If you’re comparing resin injection vs concrete underpinning to fix a shifting foundation, you need clear facts fast. We explain the difference and show which method suits Sydney soils and your budget.

We are Underpinning Sydney, structural preservation specialists with over 20 years’ experience. We are fully licensed, insured and use council‑compliant methods that meet AS2870. Our team gives honest assessments and avoids upselling.

Typical concrete works require excavation and can take days to weeks, while engineered expanding polymers often finish in one to two days with minimal mess. Costs and disruption vary by ground conditions, so we coordinate reports and fixed‑price quotes to keep things simple.

Start with a free, no‑obligation structural assessment. Call 1300 970 930 and speak to Chris, or email photos for a preliminary view before booking a site inspection.

Key Takeaways

We compare the two main methods so you can choose a safe, compliant fix.
Our team has 20+ years’ experience with Sydney soils and structures.
One option can be quick with minimal mess; the other is more disruptive but traditional.
We provide free assessments, fixed‑price quotes and engineering coordination.
Safety and AS2870 compliance protect your home and resale value.

Foundation warning signs in Sydney and why prompt, compliant underpinning matters

Early warning signs in walls and floors are a homeowner’s best chance to act. Look for cracks walls near windows and doors, floors that slope and doors or windows that stick. These signs often signal subsidence or movement in the existing foundation.

In Sydney, reactive clay and changing soil moisture drive much of the movement. Tree roots, poor drainage and leaking services let water travel and undermine the ground under footings. Left unchecked, small cracks become structural damage and can affect other buildings nearby.

Acting early reduces scope and cost. We assess soil, drainage and structural issues so the solution treats the cause, not just the symptoms. Compliant works follow AS2870 to avoid differential movement on clay sites.

Look for cracks, sticking frames and uneven floors.
Fix drainage and moisture sources before works begin.
We offer a free, no‑obligation assessment and honest advice.

Call 1300 970 930 to speak to Chris or email photos for a preliminary view. We explain options simply and provide transparent, fixed‑price quotes for safe, compliant underpinning.

Resin injection vs concrete underpinning: method, time, cost and compliance compared

We set out how small‑hole, high‑precision lifting compares to excavated mass concrete so you know what to expect on site.

How each method works

Small‑hole injection underpinning drills discreet holes and injects an expanding polymer that compacts soil and fills voids. Technicians use laser levelling to control staged lifts and protect finishes.

Excavated mass concrete involves staged digs beneath the existing footing, forming and pouring concrete beams or pads. It requires cure time before load transfer.

Time, disruption and soil suitability

Small‑hole projects commonly finish in one to two days with minimal noise. You often remain in your home during works.

Excavated works can run days to weeks. They create spoil, noise and access limits. On reactive clay soils, staged partial pours may risk differential movement under AS2870 if not designed correctly.

Cost, footprint and precision

Guideline costs: mass concrete from about $1,000–$3,000 per metre; beam and base higher; many small‑hole projects fall between $4,000–$15,000 depending on scope and access.

Environmental and reinstatement costs tend to be lower with small holes. Excavation produces spoil, dust and reinstatement labour.

Feature	Small‑hole method	Excavated method
Typical duration	1–2 days	Days to weeks
Site spoil	Minimal	High (trenches, waste)
Precision control	Laser levelling, staged lifts	Depends on staged pours and engineers’ checks

We match the method to site testing and AS2870 compliance.
We provide fixed‑price quotes, engineering reports and documented outcomes.

When to choose resin, when to choose concrete underpinning, and where screw piling fits

The best solution for a moving foundation depends on ground conditions, the area affected and your occupancy needs.

Resin injection underpinning is clean and fast. We recommend it where reactive clay soils and moisture swings cause movement. It suits tight access and internal areas. You can often remain in your home during works.

When mass concrete is right

Concrete underpinning is practical for small, heavy sections or where a local mass unit is the correct load solution. It is slower and more disruptive. On reactive clay, staged partial pours must be engineered to meet AS2870 to avoid differential movement.

Screw piling and deeper options

Screw piles extend support to deeper competent layers when near‑surface soils are weak or variable. They bypass poor ground beneath shallow footings and suit sites needing greater depth or capacity.

Choose injection underpinning for reactive clays and minimal disruption.
Pick concrete underpinning for specific small areas or heavy loads.
Use screw piling where deeper strata are required or soils vary.
Combine moisture control and drainage on clay sites to reduce future movement.

Issue	Best method	Key benefit
Reactive clay, internal access	Resin injection underpinning	Fast, low reinstatement, controlled lift
Small heavy area or local footings	Concrete underpinning	Mass capacity, proven traditional method
Very weak or variable soils	Screw piling	Transfers load to deeper competent strata

We recommend the right method without upselling. Our engineers match soil testing, structure and access, then document the design for compliance. For a free assessment, call 1300 970 930 or book a review at Underpinning Sydney.

Our engineering-led process: honest assessment, compliant methods and documentation

We lead every job with a clear engineering process so you know what will happen on site and when. Our goal is to protect your foundation, limit disruption and leave a full record for council and resale purposes.

