Define the scope before adding prices
List the rooms and work packages with the intended result. Separate necessary repairs, improvements and options. Mark matters that cannot yet be priced because an investigation or design decision is missing. The budget should explain the assumptions behind its figures. Do not use a generic price per square metre as a substitute for a quotation for the actual building.
Include studies and work outside the main quotations
Check surveys, design fees, delivery, removal, protection, reinstatement and finishing. Add directly purchased items without duplicating those already included by a contractor. Consider practical expenses caused by the work, such as temporary accommodation where relevant. Assign each item to a document or an identified assumption rather than hiding it inside an unexplained total.
Keep an explicit allowance for uncertainty
Distinguish a known extra from an allowance chosen for possible discoveries. There is no universal percentage appropriate to every project. Explain which uncertainties remain and what investigations might reduce them. An allowance does not approve any extra work automatically. When a change is confirmed, move it into the actual scope and update the remaining allowance transparently.
Separate expected assistance from agreed funding
Record the status of grants, loans and your contribution separately. A simulation or an application is not a confirmed amount available for spending. Check the official process before commitment and verify conditions for the actual project. Our budget tool calculates a funding gap from your figures; it neither estimates grant eligibility nor recommends a credit product.
Check cash flow and maintain the budget
Place payments and receipts in their real order. A balanced project total may still contain a temporary shortfall. Keep dated revisions of quantities, prices and decisions so that a new quotation can be compared with the previous basis. Review commitments already made before approving a new purchase. Use the cash-flow guide for a stage-by-stage calculation and its limitations.
Your preparation checklist
- Scope and optional work separated.
- Studies and associated costs included.
- Direct purchases reconciled with quotations.
- Allowance identified as an assumption.
- Confirmed and expected funding distinguished.
- Payment dates compared with funds available.
Questions before you commit
Does this site provide a market price estimate?
The tools use your quotations and assumptions. They do not supply a universal building price.
Can I enter an unknown cost as zero?
No. Zero means no cost in the calculation. Keep the unknown item on your working list and obtain the information.
Sources and the scope of this guide
This English guide covers the same project need as its French counterpart, with an editorial explanation in English. It is not a professional survey or a translation of foreign rules to France. Check current official requirements and the documents applying to your building and contract.
French reference: France Rénov’ : bien planifier vos travaux de rénovation