Before We Start: DIY Changes the Cost Equation
When you get underfloor insulation professionally installed, a big part of the cost is labour. And fair enough. Installing insulation under a house is physical work. It can be cramped, dusty, awkward and slow. If access is difficult, joist spacing is inconsistent, or the underfloor area has pipes, wires, bulkheads or other obstacles, the job takes longer.
But if you are installing underfloor insulation yourself, a lot of that “cost” changes shape.
It is still a cost, but it is not necessarily money leaving your bank account. It is your time, your effort and your willingness to shuffle around under the floor doing a job that most people would rather pay someone else to do.
That is why DIY underfloor insulation can be a much more affordable option for many households. You still need to buy the right insulation and the right installation materials, but you are not paying someone else for every hour spent.
So, when you go through the items that make installation more expensive, keep this in mind. If you are doing it yourself, they may still make the job slower, fiddlier or more annoying, but they may not add much to the amount of money you need to spend.
In other words, DIY does not make the hard parts disappear. It just means you are paying for some of them in cups of tea and sore shoulders but you will be getting mega brownie points for making your home toasty warm.
Factors that Make Professional Installation More Expensive
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.
Labour Costs and Location
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.
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.
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.
