Last updated: March 2026 | 8 min read
Construction businesses fail more often from cash flow timing than lack of profit. Effective cash flow management requires progress claim forecasting, retention release scheduling, structured supplier terms, and accurate PAYG and GST liability forecasting. Implementing a 3-way forecast (profit and loss, cash flow, and balance sheet) gives builders visibility across every project.
In our experience working with Melbourne builders, we see a pattern that surprises many tradies. Your business might be making great profit margins, jobs might be priced well, and the workload might be strong. Yet somehow you still run out of cash mid-month.
This isn't a pricing problem. It's a timing problem. And it's why construction businesses fail at higher rates than other industries.
Revenue recognition vs cash receipt timing mismatch, retention holdbacks, material pre-purchasing, subcontractor payment cycles create a cash timing gap even when profit margins are strong.
Construction doesn't work like a cafe, where the customer pays before they receive the coffee. In the building and construction industry, the cash flow cycle is inverted. You often spend cash weeks or months before you receive it.
Here's how it typically happens:
According to ASIC insolvency statistics, construction recorded 2,975 insolvencies in 2023-24 across Australia â the highest number of any industry sector. Many of these failures were driven by liquidity pressure and timing mismatches, not reported profit alone.
One Melbourne building company we worked with was billing $40,000 per month and showing a 35% gross margin on their P&L, yet they couldn't pay their team. Why? Because they had $180,000 sitting in retention and materials on site that hadn't been invoiced yet. Their accountant looked at the profit. They needed to look at cash.
Integration of P&L, cash flow, and balance sheet projections into one connected model that shows where money is tied up and when it arrives.
Most builders use a simple cash flow spreadsheet. It shows money in, money out, and the balance. That's better than nothing, but it's not enough.
A 3-way forecast connects three financial statements:
When you connect these three, you can see the real picture. A job might be profitable on the P&L, but holding $80,000 in retention on the balance sheet. The cash flow forecast shows you exactly when that retention will hit your bank account.
For progress-claim businesses like construction, this is essential. Because, unlike retail, where you invoice once and collect once, you might invoice the same job 8 times across 12 months, with retention released 30 days after practical completion.
Learn more about how 3-way forecasting works in our 3-way forecasting for SME growth guide, and see how it applies to your business model in our business advisory forecasting services.
To get started, download a free cash flow template from business.gov.au to begin tracking your timing.
Map payment milestones to cost schedule, factor retention timing, plan for variations, and align subcontractor payment terms with progress claim receipt.
Here's a step-by-step approach to forecasting cash flow on a project level:
Start with your project timeline and the actual cost profile. When will you spend money on labour, materials, and subcontractors? Month by month. Don't guessâuse your project management data or your quotes.
When will you invoice? Most construction uses progress claims. If you have a $400,000 job over 12 months, you might invoice $30,000-$40,000 per month as the work completes. Map that schedule on a month-by-month basis.
If 5% retention is withheld, you'll only receive 95% of your progress claim. When is that retention released? Usually 30 days after practical completion, sometimes longer. Add a line in your forecast showing when that retention cash arrives.
What payment terms does your client offer? Net 14? Net 30? Net 45? Some main contractors pay slower. Build that into your forecast. If you invoice on the 1st and payment arrives on the 30th, that's a 30-day gap your cash needs to bridge.
When must you pay your subs and suppliers? Often weekly or fortnightly. Those payments might come before progress claim revenue arrives. Your forecast shows the gap.
$400,000 residential renovation, 12-month timeline:
| Month | Costs | Progress Claim | Retention (5%) | Cash Received | Net Cash |
|---|---|---|---|---|---|
| Month 1 | $15,000 | $35,000 | $1,750 | $0 | -$15,000 |
| Month 2 | $18,000 | $35,000 | $1,750 | $33,250 | $15,250 |
| Month 12 | $10,000 | $25,000 | $1,250 | $23,750 | $13,750 |
| Month 13 (Retention Release) | $0 | $0 | $0 | $20,000 | $20,000 |
Notice Month 1: you spend $15,000 in costs but receive $0 in cash. Your cash forecast shows you need $15,000 to bridge that gap. By Month 2, the progress claim arrives and cash flow improves. But in Month 13, you're still waiting for $20,000 in retention.
