When you collect underpinning quotes for a Wagga Wagga home, a 30-50 per cent spread between the cheapest and most expensive tender is completely normal for the same house and the same problem. A careful underpinning quote comparison needs to look past the total number and ask what each quote actually includes before you can decide which represents genuine value. Our underpinning service team gets this question regularly, so here is a plain-English breakdown of why the numbers diverge and how to compare them on equal footing.
Method choice is the biggest variable
The single largest reason quotes diverge is that contractors have priced different methods. Mass concrete underpinning, screw piles (helical piers) and resin injection all solve the same underlying problem, a footing that has moved, but they differ enormously in equipment, labour time and materials cost.
Concrete underpinning involves excavating beside each footing in a specific sequence, pouring a new mass-concrete pin, waiting for it to cure, and repeating around the building. It is slower and creates more spoil to remove, but is often cheaper per pin in a straightforward single-storey job on a site with reasonable access. Read more about the process in our concrete underpinning method explained guide.
Screw piles are installed hydraulically with minimal excavation and can be faster on the right site, but the equipment and specialist labour costs start higher. Our screw pile vs concrete underpinning comparison goes through that in detail.
If Quote A is for 14 concrete pins at $X each, and Quote B is for 8 screw piles at $Y each, you are not comparing the same job at all. Before you assume Quote B is overpriced, confirm that the method and the pin count are genuinely equivalent.
Number of pins: educated estimate vs guess
Pin count is the other major variable. A well-prepared quote comes from a physical site visit, a structural assessment, and sometimes a geotech report. The contractor has walked the perimeter, measured settled sections with a level, assessed the load distribution, and estimated how many pins are needed to carry the structure safely to stable ground. Our foundation inspections process feeds directly into that kind of estimate.
A poorly prepared quote comes from a phone description of symptoms, a look at a few emailed photos, and a rough guess. The pin count is lower, the price looks attractive, and variations come later once the crew is on site and realises the scope is larger than assumed.
Watch for the phrase “provisional sum” or “to be confirmed on site”. This is not inherently dishonest, some variation is unavoidable, but a quote with a low provisional pin count and a fixed total price is likely to blow out once excavation reveals a more extensive problem. Our how underpinning quotes are built guide explains what each line item on a proper quote should mean.
Engineering scope: full report or nothing?
Structural engineering is not optional on most underpinning jobs. A qualified engineer has to specify the number, depth and spacing of pins, design the load transfer, and sign off on the completed work. The question is who pays for it and whether it appears as a line item in the quote.
Some contractors include engineering as an explicit cost. Others absorb it into their margin, which is perfectly legitimate as long as the engineering genuinely happens and documentation is provided at the end. Others, particularly on underpriced tenders, skip independent engineering altogether or rely on an in-house assessment that produces no stamped drawings.
A quote with no mention of engineering should prompt questions. Ask: “Who is doing the structural engineering? Is it included in this price? Will I receive stamped drawings and a completion certificate?” If the answer is vague, that is a gap worth quantifying before you compare totals.
Access, spoil disposal and reinstatement
Three commonly omitted cost items separate comprehensive quotes from cheap ones:
Access: Concrete underpinning requires excavation beside footings. Tight side access, under about 900 mm, on an older brick home in central Wagga forces hand-digging rather than machinery, which significantly increases labour time. If the quote does not mention access specifically, ask how the contractor plans to handle it.
Spoil disposal: Excavating even six concrete pits generates a substantial volume of clay and displaced soil. Legitimate contractors include a skip bin or tipper run in the price. Some strip it out to keep the number attractive, leaving the disposal cost for a variation.
Reinstatement: After underpinning, pits need to be backfilled and compacted, paths or garden beds restored, and interior linings patched where cracking has occurred. Some quotes include all of this; some price only the structural work and stop there. Ask directly whether the price covers the site “back to original condition” or only the footing work.
