Why Every Instruction on a Construction Site Needs to Be in Writing

A client visits the site on a Tuesday and tells the foreman to move the staircase two metres to the left. The foreman obliges. Three months later, the architect raises a defect notice saying the staircase is in the wrong position. The contractor has no record of the instruction. The argument that follows could have been avoided with one piece of paper.

An Architect's Instruction (AI) or Employer's Agent's Instruction is the formal written directive through which changes to the contracted works are authorised. Under standard construction contracts used in Kenya, including Joint Building Council (JBC) also known as the Green Book by Architect and Quantity Surveyors, and International Federation of Consulting Engineers (FIDIC) forms, a contractor is only obliged to carry out variations that are issued in writing by the authorised contract administrator. Verbal instructions do not carry the same contractual weight.

This matters for two reasons.

The first is payment. A variation instruction is the mechanism that entitles a contractor to additional payment beyond the original contract sum. No written instruction means no formal variation. No formal variation means the contractor carries out additional work at their own cost with no guaranteed path to recovery.

The second is liability. If a contractor carries out work based on a verbal instruction that later turns out to be incorrect, unauthorised or contrary to the approved drawings, they bear responsibility for the outcome. A written instruction shifts that responsibility to the person who issued it.

In practice, Kenyan construction sites run on verbal communication. Architects give directions during site visits. Clients call foremen directly. Project managers send WhatsApp messages that nobody files. All of this creates a paper trail gap that becomes extremely expensive the moment a dispute arises.

The standard process is simple. Any instruction that changes the scope, specification, sequence or timeline of the contracted works should be issued on a numbered Architect's Instruction form, signed by the contract administrator, and acknowledged in writing by the contractor. If a verbal instruction is given on site, the contractor should follow it up immediately with a written confirmation letter stating the instruction as understood, the date it was given and the name of the person who gave it, and send it to the architect or employer's agent for their records.

If they do not respond disputing the content of that letter, it stands as the agreed record.