if you place your hand over a gap.
Thanks!


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## Mommah (10 Feb 2012)

I'm no expert but have personal experience.
Yes you do loose heat.
Yes, a carpet would keep it warmer.
Filling the gaps with filler is a waste of filler and your time.
The boards are flexible and move as you walk, as they get hot/cold, so the filler falls out.

The gold standard solution would involve lifting all the floor boards.
Digging out the underfloor and putting in hard core, insulation and concrete and then the flooring of your choice on top.
You will also have to repaint your entire downstairs.
Depending on the size of your house this would cost a few grand.
We did this, as part of a bigger job and it has been amazing.


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## serotoninsid (10 Feb 2012)

Isn't it possible to fix a spray on insulant onto the undersides of the boards?


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## lowCO2design (12 Feb 2012)

wishbone, carpet with thick underlay is an option but will not solve the  problem entirely, I have to disagree with Mommah's concrete solution,  an old house doesn't need that level of invasive work to reduce cold air  from a suspended timber floor. Serotoninisd - I don't know of a product  that can be installed like that, unless you lifted a small area of the  floor to crawl into and found you had 4ft space to work in below,  otherwise  its just not practical. 

the space below the timbers must retain ventilation so moisture can  dissipate and does not lead to damp/mould/rot, that's why the majority  of these homes were and are still build with vents at that level -  (you'll often see old perforated bricks or metal  grills near the  footpath level on suspended timber floor buildings - and these should  not be blocked)

best to deal with the drafts and cold as two separate things - one requires insulation the other an air membrane/barrier.

1. lift floor boards, removing skirting if necessary (you may wish to number the underside of boards for relay)
2. check space underneath, ensure vents remain open, check if there is any damp/required timber replacement 
3. lay hemp cloth or similar material between joists (or chicken wire or geo-textile)
4. install insulation preferably sheeps wool or hemp but mineral wool (rockwool or equil will be fine)
5. install Vapour check (same thing as an Air-tightness membrane and tape/seal with correct product to the wall perimeter  
6. reinstall floor/skirting

best of luck with it.


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## wishbone (13 Feb 2012)

Thanks everyone for the replies.  It's very interesting to see the options.  Vents exist alright, you can see them on the front of the house.  Will speak to him indoors now and we can then make a decision together.
Thanks again.
Wishbone


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## mark1 (13 Feb 2012)

My parents in law live in similar house and were having the same problem, there wasn't a huge budget so we took up a section of floorboards and got in underneath, we cut board insulation and put it between the joists, then took off skirtings,door saddles etc and laid another lot of the insulated underlay on the existing floor and laid a new laminate floor over, replaced saddles etc and trimmed the doors, it's been really warm since


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