Architecture and Engineering Firm Deductions: The Software, the Sub-Consultants, the Professional Liability, and the 179D Allocation

Design firms are professional practices whose product is drawings, and the return follows the hours and the software. The people — the largest line: architects and engineers (licensed and unlicensed), designers, drafters and BIM technicians, project managers, and the administrative staff on payroll (a designer working the firm's projects on the firm's schedule with the firm's software is an employee under every test — the carpet cleaning classification guide), with the licensed professionals' registrations, the continuing education the licenses require (deductible — maintaining skills; the state boards' hours), the professional society dues (the political portion excluded), the exam fees for staff pursuing licensure (the qualifying-versus-maintaining line — a firm paying an employee's licensure exam is providing an educational benefit, deductible to the firm and excludable to the employee only through a written section 127 plan (US$5,250 a year, indexed from 2027 under the 2025 law, which also made the student-loan payment option permanent) — and exam fees sit at the edge of what section 127 covers, so many firms run them through payroll absent their adviser's sign-off), and the health, retirement, and paid-time-off costs; the utilization rate (billable hours over total hours) and the net multiplier (net revenue over direct labor) are the firm's diagnostics, and both come from the timekeeping the payroll and the billing share. Sub-consultants — passed through: the structural, mechanical, electrical, civil, landscape, and specialty consultants an architect engages on a project (or the architect an engineer engages) — genuine independent firms with their own licenses and insurance (a W-9 and a 1099-NEC where the sub-consultant is not incorporated, for payments of US$2,000 or more for payments made in 2026 (US$600 before); certificates of insurance on file), with the sub-consultant's fee a project cost and the firm's markup (if any) as revenue on a separate line; a firm that nets the sub-consultant's fee against its billing understates both. Reimbursables: printing and plotting, travel to the site, renderings and models, permit fees advanced for the owner, and the specialty studies — billed to the client at cost or with a markup — revenue when billed and paid, expense when incurred, on separate lines (never netted); a reimbursable advanced for the client and repaid at cost is close to the law firm's advanced-cost logic, but design firms customarily treat reimbursables as revenue and expense rather than as loans (the consistency of the treatment is what matters). Software — the second-largest non-labor line: the design and documentation platforms (BIM and CAD — per-seat annual subscriptions in the thousands per user), the analysis and engineering software (structural, energy modeling, civil design), the rendering and visualization tools, the project management and collaboration platforms, the specification software, the timekeeping and billing system, and the cloud storage and the IT stack — subscriptions expensed as paid (the older perpetual licenses were capitalized and amortized; the subscription model made them expenses), with the hardware (workstations powerful enough for BIM, large monitors, plotters, VR equipment for client walkthroughs) under the de minimis election or section 179. Professional liability — priced for the buildings: the firm's errors-and-omissions policy (claims-made — the premium is a percentage of fees, rising with the project types: condominiums, schools, and hospitals carry the highest rates; a firm's claims history and its contract practices, such as limitation-of-liability clauses, move it) with the tail on dissolution or a principal's retirement; general liability; workers' compensation (an office rate, with the field visits as the exposure); the cyber policy (the firm's models are a client's intellectual property); and the project-specific policies some owners require — all deductible. The office: rent (a design firm's studio — the open plan, the materials library, the model shop), the build-out as qualified improvement property (the leasehold improvements guide — a design firm designs its own space and expenses it), the furniture, and the model shop's equipment (the laser cutter, the 3D printers — section 179 or de minimis). Marketing and business development: proposals and qualifications packages (the time is the cost — RFP responses are unbilled hours), the website and the portfolio photography (a professional photographer's images of completed work — a marketing cost, with the photographer's licensing terms), the awards submissions, the conferences and the speaking, the client entertainment at zero and the meals at 50 percent, and the competition entries (design competitions — the hours and the boards are marketing costs; a prize is income). The 179D allocation — the profession's own deduction: section 179D allows a deduction for energy-efficient commercial building property (the lighting, HVAC, and envelope systems that meet the efficiency standard — with the per-square-foot amount — for taxable years beginning in 2026, US$0.59 rising to US$1.19 with savings above 25 percent, or US$2.97 to US$5.94 where the prevailing-wage and apprenticeship rules are met — and the certification requirements set by the statute) — and for buildings owned by tax-exempt entities and government bodies (schools, universities, municipal buildings, hospitals, military facilities), which cannot use the deduction themselves, the owner may allocate it to the "designer" — the architect, the engineer, or the contractor primarily responsible for the design of the energy-efficient property — through a written allocation letter; a firm that designs public buildings has claimed six- and seven-figure deductions this way, with the certification by a licensed engineer or contractor using the required modeling and the allocation letter from the government owner as the documentation, and the deduction reducing the firm's basis (zero, for a designer — the deduction is pure) — subject to the statute's termination (P.L. 119-21 ended section 179D for property whose construction begins after June 30, 2026 — a firm with public projects under way checks each project's construction start against that date). Research credits: a firm developing new design methods, computational tools, or novel structural or energy solutions may qualify for the research credit (the consulting deductions guide's mention — the design profession's claims have been contested, and the documentation of the technical uncertainty and the process of experimentation is the whole case). Contracts and revenue timing: design fees are billed by phase (schematic, design development, construction documents, bidding, construction administration — percentages of the total fee at each milestone) or hourly against a not-to-exceed — cash-method firms (most small and mid-sized firms under the gross receipts threshold) recognize the fee when paid; accrual firms recognize it when billed (with the percentage-of-completion method for the largest firms — the general contractor deductions guide's method question in a design setting); retainers and the construction administration phase's fees arrive over a project that may span years. Entity and the QBI exclusion: architecture and engineering are expressly excluded from the specified service trades (the statute names them as exceptions — the SSTB guide), so the QBI deduction applies at every income level subject to the wage-and-property limitation, which a firm's payroll satisfies — the reason a design firm's owners keep a deduction their lawyer and accountant neighbors lose (the architecture entity guide). Sales tax: design services are exempt nearly everywhere; the reimbursable printing and models are sometimes taxable as tangible property; the software subscriptions carry sales tax in the states that tax SaaS (the digital products sales tax guide); and the plotter and hardware purchases carry tax at purchase. The bookkeeping: revenue by project and phase with the sub-consultants and reimbursables on separate lines; timekeeping by project (the utilization and multiplier diagnostics; the research credit's documentation); payroll with the licensure and CE costs; sub-consultant W-9s, certificates, and 1099s; the software by seat; professional liability by project type; the 179D file (allocation letters, certifications, construction start dates); the build-out and equipment on the schedule. The errors: sub-consultants netted against billings; reimbursables netted; the 179D allocation never requested from a public owner (the deduction the owner can't use and the firm didn't claim); the perpetual-license capitalization habit applied to subscriptions; the RFP hours booked as project costs; and the professional liability premium's project-type rating misreported.

