Scope gaps between trades can make the lowest quoted figure a poor guide to the final job cost.
A subcontract quote arrives below the budget and the project looks healthier. Then the site team discovers that unloading, access equipment or making good sits outside the price. Another trade assumed the same work was included elsewhere.
The problem is not necessarily an unreasonable quote. It may be that nobody compared the boundaries of the work before accepting it.
Compare the same package
Start with one scope description and ask each tenderer to identify inclusions, exclusions and assumptions against it. Pay particular attention to the points where one trade hands work to another.
Who sets out the work? Who supplies temporary access? Who protects completed surfaces? Who removes packaging, books testing and provides the final records? These questions are specific enough to expose a gap before it becomes a site argument.
Do not fill an omission by assuming the subcontractor will absorb it. Clarify the requirement and obtain the appropriate price or agreement. Changes to scope, timing and payment should be reflected in the actual contract documents.
Price the programme too
Compare when each contractor can perform the work and what must be ready first. A lower price may still be suitable, but the head contractor needs to understand the consequences of an extra mobilisation or a different sequence.
Use a short interface schedule for complex work. List the activity, the trade responsible and the condition required before the next activity begins. Keep it usable on site; a long tender appendix that nobody can find will not prevent confusion.
Payment administration deserves equal clarity. MBIE’s Construction Contracts Act guidance explains the statutory framework for construction payments. Project teams should have their particular terms and payment processes checked rather than treating a purchase order as the whole arrangement.
After completion, compare the accepted package with the final cost. Separate genuine client changes from omissions in the original scope and avoid blaming every extra on “variations”. The lessons belong in the next tender enquiry.
A reliable subcontract comparison makes it clear what is being bought, when it will be delivered and what still belongs to someone else. The best-priced package is easier to identify once those boundaries are visible.