Under-floor insulation

[jal]

(I know it's a bit late but) I'm thinking about insulating the ground floor. Any comments? I'm thinking:

1. buy some of that stuff which comes as fairly rigid fibre slabs (3' by

14"?? -- we used it for our new extension loft, 15 years ago: can't remember the name - much handier than glassfibre rolls)).

1. go under the floor, and strap this stuff up [somehow] between the joists.

2. do I just "wall in" all the microbore CH pipes, electric cabling etc, or should I take steps to protect them/leave them free?

1. This is a 1962-built semi-detached.

2. (I think I dare make it public here, and it may actually be relevant): I turn 60 before long (I know, I know! Hard to believe, lads but it's true :-< )

1. any other points? My main Q to this group is No.3 above.

The main object is to feel warmer: "paying for itself" is not so much of a consideration. This does not mean I am rich: it means I'm sick of feeling cold (and of shelling out my hard-earned to foreign energy conglomerates who were handed our national energy industry a few years ago).

Cheers John

[Steve]

Plastic garden netting is often recommended for this.

The electric cabling should not be covered in the insulating material as the current carrying rating of the cable would be reduced. The pipes should be well lagged under the floor anyhow so I don't think any extra insulation around them would do any harm.

Steve

[dom]

I'll have a go - I'm sure others will add more detail/corrections:

1. Slab or roll insulation sounds fine. Sounds like you have good underfloor access, so blocking necessary air circulation shouldn't be an issue. AIUI retrofit floor insulation is some way down the "most benefit" priority list after tanks & pipework / ceiling & roof / walls / windows & doors / other draft sources though.

1. You could try stapling netting/chicken wire to the underside of the joists.

2. CH pipes should be lagged anyway, so extra won't do any harm. Electrical cables need to dissipate heat, so they should remain as they are. Pvc cabling shouldn't come into contact with polystyrene, but sounds like you will use glass wool.

1. Repeat after me, "I'm a pensioner, gi'us a discount!"

[mail]

Dear John As one who turned that some time ago, and who has had the same problem.. IF you have room to fit under the void the problem is easy Get either sheets of TP10 Kingspan or the equivalent 600 x 1200 x 50 smaller cavity wall or roof insulation board and nail it to the underside of the joists using the stainless steel "nails" (square twisted) and 2" round plastic washer/ fixings used by Kingspan to put on the EXTERIOR insulation before rendering. This will hold it in place and provide a continuous layer under the joists. If no room to get under and nail then back to netting Chris

[Matty F]

If using chicken wire or aluminium foil or anything conducting, be very careful not to staple the wiring. I've heard of three people who died by touching foil that was stapled to wiring.