Insulation installation and air tightness

Last updated: 15 December 2021
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Insulation performance is highly dependent on the way it’s installed. The following 3 videos provide useful information for trades and supervisors on how to correctly install insulation and seal a building, with a focus on identifying and treating common problem areas in residential construction.

Benefits of proper insulation

  1. Good thermal performance – insulation integrity and low air leakage makes homes warmer in winter and cooler in summer.
  2. Indoor environments that are free of draughts – cold draughts can be felt through gaps in the building’s shell and make for uncomfortable living conditions. It can be difficult and costly to keep draughty homes comfortable.
  3. Low risk of condensation – areas that are missing insulation or contain thermal bridges can cause surfaces to be cooler than their surroundings. This can cause condensation, which could result in mould and mildew. Mould and mildew pose a significant risk to the health of the home’s occupants.
  4. Lower energy bills – homes that are well sealed and insulated are easier to heat and cool, as there is a lower rate of air-change with the outside. This means less reliance on heating and cooling systems which reduces energy use and energy bills.
  5. Less wear and tear on mechanical systems – homes that have less need for heating and cooling cause less wear and tear on mechanical heating and cooling systems, saving money for the homeowner and reducing embodied energy.

Although there is no current code requiring builders to verify the performance of a home’s thermal envelope, an as-built verification (ABV) assessment can be completed to guarantee that a home is constructed to meet the design specification or specified design standard. Learn more about this in The ins and outs of ABV technical article.

Insulation installation at lock up stage

This video addresses the installation of insulation in a home at the building wrap and insulation stages. It demonstrates how to correctly install insulation around key problem areas including:

  • external wall junctions and lintels
  • bulkheads and cathedral ceilings
  • skylights
  • services platforms
  • perimeter of ceilings and the roof
  • suspended floors.

Key learnings from the video

Building air tightness at the plaster and fixing stage

This video addresses the sealing requirements at the end of insulation or during plaster stage of a standard home. It demonstrates how to create a continuous barrier against unwanted draughts, highlighting how to treat key problem areas such as:

  • at the junction of walls, floors and ceilings
  • around bulkheads and on top of cabinetry
  • ducted heating and cooling return air plenums
  • around windows and doors
  • internal cavity slider doors.

The video is also relevant for retrofitting a new home to be more efficient when installing new joinery for a kitchen or a bathroom.

Key learnings from the video

Building air tightness at the practical completion stage

This video addresses ventilation, air tightness and insulation issues for plumbing, electrical and joinery trades services at the practical completion stage of construction. It demonstrates how to create a continuous barrier against unwanted draughts, highlighting how to treat key problem areas such as:

  • around penetrations for plumbing
  • around joinery elements
  • around ceiling mounted elements such as downlights and exhaust fans.

This video is relevant when retrofitting an existing home to be more efficient.

Key learnings from the video