UniFormat divisions are the seven Major Group Elements that organize a building by functional system under ASTM International standard E1557. Labeled A through G, they are Substructure, Shell, Interiors, Services, Equipment and Furnishings, Special Construction and Demolition, and Building Sitework. Each major group breaks down into Group Elements and then into Individual Elements, giving architects, engineers, and estimators a shared way to describe scope and costs before detailed drawings exist.
How The Codes Are Built
Before the list makes sense, the coding does. UniFormat nests from broad to specific, and the standard formally defines three levels with a fourth suggested in an appendix.
- Level 1 — Major Group Elements: A single letter, A through G. Seven in total, each a primary functional system of the building or site.
- Level 2 — Group Elements: A letter plus a two-digit number. B10 is Superstructure, B20 is Exterior Enclosure, B30 is Roofing, all sitting under the Shell category.
- Level 3 — Individual Elements: A four-character code. B2010 isolates Exterior Walls within the broader Exterior Enclosure group.
- Level 4 — Sub-Elements: A suggested extension in Appendix X1 of ASTM E1557 for finer breakdowns used in granular estimating and value engineering.
The tiered structure means the same data set can roll up to a one-line summary for an executive briefing or drill down to a sub-element for detailed budgeting.
The Seven Major Group Divisions
A — Substructure
Everything below the lowest floor that supports the building’s weight, including soil-contact elements and any below-grade enclosures.
- A10 Foundations: Spread footings, pile caps, grade beams, foundation walls, perimeter drainage, and slab-on-grade construction.
- A20 Basement Construction: Basement excavation, basement walls, and associated waterproofing.
B — Shell
The primary structural frame and the protective envelope that separates inside from outside. The two functions are grouped together because both define the building’s physical form.
- B10 Superstructure: Floor construction and roof construction, the structural framework that carries loads.
- B20 Exterior Enclosure: Exterior walls, windows, and doors forming the perimeter barrier.
- B30 Roofing: Roof coverings, insulation, and roof openings like skylights.
C — Interiors
The non-structural elements that define usable spaces within the shell. Keeping these separate from Group B is deliberate, since interior partitions and finishes change far more often than the structural frame, and isolating them simplifies renovation budgeting later on.
- C10 Interior Construction: Partitions (C1010), interior doors (C1020), and fittings (C1030) such as toilet partitions and built-in shelving.
- C20 Stairs: Stair construction and stair finishes.
- C30 Interior Finishes: Wall finishes, floor finishes, and ceiling finishes.
D — Services
The active mechanical, electrical, and plumbing systems that make a building functional. This is typically the most complex major group, with five Group Elements and numerous individual elements beneath them.
- D10 Conveying: Elevators and lifts, escalators and moving walks, and other conveying systems.
- D20 Plumbing: Fixtures, domestic water distribution, sanitary waste, and rainwater drainage.
- D30 HVAC: Energy supply, heating systems, cooling systems, distribution systems, terminal units, and controls.
- D40 Fire Protection: Sprinklers, standpipes, and fire protection specialties.
- D50 Electrical: Service and distribution, lighting and branch wiring, and communications and security systems.
Separating the physical structure in Group B from the active systems in Group D is one of UniFormat’s most practical features. It prevents the double-counting that happens when ductwork accidentally ends up in both a wall assembly and a mechanical line item.
E — Equipment and Furnishings
Items that serve the building’s specific programmatic function rather than its general operation.
- E10 Equipment: Commercial equipment, institutional equipment such as lab casework in a hospital or teaching stations in a school, and vehicular equipment.
- E20 Furnishings: Fixed furnishings like built-in cabinetry, and movable furnishings like desks and chairs.
F — Special Construction and Demolition
The catch-all for work that doesn’t fit the standard building categories, plus selective demolition for renovation projects.
- F10 Special Construction: Special structures, integrated construction systems such as clean rooms or integrated solar arrays, special facilities, and special controls.
- F20 Selective Building Demolition: Building elements demolition and hazardous components abatement.
G — Building Sitework
Everything outside the building footprint: grading, paving, landscaping, and the utility lines that connect the building to municipal infrastructure.
- G10 Site Preparation: Clearing, grading, and soil management.
- G20 Site Improvements: Roads, parking, walkways, landscaping, and site furnishings.
- G30 Site Mechanical Utilities: Water supply, sanitary sewer, storm drainage, and other below-grade piping beyond the building envelope.
- G40 Site Electrical Utilities: Exterior electrical distribution, site lighting, and communications infrastructure.
- G90 Other Site Construction: Service tunnels and miscellaneous site work.
The full A-through-G hierarchy is maintained jointly by the Construction Specifications Institute in the United States and Construction Specifications Canada.
Why UniFormat Groups Differ From MasterFormat Divisions
This confuses newcomers constantly, and getting it wrong leads to double-counting. UniFormat groups building components by what they do. An exterior wall assembly bundles studs, insulation, sheathing, and cladding under a single functional code (B2010). MasterFormat groups components by what they are, so that same wall splits across separate divisions for masonry, metal framing, and thermal insulation.
UniFormat answers “how much will the shell cost?” MasterFormat answers “how much drywall do we need to buy?” Project teams typically start with UniFormat during schematic design, when material choices haven’t been locked in, then transition to MasterFormat for procurement and bidding once construction documents exist. CSI maintains governed crosswalks between the two systems so a conceptual budget built in UniFormat can be translated into MasterFormat procurement packages as the design firms up.
Where The Divisions Actually Get Used
During schematic design, when the project team knows the building type and size but hasn’t selected specific products, the divisions let estimators apply composite elemental unit rates. A figure like “$19.25 per square foot for a brick-face composite exterior wall” captures material, labor, and subcontractor overhead in one number tied to a UniFormat element code. Major cost databases such as RSMeans structure their assembly-level data to align directly with UniFormat levels, so estimators start at Level 2 during schematic design and expand into Level 3 and Level 4 detail as the design develops.
The divisions also drive Building Information Modeling. The BIM Forum’s Level of Development Specification is organized around UniFormat, using element codes to define how detailed and reliable each component of a 3D model should be at each design stage. An architect can tag a model element as B2010 (Exterior Walls) at LOD 200 during schematic design and progressively add detail through construction, with the UniFormat code acting as the consistent identifier throughout. The COBie data exchange standard supports UniFormat as a classification scheme for asset handover, so a facility management team inherits the same organizational structure the design team used.
Federal Project Requirements
The General Services Administration’s P100 Facilities Standards establish mandatory design criteria for federally owned buildings, and GSA projects routinely require cost estimates organized by UniFormat elements. The Department of Energy’s facility management system references UniFormat Level 1 through Level 3 codes for asset classification. On government contracts, accurate UniFormat coding isn’t optional. Misclassifying an assembly can trigger contract disputes or result in rejected reimbursement claims during audits.
The discipline is straightforward but unforgiving. Each assembly must be identified precisely (a curtain wall is B2010, not a load-bearing masonry wall) before any cost code gets assigned. Those entries feed a master summary that auditors use to verify funds are allocated correctly across functional systems, and the resulting data set becomes a permanent part of the project record for decades of maintenance planning afterward.