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...................
In my last house (built 1895) I took up the floor boards, laid fibreglass insulation across the joists and relaid the floors. It was cheap to do and blocked draughts effectively. It was very disruptive but the ideal opportunity to clear out masses of builders rubble, open up blocked air bricks, replace joists which had succumbed to dry rot and run cables through the void
Anna
-- Anna Kettle Lime plaster repair and conservation Freehand modelling in lime: overmantels, pargeting etc Tel: (+44) 01359 230642 Mob: (+44) 07976 649862 Please look at my website for examples of my work at:
Hi Anna,
Did you actually lay the insulation across the joists and then nail the boards through it or was it between them ?
Dont reckon, get a energy audit, the most important thing for an old home is a blower door test, the tech will pinpoint air leaks with a smoke stick and give you a printout of air exchanges per hour that you have , what it should be and what to fix. Spray foam would seal and insulate best. I was showed leaks where I never imagined they would be and fixed them
Across and screw through so there was good airflow under the insulation. I didnt want the rot to reoccur
Anna
-- Anna Kettle Lime plaster repair and conservation Freehand modelling in lime: overmantels, pargeting etc Tel: (+44) 01359 230642 Mob: (+44) 07976 649862 Please look at my website for examples of my work at:
The candle test works well too and can be done on a 'fix the big drafts and repeat the test to find smaller drafts' basis
Anna
-- Anna Kettle Lime plaster repair and conservation Freehand modelling in lime: overmantels, pargeting etc Tel: (+44) 01359 230642 Mob: (+44) 07976 649862 Please look at my website for examples of my work at:
Agreed.
Draughts are the promary cause of heatloss inmots old houses.
Fix these before anything.
I am intrigued by annas solution to using rockwool. I suppose it would work, but the slightly more orthodox way would be to wedge celotex between the joists, and I'd probably use expanding foam to fix and seal it as well, and tape over with foil tape before re-laying the floor. And attend to any underfloor gap to intrawall cavity spaces as well. If you have e.g. stud walls plasterboarded or lathe and plastered over.
Definitely use the opportunity of lifting the floors to do any cable renovation, and attend to underfloor ventilation as well.
We have in the past insulated the ground floor suspended timber floor by laying garden netting loosely over the joists, fixed with staples, then laying rockwool between the joists.
The only cost is the rockwool and we did this because the floor was coming up anyway but I would suggest that the energy savings do not justify taking the floor up just to do this job.
Much better, as others have said, to focus on filling gaps. Expanded polystyrene for the big gaps and strips of foam pipe insulation wedged between the floorboards for the small gaps.
Brendan.
I was thinking the rockwool solution would end up with bouncy floor but I suppose once its all screwed down it would be ok. One snag would be laying the insulation down carefully enough whilst relaying the floor - If you put your foot through it.... Also the effective insulation wouldnt be as effective as filling in the joist as the rockwool is compressed to almost nothing at the joist so you would end up with strips of colder floor.
That happens anyway. Its cold bridging par excellence, but fitting slabs between reduces joist heatloss to the bottom area of them only..
And you can improve matters slightly by laying e.g. insulation board over the joists before screwing the floor back down.
Candle test?
Who does that? (Yellow pages? any idea what section?) That sounds like it might be interesting.
heating engineers IIRC.
Phone BCO and ask,. I had one done on a new build.
They looked at plans, and calculated heatloss of all the elements, and solar gains etc.
A small flame is very sensitive to air movements..you use it to find draughts..heading upstream agsainst the way the flame bends..
Ta. Did it pass? :)
Ah ok. nowt more scientific than that. :) Thanks
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 suggestedChris
Thanks all for the useful suggestions and advice.
During the coming months as I get "Roundtuits" I'll tackle the draughtproofing a room at a time. I don't want to spend humungous amounts of money as the property isn't actually mine and is rented. But, with careful consideration to the areas needing the work done first I'll be able to reduce the draughts and lessen the bills.
Time to call in some favours for the building supplies companies I work at every day and get me some freebies ;-)
In my kitchen I laid garden netting loosely across the joists and rockwool on the netting between the joists.
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