Knowledge · Finance
Cash flow forecasting for builders,
finding the hole while it can still be fixed.
Building work pays in stages and costs money continuously, so every job dips cash negative on its way to profitable. This reference covers the job-level cash curve, rolling jobs up to a company position, where the dates and amounts must come from, the stress tests worth running, and the discipline of moving the forecast every time the programme moves.
01 / Overview
What a cash flow forecast is
A cash flow forecast is a dated picture of the money a building business expects in and out, week by week, far enough ahead to act on what it shows. It is the forward-looking instrument of the wider construction cash flow discipline. The money-in side is built from the progress claims each job expects to issue and collect; the money-out side is built from committed costs falling due on their terms, plus the overheads and remittances that land regardless of what the jobs do.
The defining feature of a real forecast is where its numbers come from. Dates come from the programme, amounts come from the claim schedule and the committed costs, and the receipt dates carry the payment terms and the client's actual paying habits. A spreadsheet whose claim dates are the dates the builder would like to be paid is not a forecast, it is a hope with columns, and the difference only becomes visible at the worst possible time.
Why it matters
Building businesses rarely fail for lack of work, and a profitable job can still break the business that built it, because profit arrives over the life of the job while wages and suppliers are paid this week. Cash timing is the gap between those two facts. The forecast is the only instrument that shows the gap before the bank account does, and in a market where construction tops the insolvency count, it is the difference between a problem that gets managed and a problem that gets discovered.
02 / The lifecycle
Where the forecast sits in the workflow
The cash flow forecast is largely two other disciplines with dates attached. The cost to complete says what the remaining work will cost; the forecast places those costs on the dates they will be paid. The claim schedule says what the client owes at each stage; the forecast places those receipts on the dates they will realistically arrive. Both of those inputs are reported job by job through job cost reporting, which is why a business with weak job reporting cannot forecast cash no matter how good its spreadsheet is.
Downstream, the forecast is one of the standing instruments of financial visibility, the small set of numbers an owner should be able to see without commissioning a project. It also feeds the biggest single decision a small builder makes, whether to take the next job, because a signed contract commits the business to funding that job's dip whether or not the position can carry it.
03 / Process workflow
Building the forecast, step by step
Eight steps, from drawing each job's cash curve to correcting the assumptions against what the bank actually did. The roll-up in the middle is where job problems become company problems, or cancel each other out.
- 01
Draw each job’s cash curve
For every live job, lay out the claim schedule against the programme, deposit, stage claims and the final claim, each with the date the money should actually arrive rather than the date the invoice goes out. This is the money-in side, and every date on it comes from the programme, not from hope.
- 02
Map the committed costs to their terms
Purchase orders, subcontracts and supply agreements each carry payment terms, and the forecast places every committed cost on the date it falls due under those terms. Uncommitted remaining work comes across from the cost to complete, timed against the programme.
- 03
Add the recurring outflows
Wages, rent, insurances, vehicle and equipment costs, loan repayments, and the GST and BAS remittances that fall due on the reporting cycle. These land whether the jobs claim or not, which is exactly why a jobs-only forecast flatters the position.
- 04
Roll the jobs up to the company
Sum every job curve and the overheads into one company-level line, week by week, starting from the actual bank position. Staggered jobs can smooth each other’s dips; jobs that hit their heavy stages together compound them, and the roll-up is where that becomes visible.
- 05
Stress-test the position
Re-run the line with one claim paid a month late, one stage slipping a fortnight, and one claim disputed and removed until resolved. The question is not whether the base case works, it is which single ordinary event breaks it.
- 06
Set the horizon and cadence
A thirteen-week working horizon is a common convention, detailed week by week, with a coarser monthly view beyond it. Refresh weekly, and rework the forecast the day the programme moves, because a schedule slip moves cash even though no invoice changed.
- 07
Read the position and decide
A forecast exists for the decisions it enables, bringing a claim forward, slowing a start, arranging supplier terms, drawing or repaying a facility, or declining a job the position cannot carry. A forecast nobody acts on is administration, not management.
