Resin Injection in Sydney

What resin injection in Sydney actually involves

A 2010 paper by Buzzi, Fityus and Sloan, whose abstract we read, says the resin is injected incrementally under a structure to reach a desired foundation level, forming a composite resin and clay material. The abstract says the resin cannot prevent the soil from rehydrating, but that the long-term risk of overlifting is limited. We did not read the paper's full text and take no figure from it.

What the University of Newcastle says

The University's research page says the resin can fill the desiccation cracks formed as soil shrinks, so a later wetting of the soil could increase swelling and overlift the remediated foundation. It adds that laboratory swelling tests on large injected and non-injected specimens did not show that the injected ones swell more. So the useful question for a provider is why resin suits this ground and this depth.

A 2021 open-access review of the technique lists limits: a relatively high material cost, susceptibility to UV light and microbial degradation, and reach of up to 10 m in the soil, confining it to shallow foundations. It also says the published documentation is rare compared with other techniques. In NSW, underpinning or piering work valued above A$5,000 needs a contractor licence; ask which category a resin job is done under.

Resin Injection in Sydney — common questions

Is resin injection cheaper than other underpinning?

We found no independent source that compares them. Published prices come from firms selling one method or the other; the costs page shows the resin band three firms publish.

Can resin lift a slab too far?

The University of Newcastle says overlifting is a concern where resin fills shrinkage cracks and the soil later wets, but its large-scale laboratory tests did not show injected specimens swelling more.

Does resin injection suit deep footings?

A published review says it reaches up to 10 m in soil depth, which confines it to shallow foundations.