Insulation this winter...

|This years comfort improvements includes insulating the underside of a |suspended floor. The floor is plain T&G boards sanded and varnished. With |a single soldier wall and standard joist construction. | |What are good simple & cheap solutions. I've had enough hours recently |under the floor in 3ft of 'head'space so it does need to be simple. |Insulation and some method of keeping it there. I suppose the simplest is |kingspan type which'll just wedge fit, but it is a little pricey. Though I |guess just cutting out the draft through the T&G will be biggest benefit so |I don't think it needs to be thick what withhot air going up. | |Anyone any good ideas? and are there any BRs I need to be aware of?

Hold the insulation up with polypropylene string, wrapped round clout nails driven into the joists. Alternatively stapled upwards into the boards, with a large stapler.

Beware of plain glass fiber rolls, the roll falls on your head and itches terribly. :-( There are now available rolls covered in polythene, if I were doing it again I would use those.

Because of the effort the payback time will be a lot longer than insulating the loft.

The message from Dave Fawthrop contains these words:

I was going to comment that effort doesn't cost anything - but then I remember that I spent yesterday getting two network cables from the conservatory and the daughter's bedroom back to the router.

Perhaps wireless networking really is a good idea.

You could try radiant heat barrier/foil type insulation. Works best when the heat flow is downward, so would be ideal for underfloor, and would stop draughts.

I'd just staple it to the underside of the joists with 'pads' of thick cardboard between the staples and the foil.

If you get condensation (fairly unlikely IMHO) it will tend to run into the middle of the foil than stay around the joists, so it should be easy to check for.

cheers, Pete.

Or juts wahck it up with 'no more nails'

Yup. Also, it sounds trivial, but the effect is immense, make sure that the whole assembly is totally AIRTIGHT. My experience is that a slot a couple of inches long and a few mm wide can destroy half the effect of decent insulation in a icy windy situation. Foam in a can is a useful thing to go roiund with afterwards to seal everything up with.

On Tue, 15 Aug 2006 01:39:36 +0100, The Natural Philosopher wrote:

|Dave Fawthrop wrote: |> On Sun, 13 Aug 2006 22:37:14 GMT, "VisionSet" wrote: |> |> |This years comfort improvements includes insulating the underside of a |> |suspended floor. The floor is plain T&G boards sanded and varnished. With |> |a single soldier wall and standard joist construction. |> | |> |What are good simple & cheap solutions. I've had enough hours recently |> |under the floor in 3ft of 'head'space so it does need to be simple. |> |Insulation and some method of keeping it there. I suppose the simplest is |> |kingspan type which'll just wedge fit, but it is a little pricey. Though I |> |guess just cutting out the draft through the T&G will be biggest benefit so |> |I don't think it needs to be thick what withhot air going up. |> | |> |Anyone any good ideas? and are there any BRs I need to be aware of? |> |> Hold the insulation up with polypropylene string, wrapped round clout nails |> driven into the joists. Alternatively stapled upwards into the boards, |> with a large stapler. |> | |Or juts wahck it up with 'no more nails' | |> Beware of plain glass fiber rolls, the roll falls on your head and itches |> terribly. :-( There are now available rolls covered in polythene, if I |> were doing it again I would use those. |> |> Because of the effort the payback time will be a lot longer than insulating |> the loft. | |Yup. Also, it sounds trivial, but the effect is immense, make sure that |the whole assembly is totally AIRTIGHT.

No insulation is totally airtight, Just draught proof is IME good enough. If the floor joists are on the same spacing as ceiling joists, normal insulation will fit well enough. An advantage of such insulation is extra draught proofing.

|My experience is that a slot a |couple of inches long and a few mm wide can destroy half the effect of |decent insulation in a icy windy situation. Foam in a can is a useful |thing to go roiund with afterwards to seal everything up with.

The message from Dave Fawthrop contains these words:

Perhaps the easiest way to draughtproof it would be to use battens along the bottoms of the joists holding polythene sheet up. Something like a damp-proof membrane.

Well, shades of meaning. They even pump water out of watertight ships...

The point is a very small hole can compromise an awfully large area of insulation..

Shouldnt have damp proofing on the cold side.

The message from marvelus contains these words:

Ah. A good point and well made.