Tempo:
Another approach is to place the insulation above the sheathing, as is commonly done with low-slope roofs (Figure 27). Insulation exposed to the weather must be impermeable to moisture.
Polystyrene insulation is commonly used on the outside of roof sheathing and protected by the roofing membrane.
27 Insulation of a flat joist-type roof ceiling above the sheathing 40 mm (11⁄2 in.) crushed stone or gravel built-up roofing membrane type 4 expanded polystyrene insulation vapour barrier (only required for vapour permeable insulation) 9.5 mm (3⁄8 in.) plywood sheathing (roof not used as a walking deck) roof joist 12.7 mm (1⁄2 in.) gypsum board ceiling
SUSTAINABLE HOUSING INSIGHT Healthy Indoor Environment
Batt and loose fill insulations release airborne particles. As a result, masks and gloves should be worn when handling or disturbing these materials. Polystyrene and polyisocyanurate insulation must be protected against exposure to fire. Controlling the movement and condensation of water vapour with a vapour barrier and sufficient insulation reduces the likelihood of mold problems. Reducing air leakage with an air barrier system also reduces the likelihood of moisture condensing in the walls or roof and causing decay and mold growth.
Controlled mechanical ventilation can provide better quality air to the house than uncontrolled ventilation through air leakage.
Energy Efficiency
Reducing air leakage and using high levels of insulation save heating and cooling energy. Consider providing insulation levels higher than those required by the building code to increase the overall energy efficiency of the house.
Resource Efficiency
Where possible, use insulation materials made from industrial by-products or recycled waste such as most glass, mineral fibre and cellulose insulations.
Polystyrene insulation is commonly used on the outside of roof sheathing and protected by the roofing membrane.
27 Insulation of a flat joist-type roof ceiling above the sheathing 40 mm (11⁄2 in.) crushed stone or gravel built-up roofing membrane type 4 expanded polystyrene insulation vapour barrier (only required for vapour permeable insulation) 9.5 mm (3⁄8 in.) plywood sheathing (roof not used as a walking deck) roof joist 12.7 mm (1⁄2 in.) gypsum board ceiling
SUSTAINABLE HOUSING INSIGHT Healthy Indoor Environment
Batt and loose fill insulations release airborne particles. As a result, masks and gloves should be worn when handling or disturbing these materials. Polystyrene and polyisocyanurate insulation must be protected against exposure to fire. Controlling the movement and condensation of water vapour with a vapour barrier and sufficient insulation reduces the likelihood of mold problems. Reducing air leakage with an air barrier system also reduces the likelihood of moisture condensing in the walls or roof and causing decay and mold growth.
Controlled mechanical ventilation can provide better quality air to the house than uncontrolled ventilation through air leakage.
Energy Efficiency
Reducing air leakage and using high levels of insulation save heating and cooling energy. Consider providing insulation levels higher than those required by the building code to increase the overall energy efficiency of the house.
Resource Efficiency
Where possible, use insulation materials made from industrial by-products or recycled waste such as most glass, mineral fibre and cellulose insulations.
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