Help regarding underfloor insulation for archway!

clutterbug_2

Hi,

I'm having a bit of difficulty in finding out what we can do to make our spare room a bit warmer.

Let me explain: our spare room and bathroom sit ontop of nothing - and by that I mean that there is no room or building below them, they are above an opening between two houses, cars drive below them to get behind our house!!

Because of this there isn't any warms from below and we get a strong breeze coming up through the floorboards! We've solved that problem in the bathroom by putting new floorboards above the old ones, and it seems to be keeping quite warm - probably because its small.

But when it comes to the bedroom, we want to put a nice carpet (and very thick underlay!) down, but I still think as its such a big room, its going to be cold. Ideally we'd like to put insulation inbetween the outside wood and the inside floorboards - yes, thats all there is!

Trouble is, we can't get the floorboards up because they pretty much run the full length of the archway and under the bathroom (stud) wall.

I've seen them pumping insulation into cavity walls, is it possible to do this inbetween the floorboards?

Any other ideas?

Thanks

MX5huggy

No reason why not, drill a few holes and pump the stuff in. Just need to consider what insulation you want, Polystyrene beads, pulped paper, rock wool fibre? you also want to seal all the drafts out. Best even if you can do this out the outside surface.

olias

Personally I wouldn't reccommend it. You may have services under the floorboards - wiring, plumbing etc - that you may need to access in the future. Also, if there are gaps to outside that are big enough to feel a noticable breeze, then if you don't find and plug all of them, then your pumped insulation will escape all over the place. Lastly, to get insulation in between every joist, would entail drilling a sizeable hole (about an inch or 2 accross) through the floorboards between each rafter!) It is not a difficult job to cut through an in-situ floorboard - just google and there is loads of advice - for example this:

http://www.ultimatehandyman.co.uk/forum1/lifting-floorboards-t6546.html

Once you have lifted the boards, I would recommend sealing every gap to outside that you can find, and then insulate between the joists using rigid insulation eg celotex/kingspan. Make sure this is tight between each joist to avoid any gaps and tape any seams.

HTH

Olias

clutterbug_2

Thank you all for your replies.

Unfortunately without an awful lot of mess and work its not going to be possible to take the floorboards up, and I never considered sealing all the holes in the space below. At 20m square+ its a big area thats not easy to get to as its high and on uneven ground underneath.

So, I think its going to be a case of sealing between the floorboards (there's not wiring or pipework under the boards as it all comes down into the room) and then getting the thickest underlay possible.

Thank you again for all your help, it is much appreciated.