Factors That Can Make Underfloor Insulation Installation Expensive

Table of Contents

When planning for underfloor insulation installation, several factors can contribute to increased costs. Here are the main aspects to consider:

Type and Quality of Insulation Material

High-Quality Materials – Premium materials like polyester insulation, which is durable, non-allergenic, and resistant to moisture, tend to be more expensive than standard options like fibreglass. Higher R-value insulation provides better thermal performance but comes at a higher price, ensuring better resistance to heat flow and improved energy efficiency.

Area to Be Insulated

Size of the Space – Larger underfloor areas require more insulation material and labour, naturally increasing costs.

Complex Layouts: Homes with complex floor plans, with bulk heads and encased sub-floors make it difficult to navigate under the floor. 
Unusual or Inconsistent Joist Spacings:  Will increase the labour time and difficulty of installation, raising costs.

Accessibility and Preparation

Distance Between Ground and Floorboards – The commercial minimum height for effective insulation installation is typically 400mm, though some companies prefer 500mm. Many will not work below 400mm due to the difficulty in maneuvering and installing the insulation, as well as the safety risks associated with working in a tight pace. 

Access Point Size –  A small or difficult-to-access opening to the underfloor area can slow down the installation process, making it more labor-intensive and costly.

Pre-Installation Work – Addressing issues such as moisture, mould, or structural damage is crucial before installing insulation. The presence of toxic chemicals or asbestos must be checked and remedied, adding to the preparation costs.

Asbestos – A special mention.  If asbestos is present, having it professionally removed is critical.  To be clear on the risk, if asbestos had been present in a home at quotation time, ecoMaster would not proceed to installation even if the asbestos had been removed. 

Labour Costs and Location

Professional Installation – Hiring experienced professionals ensures proper installation but increases labour costs. Labour rates vary by region, with urban areas typically charging less than rural locations.  Regional and rural locations will have a time and distance calculation added.  Occasionally an overnight allowance will need to be included.  

Installation Method –  Different methods, such as using a supporting membrane versus direct stapling, can affect labour intensity and cost. Methods that require more meticulous work and additional materials will be more expensive, but they will also last as long as your insulation warranty.  Please avoid any quote that uses “friction fit”!

Seasonal Considerations

Spring and Summer will be the time to secure your underfloor insulation installation at the lowest possible cost.  Autumn and Winter are peak seasons, where it is difficult to secure the quality installer, simply because of demand. 

Parking and Site Accessibility

Ensuring that the installation crew has convenient parking on site can save time and reduce costs. If they have to use timed street parking, it can slow down the process and potentially increase labour costs.  Any council that charges 

And One Other Thing …

After 20 years of installing underfloor insulation, one aspect of an installation that was generally one of the first things that the installers would say when they returned to base was whether they were offered morning tea and if accessing a toilet was a challenge.  


Be a delightful human, show your installation crew where the toilet is, offer them morning tea and look after them well.