- 08
Compare forecast to actual and correct
Each week, compare what the forecast said against what the bank did, and correct the assumptions that missed, the client who always pays a week late, the trade who invoices early. This loop is what turns a spreadsheet into an instrument.
04 / Key mechanics
The anatomy of the job cash curve
Every residential job traces the same shape, cash in at the deposit, a sawtooth of dips and recoveries through the stages, and a tail at the end. The company position is all the live curves added together.
The deposit
The job’s opening cash, received before significant cost goes out. Deposits on residential work are capped by state legislation, so the opening buffer is thinner than the early invoices make it feel.
Stage claims in
The money-in events, each tied to a stage of the programme and each arriving only after the stage completes, the claim is issued and the payment terms run. Three separate delays stack on every one of them.
Committed costs out
Suppliers and trades are paid on their terms as the stage is built, which is usually before the claim for that stage arrives. The gap between those two timings is the whole subject of this page.
The mid-stage dip
Inside most stages the job goes cash negative, costs run ahead of the next claim and the builder funds the difference. The dip is normal; a dip deeper than the business can cover is not.
Retention and the tail
Where retention or a final-claim holdback applies, a slice of every claim arrives months after the work, so the job finishes cash-poorer than its margin suggests until the tail is collected.
The company roll-up
One job’s deposit can cover another job’s dip when starts are staggered. Two jobs hitting frame stage in the same fortnight compound the outflow, and only the rolled-up line shows which is happening.
The mid-stage dip
Inside a stage, the builder pays for frames, windows and trades on supplier and subcontract terms while the claim for that stage cannot even be issued until the stage completes. Costs run ahead of revenue, the job's cash line crosses below zero, and the builder funds the gap from the deposit, from other jobs or from a facility. How deep the dip runs is set by the spread between the claim schedule and the payment terms, which is why retention and payment terms are a cash flow instrument and not an accounts formality, and why ordering materials earlier than the programme needs (covered in aligning procurement with the schedule) deepens the dip for no construction benefit.
Stress-testing the forecast
A base-case forecast answers the wrong question, because the base case is the one future that never quite happens. The useful tests are ordinary events, not catastrophes. Re-run the line with one claim paid a month late, because one will be. Re-run it with one stage slipping a fortnight, which moves the claim behind it while most of the costs stay put. Re-run it with one claim disputed and removed until resolved. If any single one of those breaks the position, the business is not carrying a risk, it is carrying a countdown.
When the forecast says stop
The hardest reading of a forecast is the one that says the next job cannot be taken yet. A new contract arrives with a deposit attached, which makes it look like the solution to a tight position, but it also arrives with its own mid-stage dips, and those land exactly when the current jobs are still drawing cash. Taking work the position cannot carry is how the deposit-funds-the-last-job spiral starts. The open job value guide covers the measure that sits behind this decision, how much committed future work the business is already carrying, and what its balance sheet can actually hold.
05 / Best practice
How experienced builders run the forecast
The operator's observation is that the forecast's job is to be wrong early. A builder who discovers a June cash hole in March has options, bring a claim forward by resequencing a stage, slow a start, arrange supplier terms or a facility while the business still looks bankable. The same hole discovered in June has none; every one of those moves needs weeks of lead time, and by June the only options left are the phone calls nobody wants to make. Nothing about the hole changed between March and June except the number of ways out of it.
The discipline that separates operators is not building the forecast, it is moving it when the programme moves. A stage slips a fortnight and most builders record it as a scheduling matter, but the claim behind that stage just slipped a fortnight while the supplier payments mostly did not, so the dip got deeper and later. A schedule slip is a cash event wearing a time costume, and builders who re-run the forecast the day the programme moves catch it in costume. The same instinct is what the building through a downturn guide calls cash discipline, and it costs a great deal less in a forecast than in a bank account.
