Add space to your home — without the stress of a full renovation
Fixed-size extensions built using high-performance materials. Faster, simpler, and designed to actually improve how your home feels
A simpler way to extend your home
Box on the Back is a streamlined extension option designed for homeowners who want more space without the complexity of a full custom build. By working with fixed sizes and proven construction methods, we reduce design time, minimise unknowns, and create a cleaner, more predictable outcome.
Small
3.6m x 3.0m
Ideal for a home office, guest room or compact extra living space.
From $32 400
Medium
4.8m x 3.6m
A flexible option for a bedroom, sitting room or larger multi-use space.
From $47 520
Large
7.2m x 4.8m
Ideal for open-plan living, a master suite or a more substantial extension.
From $86 400
Transportable & Built for Your Site
Our extension modules are designed to be delivered and constructed across Victoria, making them a flexible solution for a wide range of locations.
Each project is assessed individually to ensure the best outcome for your site, access, and orientation.
Pricing & Inclusions
Pricing shown is indicative and based on our standard extension designs.
Final pricing may vary depending on:
- Site conditions
- Access to the build area
- Foundation requirements
- Final scope and selections
Drafting, engineering, permits and site-specific approvals are not included in the base price and will be confirmed as part of your project proposal.
What’s included
- Structural Insulated Panel (SIPS) construction
- Double glazed UPVC windows
- Colorbond roofing
- James Hardie external cladding
- Electrical fit-off
- Plastering and painting
- Fully finished internal space
Built better than a typical extension
Most extensions are built using standard methods, which can lead to rooms that are too hot, too cold or disconnected from the rest of the home. We use high-performance materials and building principles so your new space actually improves comfort.
- Better insulation and thermal performance
- Reduced drafts and improved comfort
- Built to modern standards, not outdated ones
Is this right for your home?
The best way to find out is a quick site visit. We’ll assess your property, talk through your goals, and give you clear advice on what will work.