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Construction Dispute Specialists

Quantum and quantity surveying expert services

GTQ Expert Services provide quantum and quantity surveying services for engineering and construction projects in the oil and gas, civil engineering, building, transport and heavy industry sectors.

Our team provide a range of services including dispute avoidance & preparation and appointments as the quantum expert witness to some of the most high profile projects across the globe.

GTQ Expert Services is regularly appointed to disputes determined in international arbitration, supreme court litigation, domestic arbitration, adjudication and other similar forms of dispute resolution.


+61 (0) 457 515 046





Based in Brisbane, Australia, GTQ Expert Services holds a depth and wealth of local and international experience on disputed projects in Australia, New Zealand, PNG, Malaysia, Indonesia, Hong Kong, Singapore, South Korea, United Arab Emirates and Africa.

Extensive experience across multiple sectors including oil and gas, civil engineering, building, transport and heavy industry sectors. GTQ Expert Services draws on actual site and project experience in both the engineering and construction fields to disentangle complex issues and provide practical advice and evidence.

Our team has produced reports and submissions for many of the worlds leading contracting organisations and lawyers, including law firms in the Magic Circle.

Leading Expert - Graham Topp

Graham is a Fellow of the Royal Institution of Chartered Surveyors, and a registered expert witness, certified quantity surveyor and Fellow of the Australian Institute of Quantity Surveyors.

Graham is involved in the preparation, analysis, and submission of expert witness reports, addressing issues of quantum. He is retained to prepare reports on construction and engineering disputes in domestic and international arbitration, litigation, adjudication, and expert determination.

Graham has provided estimating, procurement, contract, claims (typically related to the valuation of delay and disruption, loss and expense and final accounts) and commercial management on a broad range of projects including rail, metro, power, steelmaking, oil and gas, airport, bridge, commercial, residential, civil, educational, health and industrial. He has worked with standard and bespoke main contracts and subcontracts.

WWL says:

Graham has a strong reputation with peers and clients alike, who say he draws high praise for "skillfully explaining complex quantity-surveying data and issues simply and practically".

"Graham is a respected figure in the Australian and New Zealand markets, commended for his outstanding work dealing with disputes of quantum."

His “robust advice” and “excellent presentation as an expert witness” receive further praise. Graham impresses market sources who remark he is “highly professional, incredibly personable and adaptable in contentious matters”.

Graham is widely celebrated by peers and clients for his “excellent technical and analytical skills”.

Brisbane, Australia

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