Loft insulation and boarding

[Keefa]

Hi,

I am planning to insulate my loft as it currently has next to no insulation at all. It is an old house and the joists are only 4"x2". This would give me only 100mm of insulation. I do not need to board the whole area for storage so I could increase the insulation in the unboarded areas to say 250mm by laying insulation (mineral rock wool) across the joists, but I was wondering if there were any other insulation products which could give the same U-value but for a shallower depth.
Anyone know of such a product?

 

[Rich1]

Building regs are constantly changing and I think its is over 100mm now.

Anyway ther are several new products on the market that offer even better insulation. Whilst in Travis Perkins the other day I spotted some insulation that is about 1 cm thick and multi layered silver roll. It is supposed to be really simple to install, all you have to do is staple it to the roof rafters.

From whart I remember is is pricy but may be worth it in the long run.

 

[chappers]

that product is probably tri-iso super9 or possibbly 8 it has the same insulation performance as 9 and 8 inches of rockwool respectively and yes it is expensive.
you could use celotex or similar but its also expensive. you could use a 100mm dense rockwool wich comes in slabs