cold floorboards bbbrrrr!

happyhero

Hi I have a lounge which has your typical approx. 6inch wide floorboards and there are airbricks in the front of the house and back. We were getting terrible drafts through the cracks , so one year I decided to silicon the gaps and around the skirting edge. We also put down a rug but it is still not great especially when its really cold like now.

You end up not wanting to put your feet down as even the rug is cold and if I go feeling around the floor I can find areas where some drafts are still getting through. We also have a brass floor vent which has a slide open and close thing on it which I find pretty rubbishy for stopping drafts and in any case we have a gas coal effect fire in that lounge so don't think I want to stop all air getting in.

Read up on a few ideas but no one seems to have suggested this

Airtec Double Insulation 1.5m x 25m Screwfix item number 50913

I could lift the floorboards and staple this to the rafters and then replace the floor but would it be ok?

ie would I get sweating problems or cause any lack of airflow problems? Or can anyone see some other problem with it?

I understand about keeping the airflow in an attic when insulating and how to maintain it and applying the same sort of idea to this task, this method seems ok but am I missing anything or would you not use that and go for something else instead such as Kingspan etc. Kingspan seems good stuff but this Airtec stuff could almost create a unbroken sheet across the whole floor if you tape the joints.

Any help or info appreciated.

ormus

http://www.wickes.co.uk/invt/161189
i would use summat like this. then either replace the floorboards or use mdf/CB type flooring.
or you could just place rockwool (or wall batts?) inside the joist and refloor as required. you would need some sort of rustproof brackets to hold up the insulation.
the void underneath should be ventilated with ie airbricks from outside.

always keep any airbrick open when using a gas fire.

Canucklehead

Good evening: Don't use Airtec as floor insulation....see my previous post.. http://forums.moneysavingexpert.com/showpost.html?p=6275935&postcount=7

HTH

Canucklehead

happyhero

ormus wrote: »

http://www.wickes.co.uk/invt/161189
i would use summat like this. then either replace the floorboards or use mdf/CB type flooring.
or you could just place rockwool (or wall batts?) inside the joist and refloor as required. you would need some sort of rustproof brackets to hold up the insulation.
the void underneath should be ventilated with ie airbricks from outside.

always keep any airbrick open when using a gas fire.

What is mdf/cb I am struggling to find it on the web?

Also those slabs from Wickes are they full of fibreglass, ie itchy stuff?

And lastly I suppose you just cut them to fit as tight as you can?

happyhero

Sorry to keep on about this but I fancied the Airtec stuff as it could have given me a complete skin with taped joints to completely stop any drafts getting through apart from where I wanted, ie the air vent in the floor for the fireplace we have, but Canucklehead has pointed out it is no good for this job, so is there some other thin sheet that is not to expensive that I could use to achieve this still over the joists/slabs that would not cause any condensation problems?

I know it might seem overkill but you should come and feel my lounge floor this time of year and then you would know why I want to be so thorough.

Also having used Celotex before when helping some builders convert my attic in the past and knowing how nice it is to work with, I am tempted to use this http://www.celotex.co.uk/floors/suspended.php
instead of the slabs, no itchyness and nice to cut, what do you think?

It is designed for the job but I am unsure about the underside as I have heard it said that you should not have foil on the cold side (i.e. dont put any membraine/foil under the joists) which this appears to have , ie the underside. http://www.celotex.co.uk/downloads/SuspendedTimberFloors.pdf
I suppose it is ok here as this has been designed for the job.
What do you guys reckon?

LuciferTDark

Keep your socks on, that's what I do

hulkiebear

Hi, I'm currently doing the same thing in my kitchen, but I'm just going to use 50mm polystyrene from wickes, cut to fit tight between the joists, then over the top (before I lay the boards back down), I'll put a vapour memebrane, this will stop any draughts and moisture getting to the flooring layed over the top. I can't see any problem, as the joists underneath will have plenty of ventelation from the void beneath and the boards will have ventelation from above. I suppose the only issue might be if a substatial amount of water or liquid were spilt on top and had no where to drain before causing damage.

happyhero

hulkiebear wrote: »

Hi, I'm currently doing the same thing in my kitchen, but I'm just going to use 50mm polystyrene from wickes, cut to fit tight between the joists, then over the top (before I lay the boards back down), I'll put a vapour memebrane, this will stop any draughts and moisture getting to the flooring layed over the top. I can't see any problem, as the joists underneath will have plenty of ventelation from the void beneath and the boards will have ventelation from above. I suppose the only issue might be if a substatial amount of water or liquid were spilt on top and had no where to drain before causing damage.

I wonder about the membrane although I fancy something similar to give a complete screen against any draughts as when I read loads more and went a bit deeper on the subject , they talk about breather membranes. I know you have to be very carefull how you insulate not to produce any sweating which would rot things. I like the idea of a sheet as well as the insulation also as you cannot garantee a perfect cut of the insulater eg the polystyrene or what ever you use over a full floor area to stop any draughts etc.

With the insulator I keep reading that it should be tight against the floor board, ie no air gaps above it, not quite sure why this is. How were you thinking of supporting it so that it does not fall away ever?

hulkiebear

I'm using 2ft by 8ft sheets of polystyrene and I was going to cut 2 ft sections to fit perfectly between the joists, I realise that the pieces will have to stay perfectly parallel so each piece has a tight fit to the next one, but I thought it would be alot easier(end up with a better cut) than trying to cut an 8 foot piece to fit well. Also it will produce very little waste! I have cut a couple of pieces and cut them about 2-3 over size, then wedge them into place(about 1-2mm proud, so the boards will tighten them down and there will be no air gap). This seems to work fine, but I was a little worried that over time, they may shrink or something and drop down, so I'm just going to use 4, 2" nails, hammered in the joist about 50% in each cornerabout 4 inchs in from each the end and just low enough for the Polysyrene to sit on after being pressed in.

I was a little worried about sweating and condensation with a membrane, but thinking about it, it would be the same as using lino on top.

hope that all made sense!
HB

Inactive

What is wrong with carpet?, my carpeted floor, with it's really thick underlay is really cosy.;)