Underfloor insulation

[jasramsden]

Hi all,

I will be replacing my downstairs boards on a suspended timber floor and I would like to know if anyone has any experience in insulating under the boards before I lay them down.

I was considering stapling chicken wire or similar to the underside of the joist and then filing in with rockwool before laying the board back down.

Jason.

 

[RickyLee53]

Hi all,

I will be replacing my downstairs boards on a suspended timber floor and I would like to know if anyone has any experience in insulating under the boards before I lay them down.

I was considering stapling chicken wire or similar to the underside of the joist and then filing in with rockwool before laying the board back down.

Jason.

Hello,

I did exactly the same, but used pond mesh, (cheapest) I used 200mm rockwool. Packed tightly around the edges, where you lose most heat. I think it made a big difference, although hard to tell exactly because it was i prep for underfloor heating.

 

[goody2b]

About 15 years ago I fitted loft insulation underneath our ground floor using the plastic netting used in gardening..I noticed a small difference

When I retro fitted underfloor heating to the whole of my ground floor using the harder insulation boards and noticed quite a big difference. If you can physically get underneath your floor , cut the board to fit(wear goggles, it is hideous stuff!) the channels and then fill the gaps with any type of sealant you have knocking around. In our case , because we lived in what used to be a draughty 1930's house, with using the loft type insulation there are too many gaps. I think I used Celotex that a friendly builder had cut too short!

Good luck

 

[RickyLee53]

I used Kingspan on my vaulted ceilings. I filled the gaps with expanding foam. Worked great for cutting out drafts.

About 15 years ago I fitted loft insulation underneath our ground floor using the plastic netting used in gardening..I noticed a small difference

When I retro fitted underfloor heating to the whole of my ground floor using the harder insulation boards and noticed quite a big difference. If you can physically get underneath your floor , cut the board to fit(wear goggles, it is hideous stuff!) the channels and then fill the gaps with any type of sealant you have knocking around. In our case , because we lived in what used to be a draughty 1930's house, with using the loft type insulation there are too many gaps. I think I used Celotex that a friendly builder had cut too short!

Good luck

 

[muggles]

Celotex / Kingspan type stuff is going to be much more effective than Rockwool

 

[Agile]

The problem seems to be mainly draughts.

So if you used plastic sheet under the rockwool then that might get over all the problems.

Some would say there may be some ventilation or condensation issues though.

Tony

 

[goody2b]

When I was installing my underfloor heating , as I was totally sealing in the heat, I was advised to ensure that there was adequate ventilation to avoid the possibility of condensation forming underneath the insulation and maybe transferring across to the timbers and then causing them to rot. Luckily i had already got air bricks under the whole house.