Where software fits the workflow
Traditionally the forecast is a spreadsheet fed by hand from the claim schedule, the order book and the bank statement, which is why it decays between rebuilds. In VIABUILD the inputs stay live, claims and committed costs come from the jobs as they run, and the Xero integration keeps invoices, payments and the actual bank position aligned with the job data instead of re-keyed from it. Oryn™ reads supplier invoices as they arrive so the outgoing side is current without chasing paper, and the builder's weekly forecast pass spends its time on judgement, the dates that moved and the claims at risk, rather than on assembling the inputs.
06 / Australian considerations
Forecasting in the Australian environment
Cash flow forecasting is an internal discipline, but the curve it draws is shaped by Australian contract law, tax timing and, at the moment, a contracting market. The points below are labelled by evidence class; figures and requirements change, so confirm the current source before relying on any of them.
- Legislation. Each state and territory's domestic building contract legislation caps deposits on residential work and regulates how stage payments may be structured, which means the shape of the money-in curve is partly set by law before the builder draws it. The rules differ by jurisdiction; confirm the current requirements with the relevant state regulator before setting a claim schedule.
- Common practice. GST collected on claims is remitted with the business activity statement on the business's reporting cycle, offset by credits on inputs, so the bank balance between BAS dates overstates what the business can spend. Forecasting in gross bank terms with the BAS remittance as a recurring outflow is the common convention. Treatments and cycles vary, so confirm the specifics with the ATO or the business's accountant.
- Statistics. A record 3,596 Australian construction companies entered external administration for the first time in FY 2024-25, up 21 per cent on the prior year, and construction tops the industry count for insolvencies. The figures move each reporting period, so confirm current numbers against ASIC's published statistics. The pattern underneath them is stable, businesses with work in hand failing on cash timing, which is the specific failure a forecast exists to prevent.
- Market forecast. The ACIF May 2026 forecasts project a 0.8 per cent contraction in total construction work done across 2026, with residential building the most exposed sector. Forecasts are revised each release, so re-check against the current ACIF publication. The practical reading for cash flow is that softer volumes make every receipt date matter more, because there is less incoming work to paper over a late claim.
- Professional recommendation. Industry commentary through the current contraction has been consistent that cash discipline matters more in a downturn, not less, and that builders who hold strong payment terms, document variations rigorously and keep their forward numbers current sit in a materially different position to those who do not.
07 / Common mistakes
Where cash flow forecasts actually go wrong
Each of these is recognisable, mechanical and avoidable. None of them requires bad numbers, only unexamined ones.
Claim dates copied from the invoice
A forecast that books the claim on the day it is issued ignores the payment terms and the client’s actual habits. Money arrives when it arrives; the forecast should carry the realistic receipt date, not the hopeful one.
The forecast not moved with the programme
The stage slips a fortnight, the claim behind it slips a fortnight, and the supplier payments mostly do not. A forecast still showing the old dates is wrong in the direction that hurts, and it stays wrong quietly.
Gross receipts treated as available
The GST component of receipts is owed at BAS time, and the bank balance in between overstates what the business can spend. Builders who forecast the remittance as a recurring outflow stop being surprised by it.
Overheads left out of a jobs-only forecast
Wages, rent and repayments land every week whether the jobs claim or not. A forecast built only from job curves shows a business healthier than the one that has to make payroll.
The bank balance used as the forecast
Today’s balance is history, the residue of decisions already made. A healthy balance the week before two jobs hit frame stage together is not health, and only a forward view can tell the difference.
The new deposit funding the old job
Taking the next job to cover the current hole works exactly once per job, and the hole it leaves is bigger. This is the spiral pattern visible in most builder insolvencies, and a rolled-up forecast is the instrument that names it early.
08 / Practical example
A worked June hole, found in March
Illustrative only, not a benchmark. A builder running three homes rolls the jobs up in March and the line dips hard in the second week of June. Two jobs hit their heaviest fortnight together, frame and lock-up packages totalling about $180,000 due out on supplier and subcontract terms, while the claims expected in that fortnight total $95,000 and wages plus a BAS remittance take roughly $40,000 more. The position runs about $60,000 past the overdraft, on paper, eleven weeks out.
