Best place for insulation

[dllive]

Hi,
Im getting underfloor heating in my cottage and want to add new insulation in loft. Some questions:

1) Wheres the cheapest place for loft insulation?
2) Is it 300mm for building regs?
3) I think the insulation thats in there has been there for about 40 years. Should I replace it or just add new stuff over the top of it?

Many thanks

 

[dllive]

Also, Does anyone know any grant scheme in the South West for this (that isnt means-tested)?

 

[oldbutnotdead]

1) Varies from week to week. Work out how much you need and then check the DIY sheds and local suppliers as well as online.
2) 300mm will be fine, more than that isn't usually cost effective. Leave a gap at the eaves.
3) If it has been crushed or is disintegrating and full of dust and dead things then get rid (wear a dustmask and good gloves/overalls, if it is fibreglass it is really itchy on your skin)

Grant- if you're on state pension or any sort of benefit then yes, otherwise no.