Independent quantum evidence in a roofing and cladding adjudication

We supported a main contractor with independent quantum expert evidence in a roofing and cladding adjudication on an education project. Instructed at Reply stage, we issued our first report two days later, testing disputed completion and remedial costs against the contract, project records and opposing expert evidence.

Background

The main contractor had engaged others to complete and rectify work and had purchased additional materials. The subcontractor challenged both its responsibility for those costs and the amounts claimed. By the close of submissions, the two expert assessments differed substantially, producing account calculations that pointed to payment in opposite directions.

We were instructed after the Referral, Response and opposing expert’s first report had already been served. Joining at Reply stage meant understanding an existing claim and competing expert opinion, tracing the costs through the supporting records, and forming an independent assessment within the time remaining for the Reply. The valuation also needed to distinguish the scope and value of the work from the separate questions of contractual responsibility.

Our approach

Within that two-day period, we structured the assessment around ten heads of cost, retaining a consistent comparison between the claim, the opposing expert’s assessment and our own opinion. Each item was tested against the underlying documents and set out in the expert report for the Reply.

For the replacement contractor’s work, we compared the original contract sum build-up with the replacement order for equivalent scope. This established what the price included and addressed an assessment that treated the replacement package as principally labour. We then tested the further pricing information against the subcontract documents and payment evidence.

For materials, we reconciled invoices and transaction information and distinguished between different products within the supplier records. We checked the basis of percentage deductions and considered what the documents established about purchase, delivery and incorporation. This made the quantities, values and remaining evidential gaps clear for each disputed item.

The roof labour assessment required a separate reconstruction. We reviewed allocation and daywork records by operative and period, reconciled them with the applications, and compared the charged rates with those used in the subcontractor’s own variation account. That exercise reduced the client’s roof cost claim. It also provided a basis grounded in the project records for assessing labour costs alongside the published benchmark rates used by the other expert.

For scaffolding and powered access, we distinguished cumulative certified work from a net payment for a particular period and checked the invoices against the remedial chronology. We assessed the cost evidence while identifying the assumptions about why the costs had arisen.

Our supplementary report for the Surrejoinder was dated four days after the opposing party’s Rejoinder. It addressed the new expert calculations item by item and incorporated further payment and allocation evidence. Our overall assessment remained below the client’s original claim, reflecting the adjustments identified through the review.

Outcome

The adjudicator accepted our roof remediation valuation in full, agreeing that “the use of Contract rates, where available is preferable”. The replacement insulation cost was also accepted, and the tile supply valuation largely followed our assessment.

The adjudicator’s overall assessment of the remediation costs was closer to our valuation than to the alternative expert assessment.