Cash flow is the oxygen of a trade business. Run out of it — even temporarily — and everything seizes up. You can't pay your subbies, can't buy materials, can't cover your own wage. And the frustrating truth is that this happens to profitable businesses all the time.
The problem isn't income — it's timing. Understanding and controlling the timing of money coming in and going out is the core skill of running a successful trade business.
Why Profitable Tradies Still Run Out of Cash
Here's a scenario that plays out constantly in the NZ construction industry:
You win a $80,000 renovation job. You buy $25,000 in materials upfront (you pay the merchant 30 days). You invoice the client in stages. The first progress invoice for $20,000 is issued — but the client pays 30 days later. Meanwhile your merchant account is due. Your subbies want to be paid. Your own drawings need to come from somewhere.
On paper, the job is profitable. In practice, you've got $0 in your account for six weeks.
This is a cash flow problem, not a profit problem. The solution is to restructure how and when money moves.
Strategy 1: Deposits Before You Start
For any job involving significant materials — renovations, roofing, kitchens, bathrooms, electrical — collect a deposit before ordering materials or starting work. Standard practice in NZ is 20–50% upfront.
What this does: - Funds your materials purchase without debt - Confirms the client is serious (non-paying clients often disappear at deposit stage) - Reduces your exposure if the job falls over
A simple clause in your quote: "A 30% deposit is required to secure this booking and order materials. Work commences upon receipt of deposit."
Our Quote Template has space for payment terms including deposits.
Strategy 2: Invoice the Moment the Work Is Done
The most common invoicing mistake: doing the job on Monday, sending the invoice at the end of the month.
You've just given the client an extra 2–3 weeks to pay before the clock even starts. If your terms are 14 days from invoice, and you invoice three weeks late, you're waiting five weeks to be paid.
Invoice the day the work is complete — or the same evening. Most job management apps (Tradify, Fergus, NextMinute) let you create an invoice from your phone on-site. If you don't have one, email a PDF invoice from your phone using our free Tax Invoice Template.
Strategy 3: Shorten Your Payment Terms
The construction industry has a habit of 30-day payment terms inherited from commercial practices. But for residential work and smaller trade jobs, there's no reason you can't ask for payment in 7 days.
The data backs this up: shorter payment terms consistently result in faster payment. Clients don't push back — they just pay when the terms say to pay.
Consider: - Residential / small jobs: 7 days from invoice - Commercial / larger contracts: 14 days from invoice - Major construction contracts: 20 working days (CCA default)
State your terms clearly on every invoice and in your quote/contract. Clients who know when payment is expected are more likely to pay on time than clients who see "terms: 30 days" and interpret it as 60.
Strategy 4: Progress Payments on Larger Jobs
For any job running longer than 3–4 weeks or worth more than $20,000–$30,000, invoice in stages rather than at the end. Typical milestones:
- On acceptance / deposit: 30%
- Practical completion of Stage 1 (e.g., framing): 30%
- Practical completion of Stage 2 (e.g., pre-line): 25%
- On completion / sign-off: 15%
This keeps cash flowing throughout the job rather than having one large invoice at the end that takes another month to be paid.
Our Progress Claim Template and CCA Payment Claim Template are formatted for this structure.
Strategy 5: Separate Your Tax Money
One of the most dangerous cash flow traps: spending money that was never yours to spend.
Every time you invoice, set aside 25–30% immediately in a separate bank account for: - Income tax (provisional instalments + terminal tax) - GST collected (paid to IRD on your return dates) - ACC levies
This money isn't your profit. It belongs to IRD. The tradies who get into real trouble are those who run down their account before a provisional tax date and suddenly owe $12,000 they don't have.
A separate account labelled "Tax" that you never spend from is the simplest and most effective financial habit you can build.
Strategy 6: Build a Cash Buffer
How much cash should your business hold in reserve? A common benchmark: 1–2 months of total operating expenses (wages, rent/lease, insurance, loan payments, average materials spend).
For a sole trader spending $8,000/month, that's $8,000–$16,000 sitting in reserve doing nothing productive — but that's the cost of not having a crisis when a big client pays late.
Build the buffer over time by paying yourself a fixed weekly wage and leaving surplus in the business account until the reserve is funded.
The GST Timing Trap
Here's a specific cash flow trap that catches GST-registered tradies: you collect 15% GST from clients as part of your invoices. But you don't pay it to IRD until your return is due (typically every 2 months).
In the meantime, that GST is sitting in your account. It looks like your money. It isn't. Many tradies spend it, then struggle to cover their GST return.
Fix: The separate tax account above should include the GST you've collected. When the return is due, the money is ready.
Key Takeaways
- Cash flow problems happen to profitable businesses — it's about timing, not income
- Collect a deposit before ordering materials (20–50% depending on the job)
- Invoice the day work is done — not at the end of the month
- Shorten payment terms — 7 days for residential work is standard and reasonable
- Use progress payments for jobs longer than 3 weeks
- Set aside 25–30% of income immediately for tax and GST — it's not your money
- Build a 1–2 month cash buffer to survive late payers
Use our free Job Cost Calculator to track margins and our Progress Claim template for stage invoicing on larger contracts.
NZ Tradie Tools provides free calculators, templates, and guides for New Zealand tradies. For complex cash flow situations or business financial planning, consult a business accountant.