Other Foundation, Structure, and Building Exterior Contractors (NAICS 23819)

A Histometrics industry primer for public-market and private investors

Read this as a signpost, not a full report. NAICS (North American Industry Classification System) code 23819 is a five-digit industry that contains exactly one six-digit child, 238190, of the same name. At this level the two are effectively identical, so this page is deliberately short: it states this level's own ground-truth federal figures and then points you to the full 238190 primer for the detail. For scope, the investable universe, deal economics, demand drivers, regulation, consolidation, and risks, read primer 238190.

1. Overview

NAICS 23819 is the "everything else" bucket of the specialty trades that put up a building's skeleton and skin — the crews installing metal curtain walls and storefronts, architectural sheet metal, ornamental and wrought-iron work, metal stairs and balconies, awnings and shutters, temporary concrete forms and falsework, fire escapes, on-site welding, and waterproofing.[1] Most of the work is subcontracted from general contractors; a slice of repair and remodeling is sold directly to property owners.[1]

For an investor this is picks-and-shovels exposure to the building cycle — offices, warehouses, data centers, schools, hospitals, stadiums — plus a slice of high-end residential. Returns depend far more on labor productivity, safety, contract discipline, backlog quality, and cash conversion than on physical capacity. The catch is access: this is one of the most fragmented corners of the U.S. economy, with no meaningful publicly traded pure-play, so public-market investors reach it only indirectly. All of that is developed in full in the 238190 primer.[1]

2. What's inside — and why this level equals its one child

In the NAICS hierarchy, five-digit industries can hold several six-digit national industries. Here there is only one:

Because the U.S. and its NAICS partners never split this residual "Other" category into finer national industries, 23819 and 238190 describe the same set of establishments. The five-digit code exists only to preserve a consistent hierarchy; it carries no additional scope, no separate definition, and no separate statistics beyond those of its single child. Everything true of 238190 — the metal-façade, ornamental-metal, forming, waterproofing, and on-site-welding work; the carve-outs to the larger sibling trades (poured concrete 238110, structural steel 238120, framing 238130, masonry 238140, glass/glazing 238150, roofing 238160, siding 238170); and the establishment-not-company classification rule — is true of 23819 without change.[1]

3. Size (this level's rollup figures)

Because there is one child, this level's rollup is the child's figure — the numbers do not sum across multiple children; they simply carry through. These are our ground-truth federal stats for 23819:[2][3]

That works out to roughly $70,000 of payroll per employee (2023) and about $1.85 million of revenue per firm (2022)[2][3] — a small-shop industry. The two headline series come from different surveys and years (receipts from the 2022 Economic Census, employment and payroll from 2023 County Business Patterns), so read them as a size profile, not a single-period income statement. Our federal file for this level carries no industry-wide profit, margin, backlog, utilization, or capital-expenditure series, so those are simply not reported here.

Undercount caveat (matters here). These figures capture only businesses with employees. County Business Patterns excludes the self-employed, one-person outfits, and most government workers, and much foundation/exterior specialty work is done by exactly such nonemployers. No 23819 nonemployer count or receipts figure was supplied, so we state none. Separately, because this is a residual "Other" code, a great deal of real-world building-exterior activity is booked into the larger sibling trades. Treat the ~$10.6 billion receipts figure as a floor on the economic footprint, not the whole of it.

4. Investable universe (where value concentrates)

With a single child, there is nowhere else for value to "concentrate" across children — the entire investable picture is the 238190 picture. The federal concentration data show why this is a private-market story: the four largest firms account for just 8.3% of revenue, the top eight 11.6%, the top twenty 17.8%, and the top fifty only 26.9%; the Herfindahl-Hirschman Index (HHI, a 0–10,000 concentration gauge) is about 27 — near the theoretical floor for a fragmented market.[3]

There is no publicly traded pure-play. Public-market investors approximate the space through diversified specialty contractors and upstream building-products makers, and the real exposure lives in thousands of private, often family- or employee-owned firms. The named proxies and private leaders — and the basis risk of using them — are laid out in section 4 of the 238190 primer.[1]

