Foundations for Expandable Homes in Queensland
An expandable home needs a stable, level base. Get this right and the home unfolds cleanly, its doors and panels line up, and water stays away from the frame. This guide covers the base options, our recommended footing layout, and where your engineer and certifier make the final call.
Base options
Depending on your site and how you'll use the home, it can sit on any of these:
| Base | What it is | Notes |
|---|---|---|
| Concrete footings | Individual concrete pads under the frame's support points | Our recommended starting layout (see below) |
| Steel piers | Adjustable steel posts on footings | Useful where the ground is not perfectly flat |
| Concrete slab | One continuous concrete base | Must be poured and cured before delivery |
| Levelled gravel pad | A compacted, level gravel surface | Confirm suitability with your certifier for permanent use |
Recommended footing layout
For footing-based installations, this is our starting recommendation:
| Item | Recommendation |
|---|---|
| Number of footings | 6 to 12, depending on model |
| Type | Concrete blocks or steel piers |
| Recommended size | 400mm × 400mm |
| Minimum depth | 300mm, varies by soil type |
The exact number and position of footings depends on the model. Longer homes need more support points. We can provide the layout for your chosen model before you start site works.
How the home is levelled
On delivery day, the installer will:
- Position the home on the footings
- Check it is level
- Make sure the weight is evenly distributed
Levelling matters more for an expandable home than for a fixed one. The fold-out walls and floor sections need to meet the main module accurately. Peg out the exact home position before delivery so footings line up with where the home will sit.
Drainage around the base
Water should never pool under the home. Slope the ground slightly away from it, and add gravel or drainage channels where needed. A dry underside helps prevent rust, mould, footing movement and moisture damage.
Who decides the final design
Our footing layout is a starting point, not an engineered design. Your engineer or building certifier has the final say, and their requirements can change based on:
- Soil type and how reactive it is
- Your site's wind region
- Whether the home will be a permanent dwelling
- Slope of the block
- Local council and certifier requirements
Footings are normally inspected as part of building approval. The council approval guide and the Class 1a guide explain where that fits. For access, levelling and the full pre-delivery checklist, see the site preparation guide.