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BUILDER (BU)

The Seabee carpenter, mason, and structural builder — buildings, bridges, and concrete from a Naval Construction Battalion.

Rating Badge

Rating Code

Community

Seabees (NCF)

Paygrade Range

E-1 to E-9

ASVAB Minimum

AR+MK+EI+GS=140

A-School

Naval Construction Training Center, Gulfport, MS · ~10 weeks

Clearance

Standard

Obligation

4 years

OVERVIEW

Builder (BU) is the carpentry, masonry, and concrete-construction rating in the U.S. Navy's Naval Construction Force — the Seabees. BUs frame buildings, place concrete, set forms, lay block and brick, install drywall and roofing, and build the wooden and steel-stud structures of every Seabee project, from contingency airfields to schools in disaster-relief zones.

The BU rating is one of seven Seabee ratings — BU, CE, CM, EA, EO, SW, UT — that together comprise the Naval Construction Force. Seabees serve in Naval Mobile Construction Battalions (NMCBs) at NCBC Gulfport, MS and NCBC Port Hueneme, CA.

The Seabees — the Naval Construction Force (NCF) — are the U.S. Navy's expeditionary engineers, building airfields, camps, bridges, roads, and piers in austere locations worldwide. Seabees deploy with Naval Mobile Construction Battalions (NMCBs), Underwater Construction Teams (UCTs), and Naval Construction Regiments. Their motto, "Construimus, Batuimus" — "We build, we fight" — captures their dual role.

A-school for the rating runs ~10 weeks at Naval Construction Training Center, Gulfport, MS, where Sailors complete the technical foundation needed to report to their first fleet command. Entry requires the ASVAB line score AR+MK+EI+GS=140 and an enlistment obligation of 4–6 years. BUs advance through the standard enlisted paygrade structure (E-1 through E-9), competing in the Navy-Wide Advancement Examination (NWAE) at E-4 through E-6 and via the Selection Board at E-7 through E-9. Senior BUs typically serve as Leading Petty Officer (LPO), Work Center Supervisor, Leading Chief Petty Officer (LCPO), or Command Master Chief (CMC), and may pursue Limited Duty Officer (LDO), Chief Warrant Officer (CWO), or commissioning programs such as STA-21, MECP, or OCS.

Across the active force, BU Sailors are essential to the Navy's mission readiness, and the rating remains an in-demand career field with strong reenlistment bonuses (SRB), advancement opportunities, and pathways into Navy Reserve, civilian DoD, and industry careers after service.

WHAT BUs DO

Builders frame stick and steel-stud structures, place reinforced concrete (slab, wall, footing), set forms and rebar, lay concrete masonry units (CMU) and brick, install roofing systems (built-up, metal, shingle), install drywall and insulation, and perform finish carpentry. On contingency projects, BUs build expeditionary structures (SEA huts, K-spans, Alaska barrels), tactical airfields, and force-protection berms. BUs also serve as the construction-trade leads on humanitarian-assistance and disaster-relief missions.

RESPONSIBILITIES

Builders frame stick and steel-stud structures, place reinforced concrete (slab, wall, footing), set forms and rebar, lay concrete masonry units (CMU) and brick, install roofing systems (built-up, metal, shingle), install drywall and insulation, and perform finish carpentry. On contingency projects, BUs build expeditionary structures (SEA huts, K-spans, Alaska barrels), tactical airfields, and force-protection berms. BUs also serve as the construction-trade leads on humanitarian-assistance and disaster-relief missions.
Stand watches and qualify on the rating's Personnel Qualification Standards (PQS), maintain training jackets, and mentor junior BUs as required by the chain of command.
Lead the BU work center as Leading Petty Officer or Work Center Supervisor — managing maintenance documentation in 3M/MFOM, parts ordering, and personnel qualifications.
Support general military training (GMT), damage control, force protection, and watch-bill assignments common to every Sailor regardless of rating.