Free structural assessment and photo review

Start with a no‑obligation assessment. Email photos for a quick preliminary view or book a site visit. We review your photos, note visible cracks and outline likely works before any quote.

On‑site testing and laser monitoring

On site, underpinning involves testing soil and monitoring movement. We use laser levelling to set safe lift limits and protect nearby buildings and walls.

Transparent quotes, council compliance and certification

We provide fixed‑price quotes that detail scope, labour, programme and reinstatement. Methods are council‑compliant and backed by engineering reports and certificates.

Minimising disruption and coordinating repairs

Many projects let homeowners stay in their home. Where more access is needed we manage spoil, safety and noise. We also coordinate crack repairs, subfloor ventilation and retaining wall support.

Stage	What we do	Benefit
Assessment	Photo review + site testing	Faster, tailored quote
Monitoring	Laser data + engineer checks	Controlled lift, less risk
Completion	Reports + certification	Council‑ready documentation

Call 1300 970 930 and speak to Chris to arrange your free assessment and lock in a site visit.

Conclusion

A clear, engineered fix brings foundations back to safe, long‑term performance.

Fast, laser‑controlled resin injection underpinning often gives a clean stabilisation in one to two days. Traditional concrete underpinning still has a place for specific local needs but is slower and more disruptive. Both must match soil behaviour to avoid new cracks or subsidence.

We are licensed, insured and council‑compliant. We give honest assessments, fixed pricing and full certification. Email photos for a quick preliminary view or book a site inspection.

Call 1300 970 930 and speak to Chris to secure your foundation and protect your property value.

FAQ

What are the common warning signs my Sydney home needs foundation work?

Cracks in walls or ceilings, doors and windows that stick, sloping floors and new gaps at skirting are common signs. In Sydney, seasonal clay shrink‑swell and poor drainage often cause these symptoms. We recommend a prompt assessment to confirm cause and risk.

How do expanding polymer methods compare with mass concrete methods for foundation repair?

Expanding polymer is installed through small holes beneath footings to lift and stabilise selectively. Mass concrete requires trenches or pits beneath foundations to pour new support sections. Polymer is quicker with less digging; mass concrete suits heavy loads or where access and design dictate larger new supports.

How long does each method typically take on site and how disruptive are they?

Small polymer jobs are often completed in a day or two with minimal noise and little landscaping impact. Mass concrete projects can take weeks due to excavation, formwork and curing times, and they generate more dust and access needs. We plan works to keep disruption to a minimum.

Which soil types in Sydney are suitable for each repair method?

Reactive clay soils with seasonal moisture change often respond well to polymer stabilisation because it limits excavation. Mass concrete or screw piles suit sites where deeper, stable strata are required. We follow AS2870 guidance and test on site before recommending a solution.

What are the cost differences and typical price drivers?

Costs depend on access, excavation, labour, required depth and remediation extent. Polymer options usually cost less for small, localised lifts. Mass concrete and piling are costlier due to labour and materials. We provide fixed‑price quotes after inspection and testing.

How do environmental impact and clean‑up compare between the methods?

Polymer methods leave small access holes and produce minimal spoil. Mass concrete needs trenches and more waste handling, plus water and dust control measures. Both approaches are managed to meet local environmental and council requirements.

How precise are the lift and levelling controls with each technique?

Polymer systems allow staged, measured lifts using laser levelling and monitoring for fine control. Mass concrete offers structural robustness but less incremental adjustment once poured. We use laser monitoring on every job to protect structural integrity.

When is mass concrete the preferred choice over polymer stabilisation?

Mass concrete is preferred for large structural footings, severely degraded sections, or where design requires adding bulk new support. It is also chosen when deeper excavation for services or drainage coincides with foundation works.

Where do screw piles fit into foundation repair in Sydney?

Screw piles transfer loads to deeper, competent layers. They are ideal when near‑surface soils are weak or variable and when minimal vibration and fast installation are needed. Engineers specify pile depth and spacing based on site tests.

Do you provide engineering reports and council‑compliant documentation?

Yes. We supply fixed‑price quotes, engineered designs, monitoring records and compliant certification. All work follows local council requirements and Australian standards to ensure long‑term compliance and resale confidence.

Can we stay in our home during the works?

In many cases yes. Polymer methods often allow occupants to remain. Larger mass concrete or piling projects may need temporary access restrictions. We plan to minimise disruption and coordinate ancillary repairs like crack remediation and ventilation where needed.

Do you offer a no‑obligation assessment and what does it include?

We offer a free preliminary photo review and a no‑obligation on‑site structural assessment. This includes visual inspection, basic tests and guidance on likely solutions. Detailed quotes follow site testing and engineering checks.

How long do repairs last and what warranty do you provide?

When designed and installed to engineering standards, repairs provide long‑term stability. We provide workmanship warranties and supply manufacturer or design warranties where applicable. Detailed terms are included in our proposal.

How quickly should I act if I suspect subsidence or foundation movement?

Act promptly. Early assessment prevents further damage and reduces repair costs. We advise contacting a qualified team for inspection as soon as you notice warning signs to secure safety and property value.