Without this forecast, you'd be surprised. With it, you can arrange finance or adjust your job schedule ahead of time.
For more guidance on managing cash flow during construction, see the QBCC guide on managing cash flow for builders.
The RBA's cash rate directly impacts your finance costs. When rates rise, the cost of bridging cash flow gaps increases.
0% 1% 2% 3% 4% 5% Jan 2019 Jan 2020 Jan 2021 Jan 2022 Jan 2023 Jan 2024 Jan 2025 Mar 2026 RBA Cash Rate Movement Source: RBA Statistical TablesInterest rates rose sharply from May 2022 to November 2023 (0.10% to 4.35%), eased modestly through mid-2025, then reversed with two hikes in early 2026 bringing the cash rate to 4.10%. Elevated rates increase the cost of working capital finance, making cash flow forecasting even more critical for construction businesses.
Retention is one of the biggest cash flow drains in construction. Under typical contract terms, retention is commonly 5% of the progress claim value, sometimes up to 10% on larger projects. The main contractor holds that money as security until practical completion (and often for 30 days after). Rates vary by contract â always check your specific terms.
If you're billing $400,000 on a project, 5% retention means $20,000 of your money is locked up until the job finishes plus 30 days. That's working capital you're financing with no return.
For detailed guidance on progress claims, see Master Builders guidance on managing cash flow and claims.
Our team of CPAs in Melbourne specialises in construction cash flow. We'll help you build a forecast that works.
Get in TouchPAYG and GST obligations create another timing gap. You collect GST from your client (or you're entitled to input tax credits), but you need to pay it to the ATO monthly (via BAS) or quarterly, depending on your turnover and reporting cycle.
GST timing depends on whether you report on a cash or accrual basis. Under the accrual method, GST is generally attributable on the earlier of invoice or payment (A New Tax System (Goods and Services Tax) Act 1999, s.29-5). Under the cash basis, GST is recognised when payment is received. Construction contracts may also fall under progressive or periodic supply attribution rules, which affect when GST on progress claims becomes reportable.
In practice, if you report on an accrual basis and issue a progress claim this month, GST is attributable now â even if the client pays 30 or 45 days later. Builders on a cash basis have more aligned timing, but must still forecast the liability as payments arrive.
The ATO calculates PAYG instalments using either the instalment rate method (applied to current period income) or the instalment amount method (a fixed amount based on prior year tax), as set out in ITAA 1997 Div 45. If you have a strong year, the instalment amount method may understate your liability, leaving a balance at tax time. If income drops, you may overpay and receive a refund. Either way, forecast it month by month so you're not caught short â and review your method annually with your adviser.
Note that businesses with GST turnover of $20 million or more must report monthly. Most builders below that threshold report quarterly, though you can elect to report monthly for tighter cash flow control. Monthly BAS is due by the 21st of the following month; quarterly BAS follows ATO activity statement due dates.
One common mistake: builders spend GST money on operations and then can't pay the ATO. The best practice is to quarantine GST in a separate offset account linked to your operating account. Every time you collect GST, move it to the offset account. When BAS is due, the money is there.
As a common advisory trigger, once turnover exceeds $1 million or you're running multiple projects with different retention schedules, it's worth engaging a CPA to build a proper tax and GST forecast. This is not a regulatory threshold â it's the point where complexity typically outpaces a spreadsheet. Expect to invest $2,000-$5,000, which generally saves far more in ATO penalties and finance costs.
Learn more about how we manage BAS and IAS accounting for construction businesses in Melbourne. For ATO guidance, see the ATO page on PAYG instalments and BAS obligations.
Construction insolvencies spiked in 2022-23 as interest rates rose and retention timing pressured cash flow. Even strong builders need cash flow discipline.
