Wall Wrap vs Cavity Insulation: What’s the Difference?
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When building or insulating a home in Perth, you’ll often need both wall wrap and cavity wall insulation. But what exactly do these layers do—and how are they different?
Let’s break it down so you can make the right decision for your project.
What Is Wall Wrap?
Wall wrap is a pliable membrane applied to the outside of a building’s frame, typically before the external cladding is installed. It acts as a protective barrier against wind, dust, and water ingress, while allowing moisture to escape from the inside.
Wall wraps also provide a secondary radiant barrier—reflecting heat away from the structure when combined with an air gap.
Common Uses:
- Protects timber or steel frames during and after construction
- Improves air-tightness and reduces draughts
- Offers temporary weatherproofing during the build
What Is Cavity Wall Insulation?
Cavity wall insulation refers to bulk insulation batts installed between the studs of internal or external wall frames. Its purpose is thermal resistance—it slows the flow of heat in and out of your home, helping keep temperatures comfortable year-round.
Unlike wall wraps, cavity insulation is your primary thermal barrier.
Popular Options:
- Trade Select ThermalCavity – Lightweight, flexible, and easy to install behind wall lining
- Earthwool R2.7 HD Batts – High-performance wall insulation with acoustic benefits
Wall Wrap vs Cavity Insulation: Key Differences
| Feature | Wall Wrap | Cavity Insulation |
|---|---|---|
| Primary Function | Weather and radiant barrier | Thermal resistance and soundproofing |
| Location | Outside the frame, under cladding | Inside the wall cavity between studs |
| Installation Time | Before cladding | Before plasterboard/gyprock |
| R-Value Contribution | Low | High (R2.0–R2.7+) |
Do You Need Both?
Yes—for most Perth homes, you should use both wall wrap and cavity insulation. They serve different roles and work together to create a complete building envelope that protects against heat, moisture, and air leaks.
This is especially important when building with metal framing, where thermal breaks may also be required.
What About R-Values?
Wall wrap contributes minimal R-value unless paired with reflective air gaps. For true energy savings, focus on cavity insulation such as:
- Earthwool R2.7 HD for external walls
- R-Value Chart →
Need Help Choosing?
Not sure which wall insulation is right for your project? Whether you're building new, renovating, or lining a shed, our team can help you get it right—with same-day pickup available in Canning Vale or Osborne Park.
Call 0417 910 326 or shop online now to get started.