How to plan for project-based cash flow

Success in construction isn't just about the quality of your build; it's about the timing of your cash. To avoid a "cash crunch," you must ensure that your outgoings—like paying for bricks, timber, and subcontractors—do not outpace your client's stage payments. Mapping these movements against a project timeline is the only way to ensure your bank balance remains healthy from the first spade in the ground to the final handover.

1. Understand the Construction Payment Cycle

Unlike a retail business where you get paid instantly, construction projects have a staggered payment structure. To plan effectively, you need to forecast four main types of "incomings":

• Deposits: Collected before work starts to cover initial material orders and mobilisation costs.
• Stage Payments (Valuations): Regular payments made at specific milestones (e.g., "wind and watertight" or "first fix complete").
• Final Payment: The remaining balance paid upon practical completion.
• Retentions: A common industry practice where the client holds back a percentage (usually 5%) of the total contract value for 6 to 12 months to ensure you return to fix any defects.

2. Map Your Project Milestones

Create a simple table or spreadsheet for every project. List every week of the build and estimate exactly when money will leave your account and when it will return. A typical project forecast might look like this:

Project Week	Activity	Outgoings (Materials/Labour)	Incomings (Client)	Net Cash Position
Week 0	Contract Signed	£0	£5,000 (Deposit)	+£5,000
Week 2	Groundworks/Materials	£7,500	£0	-£2,500
Week 4	First Stage Complete	£2,000	£8,000	+£3,500

3. Manage the "Gap"

The "gap" is the period where you have paid your "subbies" (subcontractors) and suppliers, but the client hasn't paid your stage invoice yet. To manage this:

• Negotiate Supplier Terms: Try to get 30-day credit accounts with builders' merchants so you can finish a stage and get paid by the client before the material bill is due.
• Align Subbie Payments: Try to pay your subcontractors after you have received the relevant stage payment from the client.
• Pro-forma Invoicing: If a specialist item (like bespoke windows) requires a 100% upfront payment, ensure the client pays for this specifically before you place the order.

Pro Tip: Always assume a client will pay 7 to 14 days later than agreed. If your cash flow plan only works if the client pays on the exact day of the invoice, you are at high risk of a "black hole" in your finances.

4. Account for Retentions

Retentions are the biggest "silent" killer of construction cash flow. If your profit margin on a job is 10%, but the client holds 5% as retention for a year, half of your profit is locked away. Never include retention money in your budget for day-to-day running costs. Treat it as a "bonus" for the following year once the defects liability period has passed.

5. Keep a "Buffer" Fund

Construction projects rarely go exactly to plan. Weather delays, material shortages, or unexpected site conditions can push back a stage payment by weeks. Aim to keep a "project buffer" in your business account—ideally 10-20% of the project's value—to keep the lights on and the workers paid during these inevitable lulls.