Peter is a licensed builder with over 45 years of experience in the construction industry. In 2012, his expertise in energy efficient construction inspired the invention of ThermaDoor Premium garage door insulation - the original purpose made garage door insulation in Australia.
Insulation is often treated as interchangeable.
If a product works in a wall, floor or ceiling, it’s often assumed it will work just as well on a garage door.
That assumption is where most garage door insulation problems begin.
In reality, wall insulation is not garage door insulation.
Garage doors are moving, weight-sensitive mechanical systems, and insulation designed for static building elements does not translate to safe or effective performance on a door.
No. Wall insulation is not designed for garage doors.
Wall insulation is engineered for static cavities where weight, balance, and movement are irrelevant.
Garage doors must account for:
Added weight
Weight distribution
Door balance and spring tension
Ongoing movement and flex
Ignoring these factors can compromise both performance and safety.
Most garage door insulation products available today are wall insulation products repurposed for garage doors.
These materials were originally designed for:
Walls
Floors
Ceilings
Acoustic panels
Static building assemblies
They are then adapted, often without full consideration of weight or long-term behaviour, and marketed as garage door insulation.
A garage door:
Opens and closes multiple times a day
Moves through tracks and hinges
Relies on precisely balanced springs
Is engineered to strict weight tolerances
A wall:
Does not move
Does not carry mechanical load
Does not require balance
Wall insulation assumes weight is irrelevant.
On a garage door, weight is critical.
Garage doors are designed to operate within a narrow weight range.
Adding insulation without accounting for:
Total installed weight
Even weight distribution
The door’s spring capacity
can lead to:
Unsafe door operation
Increased strain on motors and springs
Accelerated wear and failure
Voided door warranties
This is where many repurposed wall insulation products fall short.
Some commonly repurposed insulation types present specific risks on garage doors.
PIR is typically designed for walls and the underside of carparks – not moving doors.
On garage doors:
PIR is heavy for its thickness
Added mass increases load on springs and motors
Weight is often quoted per square metre without context of door dynamics
Even small increases in weight can materially affect door balance over time.
Open-cell products such as batts and acoustic wall panelling are other materials frequently repurposed for garage doors.
These products:
Are designed for sound absorption, not thermal systems
Absorb moisture from condensation and humidity
Increase in weight when wet
Can remain damp against a metal door skin
As moisture is absorbed, the insulation becomes heavier, placing additional and unpredictable load on the door.
This weight increase is rarely disclosed or considered at installation.
Garage doors experience:
Night-time cooling
Morning condensation
Seasonal humidity changes
When insulation absorbs moisture:
Its thermal performance drops
Its weight increases
Load on the door system changes over time
This creates a compounding problem:
the door gets heavier after installation, not lighter.
Wall insulation is not designed to manage this risk on a moving, external surface.
For garage doors, it’s not enough to know:
The material weight on paper
What matters is:
The correct installed weight
The weight after moisture exposure
The weight distributed across the door
Whether spring balance is adjusted accordingly
Insulation that looks “light enough” in isolation can still create problems once installed on a real door in real conditions.
Installation method affects:
Moisture exposure
Weight distribution
The AS/NZS 4859.2:2018 standard recognises that insulation performance depends on the entire installed assembly, not just the material.
While the standard focuses on thermal performance, the same principle applies mechanically:
real-world performance depends on the system, not the product alone.
When you combine:
Movement
Metal construction
Thermal bridging
Installation method
Weight and moisture behaviour
it becomes clear why garage door insulation cannot be borrowed from wall or acoustic systems.
Garage doors require insulation that is:
Purpose-designed
Weight-controlled
Moisture-resistant
Tested and validated for the application
Wall insulation is not garage door insulation.
Garage doors are weight-sensitive mechanical systems.
Materials designed for walls, floors, or acoustics often ignore this reality.
Insulation that:
Is heavy
Absorbs moisture
Gains weight over time
can compromise door safety, performance, and longevity.
Understanding weight — not just R-value — is essential when insulating a garage door.
Choosing garage door insulation isn’t just about R-value.
Weight, moisture behaviour, installation method, and door balance all matter — especially on a moving door.
To help homeowners compare options properly, we’ve created a Garage Door Insulation Buyer’s Checklist.
It covers:
Installed weight (not just material weight)
Moisture absorption and long-term load
Installation method and air gaps
Door balance and spring considerations
Key questions to ask before committing
Download the Buyer’s Checklist (PDF) to make sure the insulation you choose is suitable for a garage door — not just a wall.
Free. Practical. Written for Australian homes
No. Wall insulation is not designed for garage doors. Walls are static structures, while garage doors are moving, weight-sensitive mechanical systems. Insulation designed for walls does not account for door movement, balance, metal heat transfer, or ongoing mechanical load.
Garage doors are engineered to operate within a narrow weight range. Adding insulation increases the load on springs, tracks, and motors. If weight is not properly accounted for and balanced, it can lead to unsafe operation, increased wear, and reduced door lifespan.
Yes. Some insulation materials absorb moisture from condensation and humidity. As they absorb moisture, they gain weight. This means a garage door can become heavier after installation, increasing strain on the door system over time.
PIR insulation is typically designed for walls, roofs, and floors — not moving doors. It is relatively heavy for its thickness, and even small increases in weight can affect garage door balance and spring performance if not properly managed.
No. Open-cell acoustic panels are designed for sound absorption, not thermal insulation on external metal doors. They readily absorb moisture, become heavier when wet, and can remain damp against the door skin, increasing both weight and corrosion risk.
Material weight alone does not reflect real-world conditions. What matters is the installed weight, including how the insulation is fixed, how weight is distributed across the door, and how moisture exposure may change that weight over time.
Yes. Any added weight affects door balance. If insulation is installed without adjusting spring tension accordingly, the door may become harder to open, strain the motor, or operate unsafely. Proper consideration of balance is essential.
No. While R-value matters, it is only one part of the picture. Weight, moisture behaviour, thermal bridging, installation method, and door movement all influence real-world performance. Focusing on R-value alone can lead to poor outcomes on garage doors.
Homeowners should look beyond marketing claims and ask about installed weight, moisture absorption, installation method, and whether door balance has been considered. Using a structured buyer’s checklist helps ensure insulation is suitable for a moving garage door, not just a wall.
Call, text, or send an enquiry below to see if we have an installer in your area.
