After working for one and a half years as a legal assistant at the Dordrecht court, William joined Kneppelhout as an attorney in 2010 and became a partner in 2020. At Kneppelhout, he manages a litigation and advisory practice focused on construction law, tenancy law, and real estate law in general. His clients include both professional and private principals, contractors, architects, housing corporations, governments, electrical engineering firms, investors, and property managers. He advises them on (the formation of) construction and tenancy contracts and general terms and conditions such as UAV 1989/2012, UAV-GC 2005, AVA 1992/2013, DNR 2005/2011, and RAW 2005/2010.

His clients describe him as a knowledgeable and committed attorney who quickly gets to the heart of the matter, communicates effectively, and maintains a practical and result-oriented approach. In 2015, William passed the exam for the specialization course IBR Private Construction Law, and in 2014, Memory Magazine included him in the Best Young Professionals Law Top 50. He is a member of the Association of Construction Law Attorneys and an active member of the Rotterdam Real Estate Society ‘De Nieuwe Maas’.

“Since 2000, I have been living in Rotterdam and feel perfectly at home in this enterprising and dynamic city where literally every day is built towards the future. The same Rotterdam mentality prevails at Kneppelhout, and every day I contribute with great dedication and enthusiasm to the future of our clients. My approach is aimed at carefully advising the client in the preliminary phase of a project to minimize risks.​

During the execution phase, I switch quickly because I know that unnecessary delays must be avoided. However, if it best serves the client’s interests, I am the designated person to seek justice in a procedure at the court or the Arbitration Board for the Building Industry. My work experience at the court has proven to be of added value in that regard.”

• Involved as an attorney for an industrial port company in a complex and widely commented arbitration dispute concerning (the consequences of termination of) an integrated contract (UAV-GC 2005).
• Involved as an attorney for a water board in a legal procedure regarding defects in a hydraulic structure (UAV-GC 2005).
• Attorney for a professional client in a legal procedure concerning hidden defects in a building housing a popular tourist attraction in Amsterdam (UAV 2012).
• In-house attorney for multiple architectural firms, advising them on the formation of consultancy agreements and conditions (DNR 2011).
• Attorney for the client of the first fully wooden high-rise complex constructed under subcontracting. Drafted the construction and coordination agreements (UAV 2012).
• In-house attorney for urban restoration organizations, advising them on purchase and lease agreements and representing them in legal proceedings.
• In-house attorney for multiple professional investors, developers, and housing corporations, continuously assisting them with concise and practical advice on (re)developing and managing their real estate, drafting lease and construction agreements, and advising on homeowners’ association (VvE)-related matters.

In his spare time, William plays tennis at LTC Plaswijck’62, plays football at V.O.C. and can also be found on the padel court.