It is the understanding that acceptance at concept design stage (RIBA 3) that the Employer only becomes liable for changes in design once they have accepted RIBA 4. All changes in design are at the contractors risk until the point at which the final design is accepted.
Can you please confirm if this is the case?
Irrespective of the stage of the project, any design changes that are made to comply with the Works Information are at the Contractor’s risk under the contract. This is confirmed in clause 14.1. The responsibility for providing the works in accordance with the Works Information(Clause 20.1) remains with the Contractor whether or not the design has been accepted.
However if a change to the design is required because the Works Information has been changed, then in this situation, the Contractor’s costs and time can be recovered through the compensation event process.