Concrete and Masonry Estimated Taxes: A Nine-Month Season, a Three-Month Shutdown, and the Equipment Purchase That Changes the Number

Concrete and masonry contractors have a long season by the standards of the seasonal trades — nine months in most northern markets — and a hard stop that the estimated-tax calendar doesn't recognize. The rules (the contractor guide covers the mechanics): quarterly installments on April 15, June 15, September 15, and January 15; a quarter-by-quarter underpayment penalty; avoided by the prior-year safe harbor (100% of last year's tax, 110% above US$150,000 of prior-year adjusted gross income) in equal installments, 90% of the current year's tax in equal installments, or the annualized method matching each quarter's actual income. The season against the calendar: pours begin when the ground thaws (March or April), ramp through spring, peak in summer and early fall (the months when both residential flatwork and commercial work run full), taper in November as temperatures fall, and stop — December through February are shutdown months with no revenue, seasonal crew layoffs, and continuing fixed costs (equipment loans, insurance, the yard); so the first installment (April 15) falls at the season's start with little income yet, the second (June 15) and third (September 15) fall in the season with cash available, and the fourth (January 15) falls in the shutdown when nothing is coming in — a milder mismatch than a chimney sweep's (three installments outside the season) but with the same fourth-quarter problem: the year's last installment is due when the year's revenue has stopped. The two solutions. The prior-year safe harbor with a reserve: four equal installments of last year's tax, with the April installment funded from last season's reserve, the June and September installments from in-season receipts, and the January installment from a reserve built during the fall's billing — a percentage of every draw and progress payment moved to a tax account (for most contractors 25% to 35% of net profit, applied as a share of receipts through the business's margin — a contractor with a 22% net margin and a 32% effective rate reserves about 7% of every receipt); penalty-proof, with an April balance in a growth year and a refund in a flat or equipment year. The annualized method: installments computed from income earned through each quarter's cutoff, annualized — a small first (through March, before most pours), a substantial second (through May), a large third (through August, the peak), and a moderate fourth (through December, the taper and the shutdown) — with Form 2210 Schedule AI at filing; the method fits a contractor whose books are current (the job-cost system's monthly close) and whose spring start is late enough that the equal-installment April payment would overpay. The S corporation contractor (the entity guide): the owner's salary withholding covers the tax on salary and can be set to cover distributions — deemed paid evenly across the quarters — and a November payroll with the season-end bonus and heavy withholding cures the year, which for an S corporation contractor with a base-plus-bonus salary schedule makes the estimated-tax problem largely a withholding setting. The equipment factor — the concrete trade's distinctive swing: a skid steer, a truck, a form system, or a mini-excavator bought and placed in service during the season and expensed under section 179 or bonus depreciation (the deductions guide) can cut the year's taxable profit by tens of thousands of dollars — a contractor who paid the prior-year safe harbor's installments on last year's profit and then bought a US$60,000 skid steer in August has overpaid the year by the tax on US$60,000; the fall recompute (in October or November, when the year's purchases are known and the season's profit is largely booked) adjusts the fourth installment down — or, for a contractor who knows in March that a purchase is coming, the current-year method (90% of projected tax including the write-off) sizes all four installments to the post-equipment profit; the timing of the purchase itself is a planning lever (a November purchase placed in service before year-end lands in this year; a March purchase in next year), decided with the estimated-tax picture in view. The cash-method timing on materials: under the cash method most small concrete contractors elect, materials are deducted when paid — so a December pour paid in December is deductible this year though billed in January (the deductions guide), a year-end timing item that reduces the current year's taxable profit and that the fall recompute accounts for; a contractor who prepays a supplier's January delivery in December has moved a deduction forward (permissible within the cash method's rules for prepaid supplies used within the following year). What the estimate includes: federal income tax on projected profit; self-employment tax for Schedule C and partnership owners who materially participate (15.3% on 92.35% of net earnings, the omitted third — and for a contractor whose profit reaches the US$184,500 Social Security wage base for 2026, the rate drops to 2.9% above it); the state's estimates; and the payroll costs (crew wages, the employer's payroll taxes, workers' compensation) already in the profit projection — a contractor who has been misclassifying crew members as contractors (the classification guide) has understated costs and an exposure the estimate can't fix. The shutdown's cash plan: the January 15 installment and the owner's shutdown salary (for S corporations) both draw on the season's reserve — a reserve the contractor does not touch for the equipment loan payments or the March rehire's first payroll; the reserve account is genuinely separate, and its December balance is checked against the January installment plus the shutdown's fixed costs. The failure modes: paying the April installment in full in a year the season starts late (overpaying, cash-poor for the March payroll); skipping January because the shutdown left no cash (a fourth-quarter penalty on the year's real fall income); paying the safe harbor through an equipment year without the fall recompute (a large overpayment refunded in April — a year of interest lost); omitting self-employment tax; and spending the fall's draws on next year's equipment before reserving the tax. The calendar: January 15 — fourth installment from the fall reserve; late January — close last year, compute the safe harbor, set the reserve percentage, choose the method; March–April — pours begin; April 15 — first installment (small under annualized; from the prior-season reserve otherwise); June 15 and September 15 — installments from in-season receipts; October–November — the fall recompute (equipment, the season's actual profit, the December pour timing); reserve transfers on every fall draw; January 15 — the fourth installment; filing — Form 2210 Schedule AI if annualized.