Because it is March, the fix is a series of unremarkable decisions. The lock-up stage on one job is resequenced so its claim lands two weeks earlier, the third job's start is pushed back three weeks so its early costs move out of the fortnight, and the frame supplier agrees to extended terms on the largest order, asked a month in advance rather than a day. The June that eventually arrives is dull, which is the entire point. The same hole discovered in June is a missed payroll, a supplier on stop-credit and a conversation with the bank from the weakest possible position.
09 / FAQ
Common questions.
Common practice is a rolling thirteen-week working horizon, detailed week by week, with a coarser monthly view running out beyond it for start dates and the pipeline. Thirteen weeks is a convention rather than a rule; it is roughly a quarter, long enough to see the next BAS cycle and the next stage of every live job, and short enough that the dates in it can come from real commitments rather than guesses. The far end of the horizon will always be softer than the near end, and that is fine, because the purpose of the far end is early warning rather than precision.
Profit is what a job earns over its whole life; cash flow is when the money actually moves. A job can be comfortably profitable on paper and still put the business under, because the costs of a stage go out on supplier terms before the claim for that stage comes in, and the builder funds the gap. Businesses fail from running out of cash, not from a weak annual profit figure, which is why the forecast matters even in a business whose jobs all make money.
Dates come from the programme, amounts come from the claim schedule, the committed costs and the cost to complete, and the recurring outflows come from the actual overhead run rate. None of it should come from optimism. The practical test of a forecast is whether every line can answer the question of where its date and amount came from; a line that cannot answer is a hope wearing a number.
Weekly is common practice for the working horizon, plus an immediate rework whenever the programme moves or a large variation lands. The weekly pass is cheap when claims, orders and payments are already recorded, because most of the forecast rolls forward and the review only touches what changed. The event-driven update is the one builders skip, and it is the one that matters most, because a schedule slip changes the cash position even though no invoice and no price changed.
The practical convention is to forecast in gross terms, the amounts that actually hit and leave the bank account, and then carry the BAS remittance as its own recurring outflow on the reporting cycle. That way the bank line in the forecast matches the real bank account, and the tax liability is visible instead of hiding inside the balance. Reporting cycles and treatments vary between businesses, so confirm the specifics with the ATO or the business’s accountant rather than a web page.
Be glad it showed up in the forecast and not in the bank account, then use the time. The standard moves are bringing a claim forward by resequencing work so a stage completes earlier, slowing or deferring a start so its costs land later, arranging extended terms with a major supplier before the money is owed, arranging a facility while the business still looks bankable, and chasing the receivables that were being politely ignored. Every one of those options needs weeks of lead time, which is the whole argument for the forecast.
10 / Terms
Glossary for this topic
Cash flow forecast (the dated forward view of money in and out), job cash curve (one job's cumulative cash position over its life), the dip (the negative stretch where costs run ahead of the next claim), claim schedule (the contracted stages and amounts a job will claim), committed cost (money promised by an order or subcontract but not yet paid), working horizon (the detailed near period of the forecast, commonly thirteen weeks), BAS remittance (the periodic payment of GST and other obligations to the ATO). Definitions for the wider vocabulary live in the construction glossary.
The forecast is one instrument on a larger panel, and what the rest of that panel should show an owner is the subject of financial visibility in a building business.
11 / Keep reading
Related knowledge, guides and features
12 / Further reading
Primary sources
- Australian Taxation Office , the reference for GST reporting cycles and business activity statement obligations.
- Australian Securities and Investments Commission , publisher of the insolvency statistics behind the external administration figures, the reference for current numbers.
- Australian Construction Industry Forum , publisher of the national construction forecasts describing the market a cash position operates in.
- Your state or territory's building regulator and fair trading body, for the deposit caps and stage payment rules that shape a residential claim schedule in your jurisdiction.
See the hole in March, not in June.
VIABUILD keeps claims, committed costs and the Xero bank position on one understanding of every job, so the cash forecast is a live instrument the business steers by, not a spreadsheet rebuilt after the programme has already moved.