HISTORY

The Builder rating dates to the establishment of the Seabees in March 1942, when the U.S. Navy recruited civilian construction tradesmen to build airfields and bases across the Pacific in support of the WWII island-hopping campaign. The original Seabee ratings were CB1c through CB7c specialty rates, which were consolidated into the modern construction ratings (BU, CE, CM, EA, EO, SW, UT) in the post-war reorganization.

The Seabee motto — "Construimus, Batuimus" ("We Build, We Fight") — has marked the Naval Construction Force ever since.

The Naval Construction Force was established on 5 March 1942 by RADM Ben Moreell of the Civil Engineer Corps to provide militarized construction units for World War II — replacing civilian contractors who, under the laws of war, could not resist enemy attack. The Seabees built bases, airstrips, and pontoon causeways across the Pacific and Europe and have deployed in every conflict since.

Today the Builder (BU) rating is overseen by the Enlisted Community Management (ECM) office at My Navy HR and the Center for Personal and Professional Development. Modern BUs benefit from the Sailor 2025 personnel-system reforms, the Ready Relevant Learning (RRL) training continuum, and credentialing through the Navy COOL program — turning rating qualifications into industry-recognized certifications and licenses.

The rating's structure, training pipeline, and operational employment continue to evolve alongside the Navy's transition to Distributed Maritime Operations (DMO), Project Overmatch, and the Force Design 2045 fleet architecture, ensuring BUs remain central to the warfighting mission.

TRAINING PIPELINE

1. Recruit Training (Boot Camp)~10 weeks
Naval Station Great Lakes, IL
Initial entry training for all U.S. Navy enlisted Sailors at the Navy's only boot camp.
2. Builder A-School~10 weeks
Naval Construction Training Center, Gulfport, MS
Initial rating-skills training for BU accessions.
3. Fleet / Operational TourFirst sea or operational tour
Naval Mobile Construction Battalions (NMCBs)
On-the-job training and qualifications in the BU rating with a fleet unit.

TYPICAL CAREER PATH

E-1/E-3
Apprentice Builder
A-school at Gulfport; first tour with an NMCB construction company.
E-4/E-6
Petty Officer Builder
Qualify as crew leader on framing, concrete, masonry, and roofing crews; lead a project alpha-bravo team.
E-7+
Chief Builder
Construction Company Chief, NMCB Operations Department LCPO, or instructor at NCTC Gulfport.

TYPICAL PLATFORMS & UNITS

Naval Mobile Construction Battalions (NMCBs)
Underwater Construction Teams
Naval Construction Group staffs
Expeditionary contingency construction worldwide

EXAMPLE NECs

BU-5751 Concrete Forms and Placement Supervisor

How to address

As an enlisted Sailor by paygrade and last name (e.g. "Petty Officer Smith" for E-4–E-6, "Chief Smith" for E-7+). The rating abbreviation "BU" is appended to the paygrade in writing — e.g., BU1 Smith for BU Petty Officer First Class.

Prerequisites

U.S. citizenship and minimum ASVAB AR+MK+EI+GS=140
High school diploma or equivalent
Pass the Navy physical and medical screening

Common assignments

Naval Mobile Construction Battalions (NMCBs)
Underwater Construction Teams
Naval Construction Group staffs
Expeditionary contingency construction worldwide

RELATED RATINGS

RELATED BASES

Navy Base · CA
Naval Base Ventura County

FREQUENTLY ASKED QUESTIONS

BUs frame buildings, place concrete, lay masonry, install roofing and drywall, and build the wooden and steel-stud structures of every Seabee project — from forward-operating-base buildings to disaster-relief schools.

Builder A-school is at the Naval Construction Training Center, Naval Construction Battalion Center Gulfport, MS — the East Coast Seabee homeport.

"Seabee" is the phonetic pronunciation of "C.B." — Construction Battalion. The U.S. Navy's Naval Construction Force was founded in March 1942 with the motto Construimus, Batuimus — We Build, We Fight.

SOURCES

Last updated 2026-05-02

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