A profitable fitting job can still create a cash shortage when frames must be paid for before the customer pays the final invoice. A short rolling forecast helps expose those timing gaps before they affect suppliers, wages or tax.
This guide is written for Scottish trade readers. Check the current position against Business Gateway cash-flow support, Small Business Commissioner payment guidance and GOV.UK late commercial payment guidance; project and business circumstances can change the answer.
Forecast timing, not only profit
List expected receipts and payments by week. Include deposits, balance payments, frame orders, glass or hardware extras, subcontract labour, fuel, VAT and tax reserves. For related practical context, see trade casement windows.
Match customer stages to supplier commitments
Set lawful, clear payment stages that reflect when major costs arise. Do not promise installation dates until product and access dependencies are understood. The existing guide to pricing window fitting work helps connect the decision to job costing.
Keep a buffer and scenarios
Model a delayed customer payment, remade unit or weather interruption. A forecast is most useful when it shows how much room the business has if the optimistic date slips. It is also worth reviewing setting up a window trade account before committing to recurring supply.
Review debt before it becomes old
Issue accurate invoices promptly and follow a consistent reminder process. Disputed scope should be separated from undisputed amounts where possible.
Working checklist
| Week | Expected in | Expected out |
|---|---|---|
| Order week | Customer deposit | Supplier deposit or pro-forma |
| Pre-installation | Agreed stage payment | Labour and delivery preparation |
| Completion | Balance invoice | Making good and subcontractors |
| Following weeks | Late receipts if any | VAT, tax and overheads |
Next step
Confirm the project facts in writing before relying on a general guide. Trade Windows Scotland supplies made-to-measure windows to trade customers; the related Clyde Windows uPVC window service provides additional affiliated service context.
This article provides general business information, not tax, accounting or legal advice. Check current official guidance and obtain advice for your circumstances.
Build a 13-week forecast from actual commitments
Start with today’s reconciled bank balance, then list receipts and payments in the week they are realistically expected to clear. Include customer deposits, staged invoices, retention or disputed amounts; supplier deposits and balances; subcontractors; wages; fuel; rent; finance; VAT and tax reserves. Do not spread a large frame order evenly across the month if the supplier takes payment on one date.
Use a base case and a downside case. The downside might move one installation by two weeks, delay a commercial invoice or require a remade sealed unit. The lowest weekly closing balance shows when action is needed. Update actual figures weekly and roll the horizon forward so the forecast remains a control tool rather than a one-off spreadsheet.
Match payment stages to procurement risk
Set clear, lawful payment stages in the customer contract and explain what each stage triggers. A deposit can support survey and ordering, an interim payment can align with delivery, and the balance can follow defined completion. The exact structure must suit the customer type and contract; consumer terms must be fair and transparent. Never disguise working-capital pressure with an unexplained demand for payment.
Confirm supplier terms before promising the customer’s programme. Record order cut-offs, deposit requirements, balance dates and the consequences of a variation. If the business pays for bespoke frames weeks before installation, the quote should reflect both that funding gap and the risk of cancellation or access delay.
Protect tax and margin from everyday spending
Move an appropriate share of receipts into separate VAT and tax reserves and reconcile those balances to the bookkeeping. VAT collected is not sales margin. CIS deductions can reduce cash received without reducing reported turnover, and customer deposits may fund future materials rather than current drawings. Make those distinctions visible in the forecast.
Review estimated versus actual gross margin when each job closes. Investigate remakes, extra labour, unpriced making good and repeated travel. Cash pressure is often a symptom of underpricing or uncontrolled variations, not simply slow customers. Correct the operational cause as well as arranging short-term funding.
- Weekly closing bank balance
- Committed supplier payments
- Debtors by expected receipt date
- VAT and tax reserves
- Jobs with unbilled work or disputed variations
Use an escalation plan before the balance turns negative
First accelerate actions within the business: invoice completed stages immediately, resolve documentation queries, chase overdue accounts and defer non-essential purchases. Speak to suppliers early if timing needs to change; silence after a missed payment damages trust. If funding is required, compare total cost, security, repayment timing and the effect of a delayed job rather than choosing only by headline rate.
Record the trigger for action—for example, a forecast falling below the buffer needed for one payroll and tax payment. Agree who reviews it and what they can authorise. A lender or adviser will expect credible forecasts, recent accounts, bank evidence and an explanation of how the underlying gap will close, so maintain those records before the need becomes urgent.