On 19 Oct, 20:31, "RW" wrote:
Ok, since checking our "Carbon Footprint" and realising I'm chucking away
sh*tloads of £££s in lost heat costs because of draughts in our 1896
semi-detached solid wall cottage I reckon the only way left to insulate
(Given that it's already DGd and has 200mm of loft insulation) is to stop
the draught under the wooden floors downstairs.

So,
Who's done what and what has it cost with a ball-park pay-back period....

Let the thread commence...................

Dear RW
Define Sh** loads first. Generally about 10% of the loss of heat in a
house goes downwards but with a leaking ST floor that may well be
more. Most people have floor coverings of some sort.
Once you know what you are loosing you can work out the capital costs
and payback to rectify the losses.

The cheapest way is to lay a good underlay and carpet.

If you want wooden floors then there is a spectrum of responses
starting with the most expensive

1) get rid of all the ST floors and put in solid with as much
insulation as poss under and tack floorboards on the top (not even
remotely likely to be cost effective but if (and only if) you have to
replace the floors anyway due to rot....ok. Note this is an all or
nothing not just one room as you have to maintain sub-floor
ventilation
2) lift up all boards - put polythene on oversite and blind with sand
or the like to check water vapour coming up from the ground - fit TP10
or the like (PU foam) to the depth of the joists and foam up any gaps
really well - lay SDQ (sound deadening quilt) to provide draft
proofing and a nice surface bounce for the boards - lay boards close
fitting (will not be possible to use floor cramps as no access to
joists so use folding sliding wedges off battens nailed to joist
through paper of SDQ) and varnish the top with a vapour check of PU or
the like
3) staple netting to the underside of the joists and put in Rockwool
batts or the like and as above
4) have a slight step up into the room and lay thin insulation on the
joists as Anna suggested

Chris