Class code 5645: residential carpentry and subcontractor exposure
This class is written for carpentry on detached one and two family dwellings specifically, and the biggest premium event in construction is not the rate but the uninsured subcontractor whose payroll is added to the contractor's base at audit.
| Manual description | Carpentry — Detached One or Two Family Dwellings |
|---|---|
| Hazard group | E |
| What it captures | Carpentry on detached one and two family dwellings, including framing, sheathing and interior trim on that specific building type. |
| Most common misclassification | Using it for carpentry on apartment blocks, townhouse rows or commercial buildings, which fall under different construction classes carrying different rates. |
| Payroll base | Gross wages. Uninsured subcontractors are typically added to the contractor's payroll base, so certificates of insurance are the cheapest audit defence in construction. |
| Source | NCCI Scopes of Basic Manual Classifications · Verified 2026-08-11 · Next review 2027-08-11 |
Construction classification is written by building type, not by trade alone. Carpentry on a detached house sits in this class; the same crew framing an apartment block or fitting out a commercial unit is classified elsewhere, at a different rate. Contractors who move between residential and light commercial work therefore carry more than one construction class in a single policy year, and the allocation is decided by job records. Keeping job costing that ties payroll to a specific address and building type is the difference between an allocation the auditor accepts and one the auditor assigns.
The dominant cost driver in this class is subcontractor documentation. Where a subcontractor cannot produce evidence of its own coverage for the period of the work, that subcontractor's payroll is generally added to the hiring contractor's premium base — and where records of the payroll are absent, a percentage of the contract value may be used instead. Collecting a certificate before the first day on site, with an expiry date diarised, is the cheapest risk control available to a residential contractor. Injury rates in construction remain well above the private-industry average in federal injury statistics, so the underwriting scrutiny is not arbitrary.
Contractors are the hardest population for a co-employer to place, and many arrangements decline high-hazard construction outright or write it with a separate carrier and a deposit. Before spending time on a quote, ask whether the provider writes this class at all, whether workers' compensation is bundled or placed separately, and how certificates for the general contractor are issued and renewed — a certificate that arrives late can stop a crew from reaching the site, which costs more than any fee difference.
What decides the rate, and what does not
No construction rate appears on this page. Residential carpentry loss costs are filed per state and then heavily reshaped by experience rating, which in construction reflects a small number of severe claims rather than a smooth average. Add the subcontractor question above and the payroll base itself becomes uncertain until certificates are collected, so the base — not the published rate — is where a contractor's premium is actually decided.
Where to go next
Run the numbers in the what this exposure costs against payroll, browse all published class codes, and start the category at the PEO overview. How we source and date every claim is set out in our methodology, the contractual duty split is explained at what a co-employer is contractually responsible for, and adjacent classifications include trucking, local hauling, code 7228, clerical office employees, code 8810, outside sales and collectors, code 8742.
What this doesn't cover
Construction classification is fact-heavy and this page cannot see your facts. Building type decides the class, job records decide the allocation, and certificates of insurance decide whether a subcontractor's payroll lands in your base — all of which are audited against documents rather than descriptions. Nothing here is a quote or a legal opinion on subcontractor status; confirm 5645 with your carrier for each project type.