Insulation Attic Upgrading
Heat Loss
In our climate with relatively long heating seasons anywhere between 10% and 15% of a buildings heat loss can occur through the ceiling into the attic. Half (50%) of this heat loss is by conduction, i.e. heat flowing through the insulation and framing. Air leakage through openings and cracks account for the remaining 50% of heat loss. High insulation levels for attics are recommended as these areas are usually easily accessible and with few obstructions.
Factors For Insulating Attics
There are four main factors to be considered when insulating new attics or roofs:
- Framing structures must allow for adequate insulation plus room for ventilation above the insulation where possible
- Framing should allow for the full thickness of insulation to be applied over the exterior wall top plates
- The insulated ceilings need a properly installed air/vapour barrier under the insulation which must be sealed airtight
- Proper ventilation is required to remove any moisture build-up and help to reduce summer heat build-up.
Installing Insulation
The most common materials used in new construction attics are batt/blanket types or loose fill insulation. In some circumstances it's a good idea to use a combination of insulation types. If there are a lot of obstructions above the joists, such as with a truss roof, it may be easiest to put batt insulation into the joist spaces and then use loose fill to create a monolithic blanket of insulation. If some spaces are irregular or obstructed, it may be easiest to use loose fill.