Key takeaways

• The season runs March–November; the January installment falls in the shutdown — the fourth quarter's payment is due when revenue has stopped, and the reserve built from fall draws is what funds it.
• Prior-year safe harbor with a reserve, or the annualized method (small April, substantial June, large September, moderate January) with Form 2210 Schedule AI — the annualized method fits a late spring start.
• Equipment is the swing: a skid steer or truck expensed in season can cut the year's tax by more than an installment — recompute in the fall, or use the current-year method when the purchase is planned; purchase timing (November vs March) is a lever.
• S corporation contractors use salary withholding, deemed paid evenly — a November bonus with heavy withholding cures the year.
• Include self-employment tax and the state; the December pour paid in December is deductible this year under the cash method — account for it in the recompute.
• The reserve is separate and untouched for equipment loans and the March rehire — its December balance is checked against the January installment plus the shutdown's fixed costs.

The concrete contractor's estimated-tax calendar

January 15: fourth installment (fall reserve). Late January: last year closed; safe harbor; reserve percentage (effective rate × margin); method. March–April: pours begin. April 15: first installment. June 15, September 15: installments from in-season receipts; reserve transfers on every draw. October–November: fall recompute — equipment placed in service, the season's actual profit, December pour timing; adjust the fourth installment. Filing: Schedule AI if annualized. The recompute line is the concrete trade's own.

Worked example

A flatwork contractor (S corporation, three-person crew) projects US$190,000 of profit on a normal season; last year's tax on the owner's return was US$46,000. Plan A, the safe harbor: his salary withholding is set in January to cover last year's tax across the year's payrolls (deemed paid evenly), with 7% of every draw reserved. In August he buys a skid steer (US$58,000) and expenses it under bonus depreciation — the fall recompute in October shows the year's taxable profit at US$132,000 and the tax at about US$32,000; his November payroll's withholding is cut accordingly, and the reserve's excess funds the shutdown's fixed costs instead. The December pour on a commercial slab (US$11,000 of concrete paid in December, billed in January) is deductible this year under the cash method — in the recompute. Plan B, had he been on Schedule C: the annualized method — a small April installment (the season started in mid-April), a substantial June, a large September, and a fourth computed after the skid steer's write-off — small — with Schedule AI at filing; or the safe harbor's four equal installments with the fall recompute cutting the fourth. His competitor paid the safe harbor's full installments through September, bought a skid steer in October, skipped the recompute, and overpaid the year by the tax on US$58,000 — refunded the following May, after a winter of paying interest on the equipment loan the refund would have covered.

Official sources

The IRS states that "individuals, including sole proprietors, partners, and S corporation shareholders, generally have to make estimated tax payments if they expect to owe tax of $1,000 or more when their return is filed," and that the penalty is avoided by paying "at least 90% of the tax for the current year, or 100% of the tax shown on the return for the prior year, whichever is smaller" (110% if prior-year AGI exceeded $150,000). — Internal Revenue Service, Estimated taxes, https://www.irs.gov/businesses/small-businesses-self-employed/estimated-taxes

Publication 946 states that "this publication explains how you can recover the cost of business or income-producing property through deductions for depreciation (for example, the special depreciation allowance and deductions under the Modified Accelerated Cost Recovery System (MACRS))," and covers the section 179 election and its limits. — Internal Revenue Service, Publication 946, How To Depreciate Property, https://www.irs.gov/publications/p946

Practitioner note

Concrete contractors have a nine-month season, a hard shutdown, and an equipment cycle that swings the year's tax by more than an installment — which makes the fall recompute the trade's own step in the estimated-tax calendar. Our contractors reserve a margin-calibrated share of every draw, fund the January installment and the shutdown's fixed costs from a reserve they don't raid for the March rehire, and recompute in October for the skid steer and the December pour — because the safe harbor paid blindly through an equipment year is a refund the equipment loan could have used in January.

See also: For related guidance, see concrete and masonry business deductions; and browse every small business tax guide, by situation.

Next step

Fairlight handles estimated-tax planning for concrete, masonry, and equipment-heavy contractors — safe-harbor and annualized computations for a nine-month season, reserve rules calibrated to margin, the fall recompute for equipment placed in service and cash-method material timing, and S corporation withholding through the shutdown. See pricing or book a call.