5. How the money works

The economics are those of project-based subcontracting, not manufacturing or retail: signed backlog (measured in months of revenue) is the leading indicator; margins are thin and made or lost on crew productivity and rework; materials (steel, aluminum, glass, coatings) are largely a per-job pass-through until a fixed-price contract without escalation turns a metals spike into a direct margin hit; skilled labor is the binding constraint; and cash flow beats accounting profit because contractors front labor and materials, wait to get paid, and have 5–10% retainage held back until completion. Surety bonding capacity effectively caps how large a project a firm can chase. In a private roll-up, value comes from pooling bonding capacity, cross-selling trades, professionalizing estimating, and buying small firms at ~4–6x EBITDA (earnings before interest, taxes, depreciation, and amortization). The full treatment is in section 5 of the 238190 primer.[1]

6. Demand drivers

Demand tracks total construction put in place — private nonresidential (offices, warehouses, institutional buildings, and the standout data-center segment), private residential, and public work — read through leading indicators like the American Institute of Architects' (AIA) Architecture Billings Index (ABI) and contractor backlog. Interest rates gate debt-financed starts; renovation, re-cladding, and code-driven façade remediation supply steadier, less-cyclical repair demand. See section 6 of the 238190 primer for the detail.[1]

7. Regulation

Licensing, insurance, and surety bonding are state- and trade-specific; worker-safety rules (the Occupational Safety and Health Administration's fall-protection and steel-erection standards) bear heavily on at-height façade and structural work; the Davis-Bacon and Related Acts set prevailing wages on covered public projects; and the U.S. Small Business Administration's (SBA) size standard for this code is $19.0 million in average annual receipts.[1] Full detail is in section 7 of the 238190 primer.

8. Consolidation

The defining feature is fragmentation — thousands of small firms, no dominant player — which makes the space a magnet for private-equity (PE) roll-ups and employee-stock-ownership-plan (ESOP) conversions. Subcontractor-segment M&A jumped roughly 39% in 2025, and even marquee private players grow by acquisition; roll-ups carry real integration risk (estimating systems, union relationships, local licenses, and safety cultures do not combine as cleanly as financial statements). See section 8 of the 238190 primer.[1]

9. Risks

The main risks are the child's risks, unchanged: cyclicality against the nonresidential building cycle; fixed-price / input-cost exposure; labor scarcity and wage inflation; project and execution risk (overruns, rework, disputed change orders); working-capital and bonding strain; customer concentration; safety and liability; public-proxy basis risk (a listed name may have little real exposure); and private-company opacity. Each is developed in section 9 of the 238190 primer.[1]

10. How to invest and outlook

Because 23819 equals 238190, the routes are identical. Public-market: all indirect — the closest listed exposure is a curtain-wall/architectural-services business packaged with glass fabrication, alongside building-products suppliers and diversified specialty contractors; there is no ETF (exchange-traded fund) or pure-play for the niche. Private: direct buyout of a regional metal, façade, waterproofing, or forming contractor; PE roll-up platforms; and ESOP or owner-financed successions, underwritten on project-level evidence (work-in-progress schedules, gross-profit fade, change-order history, customer concentration, safety, bonding). The near-term outlook is cautiously constructive but uneven — flat-ish overall nonresidential spending offset by double-digit data-center and AI-infrastructure growth, with the durable long-run thesis being consolidation of a fragmented, aging-workforce industry. For the complete how-to-invest playbook and outlook, read section 10 of the 238190 primer.[1]

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Sources

1. Histometrics. "Other Foundation, Structure, and Building Exterior Contractors (NAICS 238190)" — child-industry primer (full scope, investable universe, economics, demand, regulation, consolidation, risks, and outlook, with its own numbered sources). See primer-238190-DRAFT.md.
2. U.S. Census Bureau. "County Business Patterns, 2023 — NAICS 238190 / 23819" (establishments, employment, annual and Q1 payroll). https://www.census.gov/data/datasets/2023/econ/cbp/2023-cbp.html
3. U.S. Census Bureau. "2022 Economic Census — Concentration and receipts, NAICS 238190 / 23819" (firms, receipts, CR4/CR8/CR20/CR50, HHI). https://data.census.gov/table/ECNSIZE2022.EC2200SIZECONCEN?codeset=naics~238190