Loft insulation, what materials should I use

[Yukster]

I cleared my loft which was previously insulated with rock wool (covered with a think layer of black dust) between the joists. There wasn't any insulation fitted between the rafters. Can you please offer advice re what insulation material I should use?

I just came across http://www.boilergrants.info/ and http://www.keepwarm.co.uk/ who offer free lost insulation. Is that kosher or is it some sort of a scam?!

Thanks for your advice

 

[PrenticeBoyofDerry]

The grants are kosher but there are generally some condition that apply, you would have to check them out.
Mineral wool is as good as anything to use as thermal insulation.
Building Regs now recommend a minimum of 270mm layer/layers.
But be aware that thermal insulation if installed where electric cables are present, could prevent heat evenly dissipating from the cables, therefore the current carrying capacity of these cables is reduced. So you may have to bring them above the insulation layers.
Generally lighting circuits on 5A or 6A fuse/breakers are okay, but power circuits such as sockets, showers, cookers, heating etc, will require either moving above insulation or upgrading.

 

[Yukster]

The grants are kosher but there are generally some condition that apply, you would have to check them out.
Mineral wool is as good as anything to use as thermal insulation.
Building Regs now recommend a minimum of 270mm layer/layers.
But be aware that thermal insulation if installed where electric cables are present, could prevent heat evenly dissipating from the cables, therefore the current carrying capacity of these cables is reduced. So you may have to bring them above the insulation layers.
Generally lighting circuits on 5A or 6A fuse/breakers are okay, but power circuits such as sockets, showers, cookers, heating etc, will require either moving above insulation or upgrading.

Thanks. What is the most effective yet not too costly way of laying a floor once insulation has been done. Should I use tongue and groove chipboard? and if so what retailer sells a good one?

 

[tony1851]

If you put the recommended thickness of fibreglass insulation in your loft, you will not be able to board it out in the ususal way.
You will need to build up some sort of framework to support the new boards clear of the insulation.
Don't apply any insulation to the rafters.

 

[PrenticeBoyofDerry]

What is the most effective yet not too costly way of laying a floor once insulation has been done. Should I use tongue and groove chipboard? and if so what retailer sells a good one?

To get the recommended layer of insulation in, it is likely that the areas that are to be boarded, will require raising. This is done by fitting timbers perpendicular to your existing joists, these can be spaced suitable so your loft boards fit with the minimum of cuts. Spacing at 400mm centers is usually best practice. T&G boards will offer better bonding structure to the floor.