improving insulation, in converted attic?

[Simon]

What is the easiest way to improve loft insulation, where the loft has been converted to a room.

Is there a simpler way than removing the plasterboard, inserting rockwool insulation, and reboarding?

[Ian Stirling]

Leaving the plasterboard there, covering it with 50mm kingspan, put new plasterboard over it. This is of course both more expensive, and will take up more room.

[Phil L]

without spending a fortune on rigid insulation, you have little choice other than to do as above...do you mean between house and loft or between loft and outside?

[Hugo Nebula]

On Fri, 15 Dec 2006 15:37:34 GMT, a particular chimpanzee named "Simon" randomly hit the keyboard and produced:

Aside from the fact that you shouldn't remove the plasterboard, insert Rockwool and reboard. You need to maintain a ventilation space above the insulation of 50mm; Rockwool between the rafters is a relatively poor insulator; and most illegally converted lofts will have had the plasterboard fixed directly under the 3" or 4" rafters, meaning that you probably only have enough space for 25mm-50mm insulation between.

The best way to improve the insulation is to take off all the plasterboard from the walls, take up the floor, remove any stairs, fit a loft hatch, and then put about 300mm Rockwool between the ceiling joists. This will also have the advantage of removing a death trap.

[Ian Stirling]

With a suitable escape window, and fire alarms, I don't really see an issue.

If it was me, I'd be looking at 25mm airgap, 50-75mm fiberglass against the rafters, and lots of ventilation at the ridge and bottom - 10mm gap or so. Then 25mm kingspan under that, properly taped up to make a vapour barrier.

If I was being cheap, 100-120mm of fiberglass, with slices of 50mm kingspan along the joists, to extend them out, reduce their heat leaks, and provide extra space for cheap fiberglass, then plasterboard, again with a proper vapour barrier.