Building work does not match the drawings: what should you do?
Pause the affected decision, record what was built and compare it with the current approved drawing and specification. A difference can be an agreed variation, a harmless dimensional adjustment, a design error or a serious structural or regulatory problem. Establish which it is before more work covers the evidence.
Find the controlling documents
Check the contract drawing register, revision dates, engineer’s details, specification, building control submissions and written site instructions. A builder may have worked from an older plan, while the designer may have issued a revised detail that never reached site. Put the relevant versions side by side and mark the exact location and dimension of the difference.
Record the actual work
Take dated, wide and close-up photographs with a scale where useful. Note materials, dimensions, who was present and whether the work is still accessible. Ask the builder what instruction they relied on and whether the designer or engineer approved a change. Keep the question factual; an accusatory message before establishing the revision history can make resolution harder.
Decide who must check it
A moved socket or changed finish may be a scope and price matter. A beam, bearing, fire detail, drainage fall or waterproofing change needs the appropriate technical professional to assess it. Building control may need to be informed or inspect the change. Do not accept a verbal “it’s fine” for a structural or safety-critical deviation, and do not direct remedial engineering work yourself.
Agree the remedy and account
Ask for a written decision: retain as built with documented approval, alter to the agreed design, or issue a revised design and price. Record who pays, programme impact, inspections and any warranty or certificate updates. If the change was unauthorized or defective, the contract and facts determine responsibility. Avoid paying for a variation simply because it has already been installed.
Our variation guide explains how to authorize changes, while the poor workmanship guide covers evidence and remedy. Building control approval is not a quality warranty. For a serious dispute or contract termination, obtain legal advice.
Build Advocate can organize the evidence and help identify the practical next step from the homeowner’s side, including when a structural engineer or other specialist must decide. See the Rescue Initial Assessment and other services.