The table below shows a checklist to run through each quote you receive:
| Line item | Should it be in the quote? | Often missing in cheap quotes |
|---|---|---|
| Site visit and inspection before quoting | Yes | Sometimes |
| Engineering design and sign-off | Yes | Often |
| Pin count, depth and method specified | Yes | Vague or provisional |
| Access method and equipment | Yes | Assumed, not stated |
| Spoil removal and disposal | Yes | Stripped out |
| Concrete mix specification | Yes | Generic reference only |
| Site reinstatement | Yes | Excluded |
| Completion documentation | Yes | Often missing |
The cheap-quote trap: what usually gets cut
A quote that undercuts the field by more than 30 per cent is almost always cutting something. The most common omissions in underpriced tenders:
Fewer pins than the job needs. The only reliable way to check whether the pin count is right is an independent engineer’s assessment. Without one, you are relying entirely on the contractor’s self-interest, which may not align with yours.
No engineering documentation. This matters at point of sale. A buyer’s solicitor will ask for the underpinning completion certificate and the engineer’s sign-off. Contractors who do not provide paperwork create a problem for you down the track.
Reinstatement excluded. The crew leaves and your driveway is still in pieces. You find out the reinstatement was always a separate quote.
No clear variation clause. Conversely, some low-ball quotes price light and then charge variations for every scope item not explicitly written into the contract. Read the fine print carefully. The underpinning cost guide explains how total project costs are built, and our how to choose a foundation repair contractor guide covers what contractor credentials to check before signing.
How to normalise three quotes onto one spreadsheet
The practical way to compare is to build a simple spreadsheet with one row per cost item and one column per quote. Fill in whether each item is included, excluded, or unknown. Where items are unknown, phone each contractor and ask directly, a legitimate contractor will answer.
If you are considering a staged foundation repair budget plan, ask each contractor whether they can separate the must-do-now structural scope from the cosmetic reinstatement. That split gives you pricing flexibility.
Then look at the total costs with the gaps filled in. You will commonly find:
- Quote A is cheapest on paper because it excludes engineering and reinstatement. Add $2,000 to $5,000 to normalise it.
- Quote B is mid-range and includes everything.
- Quote C is highest because it uses screw piles rather than concrete: a different method, not necessarily a rip-off.
Once you have adjusted for scope, the mid-range quote usually delivers the best real-world value. The cheapest total rarely ends up cheapest once variations are accounted for.
FAQs
Is a 30-50 per cent price spread between underpinning quotes normal?
Yes, completely normal and common. The spread comes from different methods, different pin count assumptions, different engineering inclusions and different contractor margins. Rather than expecting all quotes to align closely, use the spread as a prompt to understand what each one actually includes. Quotes that can be broken down line by line are far easier to compare than those that offer only a single total price.
Should I always choose the cheapest underpinning quote?
Not automatically. If the cheapest quote includes the same scope, method, pin count, engineering and reinstatement as the others, it may genuinely be the best value. But if it is cheap because key items are missing or the pin count looks optimistic, the final cost after variations can comfortably exceed a higher mid-range quote that covers everything upfront.
What should I do if two contractors quote very different pin counts?
Ask both how they arrived at their numbers. If neither has a structural engineer’s design behind their estimate, commission an independent structural assessment before signing. Our foundation inspections service can provide an independent starting point for the engineering scope.
Do I need my own structural engineer’s report before collecting quotes?
It is not always required, but it levels the playing field. If you have an independent engineer’s report specifying the scope, all contractors are pricing the same brief and comparisons become much more straightforward. Without one, you are comparing each contractor’s self-assessed scope, which will almost always diverge.
What questions should I ask to make quotes comparable?
Ask each contractor to itemise: pin count and method, engineering inclusion, access plan, spoil removal, reinstatement, completion documentation and warranty. If any contractor refuses to itemise or gives evasive answers, that is useful information about how they handle the project overall.