What type of insulation for you?
How do we achieve an insulation requirement in relation to a roof? This can be achieved by manufactured materials and an enclosed air space between the underside of the roof cladding and the ceiling below. Please note that Sisalation is a requirement for condensation requirements. Additional to this the reflective value is rated as R1.0
The Insulation types are as listed below:
- Sheep wool
- Aluminium foil
- Foil board
The most common on the market is fibreglass and polyethylene bonded to aluminium foil paper. These products are manufactured with various ratings. These ratings are only achieved by proper installation of the product.
The way fiberglass achieves it rating is by how much air volume it can absorb in its thickness. However if the insulation is not allowed to recover to the required thickness the rating of the insulation can be minimised by as much as 90%. To achieve the required thickness of this type of bulk insulation you can install spacers between the underside of the cladding and the fixing point and or install directly onto the ceiling cavity.
The polyethylene achieves its rating by the product being installed with spacers between the under side of the fixing points to create a required air gap.
When choosing insulation another item on the agenda is acoustic capabilities. When metal is used for roofing materials heavy rain can create a lot of noise. When choosing insulation for an area that will house people like a gymnasium or high-rise warehouse outlet one must place some consideration towards the acoustic rating (if any) of the insulation being used. Some insulation on the market does not rate any acoustic value at all.
The same ideology applies to wall cladding insulation / acoustic requirements as well.
Additional to the above there are combination products that have a metal skin on the external sides and an internal core that provides insulation. Again the thickness of the insulation supplies you the rating for the BCA code.
Photos below are where insulation has been installed under a roof where sisalation was not installed, hence water is present due to the due point effect. Condensation forming under the roof sheets has dripped off and saturated the insulation below.