Conservation of Energy ~ this can be achieved in two ways:
1. Cold Deck † insulation is placed on the ceiling lining, between
joists. See page 448 for details. A metallized polyester lined
plasterboard ceiling functions as a vapour control layer, with
a minimum 50 mm air circulation space between insulation and
decking. The air space corresponds with eaves vents and both
provisions will prevent moisture build-up, condensation and
possible decay of timber.
- (a) Warm Deck † rigid* insulation is placed below the
waterproof covering and above the roof decking. The insulation
must be sufficient to maintain the vapour control layer and roof
members at a temperature above dewpoint, as this type of roof
does not require ventilation.
(b) Inverted Warm Deck † rigid* insulation is positioned above the
waterproof covering. The insulation must be unaffected by
water and capable of receiving a stone dressing or ceramic
pavings.
* Resin bonded mineral fibre roof boards, expanded polystyrene or
polyurethane slabs.
Typical Warm Deck Details ~
Timber Flat Roofs---Thermal Insulation