0 500 1,000 1,500 2,000 2,500 2019-20 1,780 2020-21 1,200 2021-22 1,450 2022-23 2,680 2023-24 2,975 2024-25 2,890 Construction Insolvencies Trend Source: ASIC Insolvency StatisticsThe jump in 2022-23 coincides with RBA rate rises and retention timing pressures. Many of these failures were driven by liquidity pressure and timing mismatches rather than lack of reported profit.
Capsule: Debtor days blowout, increasing WIP, declining gross margin per job, reliance on new contract deposits, accumulating ATO debt signal cash trouble ahead.
Cash flow stress doesn't appear overnight. It builds gradually, and the signs are visible in your monthly numbers. Here's what to watch:
Calculate your debtor days: (Accounts Receivable / Revenue) Ã 365. If this was 45 days last year and is now 70 days, clients are paying slower. This is a cash timing problem waiting to happen.
WIP is unbilled workâretention, variations, materials on site. If WIP as a percentage of annual revenue is rising (e.g., from 15% to 25%), you're financing more work out of pocket.
If margins drop from 35% to 28%, you're bidding lower or bleeding costs. This reduces the cash cushion for timing gaps.
If you can't pay your team each week without a new deposit coming in, you're essentially pyramiding cash. One slow contract will break the chain.
Are you behind on BAS payments or PAYG instalments? This is the red flag. The ATO will pursue debt aggressively, and interest accrues fast.
If you see these signs, don't wait. Engage a CPA or business advisor immediately. Many of these problems are fixable with forecasting and a cash flow restructure plan. They become impossible if you wait until the bank is calling.
Our small business bookkeeping services in Melbourne include cash flow monitoring. We track these metrics for you monthly. And if you need help, see the ASIC page on early warning signs.
A 30-minute discussion with a CPA will identify cash flow gaps you might be missing. Let's build a plan that works.
Schedule a ReviewCash flow management for builders isn't complex, but it's critical. The fundamentals are:
The builders we work with who implement these practices rarely run out of cash, even when they're growing fast. They have visibility. They make decisions from data, not surprise bank statements.
If you work in construction and want to explore how a 3-way forecast could work for your business, we're here. Our team has spent over 20 years working with Melbourne builders, and we understand the timing gaps that hurt cash flow. Let's talk.
Learn more about CPA services for builders and tradies in Melbourne.
Retention. If you have $400,000 in revenue but 5% retention is held, you don't receive $20,000 until practical completion plus 30 days. Many builders don't forecast this, so they're surprised when the bank account doesn't match the invoice total.
At minimum, monthly. Better practice is to build a rolling 13-week (quarterly) cash flow forecast that updates each week. This captures the detail of timing changes as jobs progress.
A 3-way forecast connects profit and loss, cash flow, and balance sheet projections. A job can be profitable (P&L) but tie up cash in retention (balance sheet), creating a cash flow problem. Seeing all three together gives you the full picture.
Under standard contract terms, retention is commonly 5-10% of progress claims, held until practical completion plus 30 days. This money belongs to you but isn't available to use. Over a year, $20,000 in retention is $20,000 you can't spend on overheads or next month's supplies.
As a common advisory trigger, once turnover exceeds $1 million, you're running multiple concurrent projects, managing complex retention schedules, or struggling to pay your team on time, it's worth engaging a CPA. This isn't a regulatory threshold â it's the point where a proper forecast and action plan typically pay for themselves. Expect to invest $2,000-$5,000, which generally saves far more in avoided penalties and finance costs.
42 Advisory is a CPA firm in Melbourne specialising in cash flow, forecasting, and business advisory for construction, trades, and small businesses. We've helped over 200 builders implement 3-way forecasting and avoid cash flow crises. If you want to understand your numbers, we're here to help.
Disclaimer: This article is for educational purposes only and is not financial or tax advice. Construction and cash flow circumstances vary widely. Consult a qualified CPA or accountant before implementing changes. 42 Advisory does not accept liability for decisions made based on this article.