Key takeaways

• People are the largest line — designers and engineers are employees; licensure, CE, and society dues (less the political portion) are deductible; utilization and the net multiplier come from the timekeeping.
• Sub-consultants and reimbursables are passed through on separate lines, never netted — sub-consultants with W-9s, certificates, and 1099s; reimbursables as revenue and expense.
• Software is the second-largest non-labor line — per-seat subscriptions expensed as paid; BIM workstations and the model shop's equipment under de minimis or section 179; the studio build-out as QIP.
• Professional liability is priced by project type and claims history, with the tail at dissolution; cyber protects the models.
• Architects and engineers are excluded from the specified-service list — the QBI deduction survives at every income, supported by the firm's payroll.
• The 179D allocation is the profession's own deduction: designers of energy-efficient government and tax-exempt buildings can be allocated a deduction the owner can't use — with the allocation letter and the certification as the file, and each project's construction start checked against the June 30, 2026 cutoff.

The design firm's deduction file

Revenue by project and phase; sub-consultants and reimbursables on separate lines. Timekeeping by project (utilization; multiplier; research credit). Payroll; licensure and CE; dues (political excluded); education assistance. Sub-consultant W-9s, certificates, 1099s. Software by seat; hardware (de minimis / 179). Professional liability by project type; tail planning; cyber. Studio rent and build-out (QIP); model shop equipment. Marketing: proposals (hours), photography, awards, competitions. 179D file: allocation letters, certifications, construction start vs the June 30, 2026 cutoff. Contract method (cash / accrual / POC). Sales tax on reimbursables and SaaS. The 179D file is the line that separates design firms that claim it from those that never asked.

