Before you buy land or get too deep into the planning process, be sure to get a soil test done! Soil (geotechnical) tests determine foundational requirements (literally!) and highlight risks upfront to save you from encountering expensive surprises mid-build.
This is especially important in Coffs Harbour, which has variable soils, high rainfall and moisture-driven ground behaviour.
Take this simple example. A soil test on your proposed site reveals a bearing capacity of 50kPa (kiloPascals). But you want to build a pool on your property to keep the kids cool and content throughout the long summer months (or most of the year in Coffs!) The thing is, the pool requires a kPa of 100… All of a sudden, you’re drilling deep concrete columns (board piers) into the ground until they reach a soil or rock layer strong enough to support the required weight. So now there’s $30-40,000 of extra costs on the job just to lay a stable slab or build your pool.
The beauty of getting a soil test done before you buy is that while it seems like an extra cost, it’s also a valuable bargaining chip with which to negotiate a better purchasing price.
Various ways that soil tests impact your build
- Determines the foundation requirements for your specific block
Soil can differ significantly even between nearby properties. A soil test helps define safe bearing capacity and whether you’ll need engineered footings, slab design adjustments, or piers.
- Reduces the risk of ground movement and cracking
Soils in coastal and sub-coastal areas can shrink or swell with moisture changes. Knowing your soil behaviour helps designers reduce the risk of cracks, uneven settlement and door/window misalignment.
- Guides drainage and moisture management
In wetter conditions, poor drainage can lead to ongoing moisture problems around the home. Soil test findings help inform subsurface drainage, stormwater management and how to keep moisture levels stable around foundations.
- Supports compliance with engineering and certification
Geotechnical data is often required (or strongly recommended) so the design team can produce foundations that meet engineering standards and local compliance expectations.
- Avoids expensive mid-project changes
Without a soil report, you might only discover site constraints once construction is underway—leading to foundation redesigns, delays, rework and added costs.
- Improves renovation and extension outcomes
For extensions/renovations, soil testing helps prevent the “what if” problems—like whether the existing footings are adequate or whether the new work needs different designs to match ground conditions.
When to get it done
Best done before purchasing a piece of land – and definitely before designs are finalised and before excavation begins.
Questions to ask your builder
- Can you arrange a geotechnical soil test before we finalise the design?
- Will the report be used to confirm foundation type and footing depth?
- How will it affect drainage and damp/moisture control?
- Do we need an engineer’s recommendation based on the results?
Pacbuild’s tailor-made approach means that we come alongside you, no matter what stage you’re at. Whether you need the full package (soil test and all!) or already have some of the puzzle pieces and now need help pulling them together. Get in touch so we can help your plans and dreams take root in good soil!