Insulation between floor joists

[overlander matt]

The floor boards are up in two rooms and the heating pipework and new cables are nearly in. I would like to insulate between the floor joists but can see a couple of different approaches will be needed. In one room the floor joists are reasonably new 6" timber and an insulation board could be used but in the other they are very old with irregular shapes and spacings. I wondered whether an roll-based insulation material might work better in this case. In a previous house, I used chicken wire to support the insulation material but did not use any membrane which might well have been a mistake...

What would be a suitable membrane to use and is it best installed above or below the insulation? Any suggestions would be very welcome.

Thanks.

 

[paulc]

Ground floor or first floor ?

As I "do" each room in my house, I'm taking the ceiling down and putting fibreglass insulation in the void between joists. The theory is that it will cut down on the draughts and provide a bit of noise insulation. Not too sure about the noise, but it has certainly improved the warmth in the rooms I've done so far.

On the ground floor, if I had the space, I'd have used chicken wire to support fibreglass insulation and no vapour barrier. Unfortunately, my joists & floorboards do not lend themselves to a decent amount of insulation. I don't have sufficient space over the sleeper walls either, so under floor ventilation would have been severely compromised.

 

[overlander matt]

I've finally got round to digging out the void below the floor boards and improving the sleeper walls to allow for more air movement below the floor boards. I have my doubts about how much movement there will be when there are no airbricks/vents fitted. On the plus side the sub floor is pretty dry and the house has no signs of damp so I will look to get on with the insulation...

I'm still undecided about chicken wire or a membrane between the joists to support the insulation material. I've gone with a wool based product on this occasion in this room as the floor joists are more original than elsewhere. Does anyone have any thoughts about the right means to support the insulation?

Thanks in advance.

Matt

 

[agbagb]

Ground floor with ventilated space underneath? I use breathable, roofing membrane, so much easier than chicken wire holding up rock wool type insulation.

I've only used chicken wire when it's needed for fire proofing reasons, 30 or 60 mins, with the mineral wool slabs so they dont fall out.

You mention new wiring going in, don't have the insulation around the cables unless the loading on the circuit has been de-rated, cables need to be able to lose heat and need to be specified for the full run, check with a sparky if they are surrounded by insulation at any point!