Underfloor insulation for a raised floor

[adrian.teasdale]

hi there. We have bought an old Schoolhouse from the 1890's that was converted around 1982 into a home. The Lounge has a mezanine level, meaning that its double height for much of it and there is a raised floor are that is a good few feet heigher than the ground outside. We bought the house just before the summer and when it was windy the lounge became incredibly cold with cold air coming in along all the skirting and up through any gaps in the flooring. I thought it might be a good idea to insulate, but I'm not sure where to start. I was wondering whether to put some form of insulation underneath the floorboard or whether to fill the space with some kind of insulation. Would appreciate any comments as I'm planning on doing this work soon before it starts getting cold again and my wife threatens to move out!!

Thanks in advance if anyone has any suggestions

Ade

[Phil Anthropist]

Personally I would go for draught proofing on the basis that most heat rises.

[Dave Fawthrop]

|hi there. We have bought an old Schoolhouse from the 1890's that was |converted around 1982 into a home. The Lounge has a mezanine level, |meaning that its double height for much of it and there is a raised |floor are that is a good few feet heigher than the ground outside. We |bought the house just before the summer and when it was windy the |lounge became incredibly cold with cold air coming in along all the |skirting and up through any gaps in the flooring. I thought it might |be a good idea to insulate, but I'm not sure where to start. I was |wondering whether to put some form of insulation underneath the |floorboard or whether to fill the space with some kind of insulation. |Would appreciate any comments as I'm planning on doing this work soon |before it starts getting cold again and my wife threatens to move out!!

If you can get under the floor without problems insulation is a good idea, but make sure that whatever you use draught proofs as well. Beware the glass fiber rolls you use in ceilings, it will fall down on your head and itch like mad. There is now some glass fiber roll which is supplied in polythene, which would be better, but see if it will fit between your joists. You can hold it up to the floor boards with industrial staples, or polypropylene string between clout nails into the bottom of the joists.

Insulating floors is not as economically justifiable as ceilings because hot air rises, and it takes a lot more time to do. Newspaper bunged under the skirtings would be a good idea.

[The Natural Philosopher]

Easy first step is to nail down hardboard, tape the joins with duck tape and caulk the skirtings.

Then lay a decent carpet.

This will net you a 300% improvement. To get the last 100%, rip the floor up, lay kinsgpan/celotex between the joists, tape over joints with Al tape to utterly seal, caulk and foam any gaps, and re-lay the floor of your choice.

[noelogara]

The Natural Philosopher wrote: > >

thats a fairly big job and he may like to keep his wooden flooring. An easier first step would be to identify exactly where the draught is getting in through the walls and try to seal those gaps up but leave a very small aperture for the benefit of the timber to breathe. You could seal it fully for most of the year and open a vent for summer months and this would suffice. If you look you will probably find several bricks with holes around the base of the walls on the outside. seal them with tape for a trial and see if it stops the draught. The only other place is the door or windows but bear in mind that you need some circulation of air. Pity the poor school kids who had to endure that cold needlessly.

[Andy]

I put in rockwool roll under my dining room floor when I had the boards up, you need a spacesuit to keep the stuff away from your skin as you're directly underneath, as another poster says. I found a boiler suit, long gloves, a scarf round the neck, a mask, goggles and a cap were just about sufficient.

I suspended the rockwool between the joists by hammering in nails along the joists and then stringing some wire I had between the joists via the nails in a crisscross pattern, all very time consuming.

I believe there are easier ways to do it, perhaps that compressible polystyrene foam stuff which is for that very purpose, or maybe using plastic sheet stapled to the joists to hold the rockwool in place etc.

I do know that what I did works, as I acquired an optical IR thermometer, and I found there was a definite 1-2 degrees Fahrenheit difference between the temperature of the floor insulated underneath and a section of floor where I knew there was no insulation since I had run out of rockwool at that point!

As another poster says though, no point spending lots of cash on insulating your floor as the benefits are less than, say, getting cavity wall insulation.

Andy.

[marvelus]

In the winter water condenses in the unheated underfloor area thats when you *need* the airbrick ventilation.

[marvelus]

Celotex cut to fit between joists then some gripfill or something to glue it to the boards held in place with nails while it dries. Seal up any gaps with expanding foam.

Depending on your crawl space height can be a hard and painful job.

A victorian school would have extremely tall ceilings to allow good lighting. Its going to be difficult to heat anyway.

[The Natural Philosopher]

Er, no, it doesn't. Thats why you tape over all the joints with the waterproof tape. To stop warm internal air reaching the cold parts.

Underfloor vents IME let in as much damp as they allow to get out..in fact, they have to don't they? Cos there is no other ay for it to get in..other than through the soil..and that reaches equilibrium fairly quickly.