Worked example

A fourteen-person architecture firm grosses US$3.6 million: US$2.8 million of design fees, US$620,000 of sub-consultant fees passed through (structural, MEP, civil, landscape — five firms with W-9s, certificates, and 1099s to the two that aren't incorporated; the firm's 10 percent markup on separate revenue and cost lines), and US$180,000 of reimbursables (revenue and expense — printing, travel, renderings, permit fees advanced). People: eleven design staff and three administrative on payroll (US$1.7 million) — four licensed architects, two staff sitting for exams (the firm pays the exam fees — through its section 127 plan where its adviser is comfortable, otherwise as wages), the state's CE hours, and the professional society dues less the designated political portion; utilization at 62 percent and a net multiplier of 3.1 from the timekeeping. Software: US$96,000 of per-seat subscriptions (BIM, rendering, energy modeling, project management, specifications, billing) expensed; six new BIM workstations (US$34,000, section 179), a laser cutter for the model shop (section 179, or de minimis if it cost US$2,500 or less). Professional liability rated for the firm's K-12 school and multifamily work (US$74,000), cyber, GL. The studio's build-out two years ago on the schedule as QIP. Marketing: US$140,000 of unbilled RFP hours (in overhead, not project costs), portfolio photography, two awards submissions. The 179D allocation: two public school projects completed this year — the district's allocation letters obtained, a licensed engineer's certification of the lighting and HVAC systems' efficiency, and a US$410,000 deduction allocated to the firm as designer (both projects' construction began well before the June 30, 2026 cutoff); a third school with construction starting next year falls after it — no 179D deduction to allocate. Cash method (under the threshold), fees recognized as paid by phase. Net profit to the two principals lands in the high six figures — an S corporation with salaries from the employed-principal market (the entity guide), and the QBI deduction in full because architecture is excluded from the specified-service list — a deduction the firm's attorney and its accountant, at the same income, both lost. The firm across the river, with the same public school work, never asked the district for an allocation letter — US$400,000 of deduction left with an owner who couldn't use it.

Official sources

The IRS states: “The deduction was previously available only to owners of qualified commercial buildings and designers of EECBP installed in buildings owned by certain government entities.” — Internal Revenue Service, Energy Efficient Commercial Buildings Deduction, https://www.irs.gov/credits-deductions/energy-efficient-commercial-buildings-deduction

The IRS states: “The QBI Component is subject to limitations, depending on the taxpayer's taxable income which may include the type of trade or business, the amount of W-2 wages paid by the qualified trade or business, and the unadjusted basis immediately after acquisition (UBIA) of qualified property held by the trade or business.” — Internal Revenue Service, Qualified business income deduction, https://www.irs.gov/newsroom/qualified-business-income-deduction

Practitioner note

A design firm's return is people, software, and a professional liability policy priced for the buildings it drew — with two features that separate the profession from its neighbors: architects and engineers are expressly excluded from the specified-service list, so the QBI deduction survives at every income, and the designers of energy-efficient public buildings can be allocated a section 179D deduction the tax-exempt owner can't use. Our design firm files keep sub-consultants and reimbursables on separate lines, put the RFP hours in overhead rather than the project, and request the allocation letter from every public owner before the project closes — because the firm across the river left US$400,000 with a school district that couldn't spend it, and the June 30, 2026 construction-start cutoff has now passed.

See also: For related guidance, see how the qualified business income deduction works; and browse every small business tax guide, by situation.

Next step

Fairlight Accounting is a cross-border accounting and tax practice with a U.S. Tax Desk and a Canadian Tax Desk. Our U.S. Tax Desk handles architecture and engineering firm returns and bookkeeping — project revenue with sub-consultant and reimbursable pass-throughs, timekeeping-based diagnostics, licensure and education assistance treatment, software and hardware elections, professional liability structuring, 179D allocation files and termination-date analysis, research credit documentation, and QBI computation under the design exclusion. See pricing or book a call.