Start with the same work packages
Break the proposal into recognisable areas such as structure, facades, electrical work, plumbing and finishes. Check what area or quantity each price refers to. A lump-sum offer also needs an understandable description of its scope.
Read the specification behind the number
A heading such as bathroom renovation does not explain whether removal, waterproofing, plumbing, fixtures and installation are included. Identify exact products or the assumptions used where selections have not been made.
Discuss access and supporting work
Lifting, scaffolding, transport, protection, disposal and temporary arrangements can change the cost. Confirm the treatment of taxes and the responsibilities for permits or approvals. International proposals should also identify the currency, destination, local interfaces and logistics assumptions.
Connect payments to defined milestones
Understand what is expected at each stage and which purchases have long lead times. Payment arrangements, inspection and acceptance should be considered together with the written programme.
Make exclusions and changes visible
A clear offer explains both what it includes and what remains outside the scope. If a concealed condition or a new requirement emerges, the proposed change and its effect on cost and timing should be reviewed before that work begins.