What loft insulating material to use?

What "loft" insulation material would the experts recommend for my needs?
The only heating in the house consists of a wood burning stove in the living room downstairs. It struggles to heat the one room. Upstairs is currently not used, but has a few electric heaters on the few occasions anyone is up there. Above that is a very large loft space.
I want to lift the floorboards above the living room and put some insulation between the floorboards and living room ceiling. There is only around 4 inch gap. The joists are not evenly spaced.
The aim is to help keep the heat in the living room below. It gets very cold in the room in Winter. There is no insulation anywhere in the house at the moment, so heat just vanishes. Due to a large mezzanine type opening between the upstairs and the vast loft, there is just wide open space between the floorboards above the living room and the slate roof.
The house is very old (two hundred years +) with exposed beams, built in stone (two or three feet thick).
At some point in the future the roof and loft will need insulating properly, but the immediate need is just to insulate the living room ceiling.
Suggestions for insulation material?
--
David in Normandy.
(The free MicroPlanet Gravity newsreader is great for eliminating
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
David in Normandy wrote:

Standard Rockwool I would have thought. Cheap, versatile, and easy to lay, especially where spacing is uneven
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 8 Oct 2007 13:38:49 +0200 someone who may be David in

You didn't state what constraints you place on your choice of insulation material, such as sustainability or cost.

Far better to put in a heat recovery system to heat the rooms upstairs and insulate the loft. For the latter, wool or newspaper is more sustainable but generally somewhat more expensive.
--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
says...

Unfortunately the loft can't be insulated at the moment - or rather it would be a waste of time as there is a mezzanine sized hole between upstairs and the attic space, so any warm air would just drift up the "hole" and into the roof space. The "hole" will become stairs at some time in the future, but a lot more building work needs doing before then. The immediate need is to insulate the floor/ceiling above the living room.
As the gap under the floor boards is only around 4 inches I don't know whether to use Rockwool, vermiculite, or some of that new foil/bubble wrap stuff, Polystyrene or some other material? Preferably not a material that mice would find too comfortable to set up home in as we live in the countryside surrounded by lots of the furry little buggers.
--
David in Normandy.
(The free MicroPlanet Gravity newsreader is great for eliminating
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
ive just bought a similar house in herefordshire, an expert yesterday told me the recommended width of glass fibre insulation is six inches, not 4.
i think getting rid of water leaks and draughts is top priority,
and theres a spaceage insulation which is very thin but expensiver,,,
if the insulation layer is waterproof then wont the bilding be able to breathe?
i hope to hear good tips on this thread..
and someone else said i shouldnt be using woodburners into the coal chimneys cos of sparks from the wood...
http://www.diyfaq.org.uk/miscellaneous.html#Top is interesting on vapour and insulation but i cant find more online...
[g]
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
David in Normandy wrote:

effective, fireproof, dampproof, rotproof, low cost, indefinite life, some sound absorption

I suppose you could, but it would not be a first choice material

lot of question over the claims made with that stuff. Burns away in fire, little or no sound insulation, limited life, high price.

works. Flammable though, and easy to make nests in

sheep wool costs more, has limited life, burns, and is very cosy for mice. Fire retardant treated shredded paper burns in fire, is cosy for mice.

firebreglass or rockwool are the best bet.

NT
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 08 Oct 2007 14:09:38 -0700 someone who may be snipped-for-privacy@care2.com wrote this:-

Only on a limited range of criteria.
http://www.sustainablebuild.co.uk/InsulationMaterials.html explains some of the alternatives.
--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Oct 8, 10:09 pm, snipped-for-privacy@care2.com wrote:

I'd tend to agree, though with rockwool the fibres may go everywhere.
Spraying it with dilute PVA or bagging it in breather membrane may get round this.
cheers, Pete.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Pete C wrote:

Not a major problem IME. It's just so versatile when you have awkward spaces to deal with. Celotex is more effective, but is also more expensive and labour intensive

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The best you can use is xtratherm/Celotex/Kingspan which is rigid insulation that can be cut with a saw very easily. See http://www.insulateonline.com/index1.htm?products.htm~main for its characterisitcs and search the net for cheap suppliers (I have bought seconds quite a bit cheaper - boards with dings etc. in the edges). Because your joists are unevenly spaced this will be a pain but remaining gaps can be filled with expanding foam. It is more expensive than your next best bet (fibrglass or rockwool) but will do a better job and comes in a variety of thicknesses and sizes.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Yes I agree. I've used it in numerous applications in awkward places. Something like 90mm thickness board would be very effective.
It isn't very flexible though. Deliberately there are glass fibre threads embedded for strength. It should be possible to install it by removing several floorboards at one end of the upstairs room and then a few in places at intervals. Cutting a 2440x1220 sheet to width and then the 2440 lengths in half should be enough to fit it in. You can tape across the joins from board to board with a sticky foil tape.
This material should be available at builders merchants. I've never seen it at bricolage places in France.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Andy Hall wrote:

Note that tot all the various makes and versions have the threads... some are just plain PIR foam with foil over.

You could lay sheets of it directly over the joists without cutting it at all, and then relay the floorboards back on top of it. Screw them through the insulation boards into the joists. This is the same construction technique for a warm deck flat roof. The boards spread the load enough to stop the foam deforming.
--
Cheers,

John.

/=================================================================\
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

True, but I was trying to avoid a scenario of having to lift all of the boards.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
B+Q have half price insulation , knopf space balnket 6.98 each 2msquared
thermawra 13.98 4.5m squared
is this the best deal i can get?
and someone said i should wrap it in plastic but wouldnt that mean condensation?
george
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Dear David I agree with Nafuk. Get yourself a foam gun - some cartriges AND some acetone cleaner for the gun. Buy seconds of an unsulation such as Kingspan TP10 (all their urethane stuff is basically the same product with differnt names) - there is a good seconds place in N Wales but I doubt it would be worth it traipsing over to Normandy with it stuck to the top of the car! If you are sure that it is exactly a 4" gap then - you could go for 4" of insulation but I doubt with lath and plaster and the vagaries of timber dimensions that this is the case and you would be better off with 2" at the bottom of the void and 1" at the top. there will be a slight air gap which will do no harm. Remember to put on a vapour check on the underside of the GF to stop condensation (unless it is well vented - as it sounds) into the first floor. If the walls are stone - then consideration could be given to lining the inside with 2" of TP10 as well. I have sucessfully just done this in an old Welsh random stone wall 2' thick. I used the plastic washers and s/s nails they supply for external insulation on the inside and stuck on plasterboard with plaster board adhesive and more of the nails before pinking it - worked a treat. only risk is if there is water penetration from the outside as I ignored the Kinspan advice to batten out as I did not want to lose 4" plus of room Chris
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.