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Improving insulation in sloped upstairs ceiling
I have no loft space, just sloped ceilings with approx 100mm of purlins exposed - These ceilings were done in 2005, I think, and do contain some kingspan but it is quite thin. Do I need to take the ceilings down or can I just add more kingspan and plasterboard between the purlins using batons for support? If so, how thick should kingspan, plasterboard and and batons be? Thank you.
you must leave a 25mm air gap between the kingspan and the felt or breathable membrane. if it was done properly you probably have the maximium depth of kingspan required.
Answered 10th Nov 2012
you will need to take off the plasterboards and de nail the rafters coming down. then you will need 150mm kingspan in total. leaving a 50mm air gap between insulation and felt. if you can put 100mm between rafters and 50mm across with counter battens to screw the plaster boards into make sure you use foil backed plaster boards as well. its good practice to tape all the insulation joints as well.
Answered 11th Nov 2012