Loft insulation advice

[DIYNovice1979]

Hi,
My loft is mostly boarded and has insulation under the boarding to a depth of 10cm. The house feels chilly in winter and I'd like to improve insulation. The first thing I want to do is insulate the section without boards (see pics below). It looks like the previous owners did some work and left this section uninsulated as the old insulation is just lying on the side. I'm planning on getting some mineral wool insulation (20cm) and putting that in place (I'll throw the old stuff away).

1. Do I need to be careful about avoiding placing insulation on electrical cables?
2. Eventually I'd like to improve all the insulation, but I believe I need to raise the level of the boards to get appropriate insulation underneath, does anyone have advice on the best way to do this?

Thanks in advance

 

[RepairingDave]

1. Do I need to be careful about avoiding placing insulation on electrical cables?
2. Eventually I'd like to improve all the insulation, but I believe I need to raise the level of the boards to get appropriate insulation underneath, does anyone have advice on the best way to do this?

As far as I know there shouldn't be a problem as long as the weight of the insulation isn't causing stress on the cables.

There are legs for sale to raise the level of the loft boards, or you can add joists in the opposite direction, or a combination of both.

 

[RandomGrinch]

1. Do I need to be careful about avoiding placing insulation on electrical cables?

Yes, you do need to be careful with insulation covering cables.
Cables related to anything other than lighting circuits, may need their over-current protection derated, to help avoid overheating in the cable (and a possible fire risk), if they were buried under insulation.
To avoid derating, these type of power circuits should have the cables run above the insulation.

Lighting circuit cables, that are protected by a 6A RCD, usually run at such minimal currents, that there is negligible heating effect, even when fully buried under the insulation.

Of greater concern though, are all the down lights. These should be protected by insulation covers - there is a serious risk of overheating if downlights are directly covered in insulation - especially if any of the bulbs are still halogen.
A cover may be as simple as an upturned terracotta plant pot.

If any of those down lights are in a bathroom, it may be worth investing in a proper cover, that incorporates a vapour barrier - this will help avoid water vapour from the bathroom escaping into the loft space and causing damaging condensation.