Wall insulation installation instructions

These instructions should be read in conjunction with local standards AS 3999 or NZS 4246 and all applicable local, state and federal building regulations.
Before you start installing, please make sure you are familiar with our Health and Safety Message.
Ensure that you use tools and equipment that are suitable for the intended application. This will include suitable safety equipment.

Do not start work until the site is safe!

Assess the wall condition and structure together with the method of installation you are to use based on the appropriate requirements established in the building code, site assessment and or plans provided. Installation must be completed to the requirements of relevant standard: AS3999:1992 or NZS4246:2006.



  • Determine the most suitable product for your project. Walls can be insulated using rolls or
  • Insulation is available in varying widths and thicknesses to suit most framing spaces. Please
    check Knauf Insulation’s product guide for the most suitable product for your application.
  • To calculate the number of packs needed, determine the area (m²) to be insulated by
    multiplying the length by the width or wall height. The number of m² of insulation material is
    clearly marked on each pack. Divide the total area to be insulated by the m² in a pack to
    determine the number of packs required (don’t forget to round up to the nearest whole pack).
  • Allowances should be made for areas that are unable to be insulated.
    STEP 2

  • Don’t take the insulation out of the packages until you’re in position and ready to install.
  • Before installation check that the product selected matches the specification
  • Ensure that the insulation has lofted to the nominal thickness, if required, gently agitate the
    insulation by ‘bouncing’ it on its side until it recovers to thickness stated on the label.
  • Where installing around wall lights or heat sources consult the appliance manufacturer’s
    instructions for appropriate clearances. Additional guidance is provided in AS 3999 and NZS4246.


  • When installing insulation between framing members, ensure that you achieve a snug fit
    avoiding any gaps, tucks and folds.
  • It is recommended that you select products that have the same thickness as the cavity. In
    circumstances where the cavity is deeper than the product selected, adequate support must be
  • Make sure insulation fits snugly against top and bottom wall plates. The front face of the
    segment should be flush with the inside face of the framing
  • For Metal frame walls, install insulation according to the relevant building code. Friction fit one side of the segment into the metal C-channel and butt the other edge against the metal stud.
    Install insulation to cover the full height of the wall including spandrel areas.
  • Use off cuts to insulate small and hard to fit areas


  • Attention to detail is very important. Make sure all areas are insulated, behind electrical
    outlets, plumbing and services
  • Seal all penetrations in exterior walls with insulation or foam sealants.


  • Complete a final check of the installation ensuring all areas have been insulated and that you
    have an even and consistent layer of insulation.
  • Finish your project by removing all packaging and disposing of all rubbish and excess
    insulation responsibly.

For more installation advice watch our wall install video here and read our electrical safety information here before doing any work in the walls.