Suspended floor insulation & general energy saving!

[Rob_B]

Hi guys, does anyone have experience with insulation a suspended floor? Our hall/living room is probably losing a load of heat through the floor as there is nothing but a couple of foot gap to foundations and I can feel/see a breeze if I look under the floor.

I can’t really remove the boards so it’s a case of putting something down there or getting a hole big enough for me and doing it myself from underneath somehow.

I don’t really know where to start, from looking around it seems you should insulation from the bottom of the boards down and leave a gap on the floor for ventilation, there is talk of suspending nets, using insulation blocks or just using plain old loft insulation and using netting or something to hold it up to the boards, is that about it?

For the sake of cost vs impact I’m thinking to use normal loft stuff, get under the boards and fill the gaps between joists while using netting or something to hold it up. Is this a good idea or am I way off?

My dad has mentioned something about foam pellets (like beanbag filling) that can be sprayed under the floor to fill the gaps, I’d imagine this would work but there would be no ventilation and there would end up being a gap directly under the boards which is what I’m trying to get rid of (?)

For completeness I’m currently in the process of applying for EDFs free cavity wall/loft insulation programme and also trying to replace all of the R50/MR16/GU10s in our house with LED versions but it looks like its going to cost me a fortune so it’s a long process!

Any help would be much appreciated!

Rob

[stevie lee]

when we had the loft done, we had underfloor insulation put in.

new joists where put down, then wire mesh was nailed near the top of the joists, going in a U shape to the next joist. Then the wool/foam insulation was put in that, floorboards screwed ontop. its lovely and warm in the loft at the moment. its just insulated and theres no heating system needed up there.

you could probably, from below, nail one side of the mesh on, push up the insulation into the gap between the joists, then nail the other side of the mesh on if you don't fancy pulling all your floorboards up.

the stuff we have is Space Loft Roll - from homebase. any wire mesh thats cheap will do, theres barely any weight to the stuff. heck, even bits of wood nailed across the joists could hold the insulation up

[Max Tractor]

Air needs to circulate around that found gap, but it does not need to circulate onto the floorboards/caber board. I would suggest cutting a trap door, working out the size needed and looking into pricing celotex/kingspan(comes in sheets) or something similar, it is expensive Id recommend min 75mm for underfloor but it is really worth it if done correctly. 2 man job, somebody upstairs cutting the other in the found measure and install, if you measure/cut well it will fit in nice and tight, then a couple bits timber to final secure once it is in.

cheers

[Rob_B]

stevie - thats what I'd imagined, ie hanging mesh to hold it in, only I'd not be able to take all the boards up.
As max says it would probably mean cutting the boards at some entry point, I dont have the money or time to go the whole hog just yet so might have to hold out for a bit

On a related note: What has happened to all of the cheap energy saving bulbs?! You used to get them 3 for £1 but now they're £3.50 each! Also getting hold of MR16s is a pain/expensive! I guess now they have the market cornered they don't need to be so cheap

[Max Tractor]

Also, cavity wall insulation, seen them use blown newspaper/foam and saw these cause dampness, a cavity is there for a reason I never liked the idea of filling it. Apparently rockwool is used now but I can't comment on it

[stevie lee]

what kind of floor covering do you have? is it sanded floorboards/laminate. or is it carpets?

if you cant get underneath the floor, i would imagine (complete guess) that a nice thick carpet with maybe an extra layer of underlay would keep the heat in. although saying that, heat rises, so it will keep the draught out

[Sputnik]

I wouldn't have thought you'd lose alot of heat through the floor for the reasons already pointed out. you need ventilation under the floor to prevent the timbers from rotting.

I'm also not a great fan of filling wall cavities but, having said that it appears all new houses have sheets of insulation put into the cavities when they are built.

I bought some energy saving bulbs from Morrisons a couple of months back for about 10p each. If you have a look at Screwfix they have some on stock clearance at the moment for about £1. I was looking at the price of LED bulbs and they are still very expensive it seems.

[Rob_B]

I've never really thought about cavity wall insulation like that, I guess it makes sense but if it's such a heat waste it should probably be done (?!)

I'll check screwfix out for bulbs, need about 9 R50 style, about 8 GU10s and 5 MR16s, MR16s in B&Q (granted a good brand) were about £14 each

EDIT: So I need 9 R50s, 5 MR16s and 8 GU10s, the R50s are about £3, the rest at least a tenner a bulb, I can't afford £160 to kit my house out with bloody bulbs!