Service · Design change comparisons

Design change
comparisons.

The hydraulic design has changed mid-project. You need to know exactly what changed, exactly what it costs and exactly how to document it. SNZ compares your two drawing sets and delivers a clear, priced breakdown — fast.

2 Drawing sets compared
Clear Cost breakdown
Fast Turnaround
Any Project type
Request a comparison
What a comparison delivers
Original drawings
Hot water riser — 100mm
Cold water — 80mm
Sanitary stack — 100mm
Greywater system
Revised drawings
Hot water riser — 100mm
Cold water — 80mm
Sanitary stack — 150mm
Rainwater harvesting
Net cost difference — clearly priced Stack upsize + new rainwater system − greywater omission = net variation cost

Design changes happen.
The cost must be captured.

On any complex construction project, the hydraulic design will change. Sometimes once, sometimes many times. Every change has a cost — and every cost that is not captured, documented and claimed is money left behind.

A design change comparison is different from a variation assessment. A variation prices the additional scope from a single instruction. A design change comparison takes two complete drawing sets — the original and the revised — and produces a comprehensive, side-by-side analysis of everything that changed across the entire hydraulic scope.

The result is a document you can use for contract administration, variation claims, EOT submissions or commercial negotiations — a clear, priced record of exactly what the design change cost.

Full drawing set comparison
Both drawing sets completely measured and priced — not a selective review of what looks different. Every system, every level, every change identified.
Net cost clearly identified
Additions, deductions and net cost difference clearly separated and presented — so the commercial impact of the design change is unambiguous.
Defensible documentation
Produced by an independent specialist estimator — not the subcontractor pricing their own variation. That independence makes the comparison credible to the principal.
Fast turnaround
Design change comparisons are time-sensitive — contract administration windows don't wait. SNZ prioritises these for fast delivery.

Four steps.
One clear answer.

01
Send both drawing sets
Original hydraulic drawings and revised hydraulic drawings — plus the specification and any relevant RFIs or instructions.
02
We measure both sets
Full PlanSwift takeoff of both drawing sets — every system individually measured so the comparison is based on actual quantities, not estimates.
03
Differences identified
Every change identified and categorised — additions, deductions, material changes, system changes. Nothing missed.
04
Net cost delivered
Clear, itemised cost comparison delivered — additions, deductions and net cost difference. Ready for contract administration or variation claim.

Design has changed
on your project?

Send us both drawing sets and we will come back within a few hours with a turnaround time and fee. Fast, clear and defensible — every time.