Application  >  Roof - Above rafter insulation

Roof - Above Rafter insulation

Natural wood fibre sheathing & sarking insulation boards are installed over the roof rafters / trusses to provide an insulating and water protective layer against the elements.


  • Immediate weathering protection – up to 12 weeks
  • Hydrophobic - repels water (acts as a sarking board)
  • Excellent insulating properties reducing thermal bridging in the roof elements
  • Vapour open allowing trapped moisture within the roof component to escape
  • Excellent soundproofing qualities
  • Tongue & Groove on all 4 sides preventing unwanted air drafts
  • Prevents dust blowing into the building envelope
  • Provides structural strength to the roofing element
  • Good fire resistant qualities
  • Easy to cut & install 
  • Save $ on a duplicate membrane...
Installation process is easy
Check out this video of a rigid insulation board being installed over rafters

Installed on pitched roofs.
The natural woodfibre boards can be installed on any pitched roof.  


No additional waterproof measures are necessary for pitches over 18 degrees.

Installed on flat roofs
Boards with a straight edge profile are available with thicknesses of  20mm  to 240mm.

Water repellent boards

The wood fibre insulation boards are hydrophobic meaning they repel water.

Boards can be left unfinished for several months allowing you to get your house secured from the elements

Boards with integrated weatherproof membrane &
self-adhesive strip also available

For low pitched roofs with increased requirements for rain protection.

Typical Roof detail  

A double batten system is used to fix the boards to the rafters and for the fixing of the roof cladding (Roof tiles or metal sheets). The space between the battens provide an air gap for air flow and for the evaporation of any trapped humidity in the roof envelope.
Below are some generic details for tiled roofs. However same principal applies for roofs with metal sheets.

Rigid insulation board
specifications & pricing

Need more technical information ?

You can download the Installation Guides to the Rigid insulating  Sheathing & Sarking boards;  as well as the Product Data Sheet at our Downloads section.

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Our natural wood fibre insulation partner: Steico


Benefits of Natural Wood Fibre Insulation

Excellent summer heat protection

Excellent winter protection 

Weather tight and breathable

Good sound protection

Excellent fire protection

Easy to install with regular tools

© 2020 Insulate Naturally 

Insulate Naturally is an Australian supplier of truly green building & insulation materials.
We specialise in natural, ecological, and healthy wood fibre insulation products for the home. 
We deliver throughout Australia: NSW, Victoria, Queensland, ACT (Canberra), WA, SA, Tasmania.
We can also ship to New Zealand.