How to Read Wall Type Schedules

The Quick Answer

Wall type schedules appear on the architectural A-series (typically A-0.01 or A-6.xx). Each wall type has a tag (A1, B2, etc.) that matches a graphical/textual detail. The detail shows a cross-section through the wall with all layers labeled from outside (or "Side A") to inside (or "Side B"). Fire ratings, acoustic ratings, and UL assembly numbers appear in the detail header.

Anatomy of a Wall Type Detail

A complete wall type detail includes:

• Tag and title: A1, B2, or a descriptive name ("1-hour interior partition")
• Fire rating: 0, 1, 2, 3, or 4-hour, with UL assembly number (e.g., UL U419)
• STC rating: Acoustic Sound Transmission Class (STC 35–65 typical)
• Stud type and gauge: 3-5/8" 25ga, 3-5/8" 20ga, 6" 18ga, etc.
• Stud spacing: 16" or 24" o.c.
• Sheathing: 5/8" Type X gypsum board, glass mat exterior, etc.
• Insulation: R-value, type (batt, rigid, spray foam), thickness
• Extent: Slab-to-deck, slab-to-slab, slab-to-finished ceiling
• Head and base conditions: Deflection track at head, coved base at floor
• Notes: Penetration requirements, additional testing, and special conditions

UL Assembly Numbers

UL assembly numbers encode the assembly type. The first letter indicates the wall type:

• U: Non-load-bearing wood or steel stud wall
• V: Load-bearing wood stud wall
• W: Load-bearing steel stud wall
• P: Plywood or OSB sheathed wall
• BXUV: Wall or partition master directory

The number that follows is the specific tested assembly. Every detail, substitution, and modification must match a listed UL number or it doesn't carry the tested rating. Related: MEP penetration details.

STC and Acoustic Performance

STC ratings indicate airborne sound transmission. Common targets:

• STC 35: Minimum for office-to-office or tenant demising walls (speech privacy)
• STC 45–50: Typical hotel or dormitory room-to-room
• STC 50: IBC minimum for dwelling unit demising walls
• STC 55–60: Hospital patient rooms, multifamily demising in high-quality projects
• STC 65+: Broadcast studios, music rooms, conference rooms with video

STC ratings degrade at penetrations, so the wall type must coordinate with acoustic-listed door and glazing assemblies.

Wall Extent Callouts

Wall type schedules often tag the extent:

• Slab-to-Deck: Full-height, required for fire-rated smoke-stopping
• Slab-to-Slab: Structural floor-to-floor for acoustic walls in multifamily
• Slab-to-6" Above Ceiling: Non-rated partition terminated above accessible ceiling
• Furred-Out: Partition over existing wall, usually for MEP routing

Extent determines where firestopping applies, whether the wall forms a smoke barrier, and how it interacts with the ceiling assembly. See ceiling grid coordination for the ceiling side.

Common Review Errors

• Wall type on plan doesn't match the schedule (tag mismatch)
• UL assembly number missing from fire-rated walls
• Demising wall in residential lacks STC-50 rating
• Wall extent not labeled—contractor guesses slab-to-deck vs. slab-to-ceiling
• Stud gauge too light for wall height (check stud manufacturer height tables)
• Wall type changes between floors not reflected in the schedule