Bare soil under floorboards

macuser56

Hi all,

We have bare soil under many of the original floorboards of our house. We placed sheep's wool insulation inc. moisture barrier between these original floorboards and our new wooden floor which was laid, and there is no evidence of moisture or damp.

However, we are concerned about the lack of insulation. We have exterior vents- is there any way we could fill in under the old wooden floors on top of the soil through these vents?

I was thinking of cavity filled walls where foam is blown into them- is there anything similar for under the floorboards which could be filled through the external walls using these vents?

Thanks

slimjimmc

Not a good idea, you need that ventilation to prevent the floor joists rotting.

stapeler

I did similar about 15 years ago and could never control the cold coming through. Finally bit the bullet a few weeks back and ripped everything up, laid hardcore, 100mm kingspan insulation and concrete. Makes a massive difference and sorry I didn't do it years ago.
Was a bit upset ripping a perfectly good solid beach floor but needs must...

Martron

as slimjimm says you need the vents open. also i would be careful not to bridge the gap between the soil to you floorboards with insulation either.

PatcyMcl

Adding vents will only allow condensation more fuel from the room air.

Get a good dehumidifier to keep the room air dry and encourage evaporation.

macuser56

The vents are on the outside of the house and lead to the cavity beneath the floor boards of the house.

So I was thinking, is there a way to fill under the floor boards, on top of the soil, to make the house warmer?

GreeBo

You could try to fit rigid kingspan etc between the joists but above the soil level.The rigid insulation would have to be to a snug fit and you would probably be better off adding some supports for it to sit on but that should still allow for venting the joists while insulating the floor.

Whats the total depth and also the breakdown of gap, joists, etc?

ccsolar

stapeler wrote: »

I did similar about 15 years ago and could never control the cold coming through. Finally bit the bullet a few weeks back and ripped everything up, laid hardcore, 100mm kingspan insulation and concrete. Makes a massive difference and sorry I didn't do it years ago.
Was a bit upset ripping a perfectly good solid beach floor but needs must...

Hi
I did the same as stapeler a few years ago and it is the only job, you will be wasting money doing anything else, best to bite the bullet now and do the job right.


CC

slimjimmc

macuser56 wrote: »

The vents are on the outside of the house and lead to the cavity beneath the floor boards of the house.

So I was thinking, is there a way to fill under the floor boards, on top of the soil, to make the house warmer?

Those vents are supposed to be like that, they're designed to ensure a flow of air under the entire floor area. Filling up the space under the floor will prevent this airflow and allow damp to build up in and around the wood, perfect conditions for the fungus that causes "dry rot" or other the fungus that causes "wet rot". Dry rot can spread into masonary walls and other structures.

As the other posters have said, the ultimate solution is to take out the suspended wooden floor and replace with a solid concrete floor, properly damp-proofed and insulated.

stedeb

hi all
i have the same floorboards but concrete about a foot down maybe more
i was thinking of insulating underneath
can anyone give me an approx price of ripping out floor joists and insulating and concreting the full ground floor
thanks
ste

macuser56

thanks for the help on this

Mr Yellow

Bump

stapeler wrote: »

....Finally bit the bullet a few weeks back and ripped everything up, laid hardcore, 100mm kingspan insulation and concrete...

Anyone able to give an approx cost of doing this to a room measuring 15ft x 18ft?? Haven't even looked under the floor, I believe the gap is ~12inches deep or more!
I suppose concrete depth of 3inches be more than sufficient? Piping for rads is wall mounted, if that makes a difference!

Thanks,
Mr Y

looksee

We have a suspended floor over an approx 18" space. We don't have any issues with cold, except in one small, new area. We have just put in rigid insulation between the beams and even though the weather is not cold, it is possible to feel the difference in the temperature of the floor.

Any time the floors have been lifted, the underfloor area is fresh and dry and the 40 year old timbers are perfect. I think it is this good ventilation that gave us a low reading on a radon test, even though we are on a 'hot spot'.

Mr Yellow

Thanks looksee

Thing is, my place is old, solid walls in excess of 12inces so no insulation etc!
& to make it worse someone closed up the vents awhile back & this has caused some of the timbers to rot so floor needs repair / replacement soon enough! Thnking of just filling in the floor, once off job to last for years hopefully!

Congrats on low reading on a radon test BTW

Mr Y

Paddy McGinty

macuser56 wrote: »

we are concerned about the lack of insulation

Why?.. is the room particularly cold (compared to others?). There's nothing wrong with a suspended wooden floor such as you describe, providing it's vented (as it seems to be).

Put the palm of your hand flat against the wall just above the skirting board and do this at a couple of places on all 4 walls. You'll generally feel a marked difference with exterior walls, particularly on older houses if there's no cavity. I'd be looking at doors and windows before the floor and the radiator should ideally be at the coldest spot in the room (typically under a window if there is one and certainly on an exterior wall as opposed to interior wall). Hope this helps..no harm to have a few different suggestions anyway ;O)