Planning a renovation budget, including the unknowns

Combine the brief, available survey findings and key work items, identifying retained, replaced and unassessed elements. If scope is incomplete, request an estimate with assumptions rather than a final price.

Compare quotations by category. An omitted item is not necessarily free or unnecessary. Use the BOQ article to examine quantities, specifications and exclusions instead of selecting the lowest total alone.

List relevant design and specialist fees, inspections, construction, furniture, appliances and occupancy-related costs. Include what applies to the project, not an automatic charge for every category.

Confirm whether tax, delivery, waste removal and cleaning are included. Avoid double counting. Unknown costs need a separate line with an owner and decision date.

If a sink or appliance is needed but no model is selected, identify a provisional allowance, quantity and inclusions. Update it when the selection is confirmed, including service or cabinetry effects.

Terms such as allowance and provisional sum depend on the documents. Define what the amount covers and how it changes. Known undecided purchases should not disappear into contingency.

Ask the team to assess unknowns, such as concealed conditions or unresolved coordination. Separate these from optional additions. There is no fixed contingency percentage here because scope and information differ by house.

AIA discusses uncertainty and scope adjustment in a US contractual context, not Thai contract law. Use it as discussion context, then agree a project-specific contingency and update the balance when spending is authorised.

Track category / estimate / committed amount / paid amount / remaining amount, plus pending prices. Commitment is not payment; remaining funds should reflect agreed obligations, not just the bank balance.

Before changing materials or adding work, request written cost and schedule effects. If the plan exceeds the ceiling, revisit priorities and appropriate deferrals rather than consuming contingency without an explanation.