Floor/Ceiling Assemblies, Walls, + stairs
LESSON 5 | CHAP 5
BUILDING SYSTEMS FOR INTERIOR DESIGNERS
Structural floor systems
Floor finishes + performance
Ceiling systems
Design coordination
Floor and Ceiling Assemblies
Why Floors and Ceilings Matter in Interior Design
Floors and ceilings influence:
• Structural support
• Acoustics
• Fire protection
• Mechanical distribution
• Lighting integration
A floor assembly typically includes: • Structural floor system • Subfloor • Floor finish • Insulation or acoustic layer
Floor Assemblies
The assembly must support loads and provide comfort.
Common structural floor systems include:
• Wood joist systems
• Steel framing systems
• Concrete slab systems
Structural Floor Systems
Each system affects ceiling height and mechanical routing.
Wood Joist Floors
Common in residential construction.
Components:
• Wood joists
• Subfloor sheathing
• Finish flooring
Advantages:
• Economical
• Easy to modify
Limitations:
• Shorter spans
• Less fire resistance
Steel Floor Systems
Common in commercial buildings.
Components:
• Steel beams
• Steel decking
• Concrete topping slab
Advantages:
• Long spans
• Strong and durable
• Flexible interior layouts
Used in many mid-rise and high-rise buildings.
Types include:
• Reinforced concrete slabs
• Precast concrete systems
• Post-tensioned slabs
Advantages:
• Fire resistance
• Strength
• Sound control
Concrete Floor Systems
Floor finishes affect: • Durability • Acoustics • Maintenance • Comfort Examples: • Tile • Wood • Carpet • Stone • Vinyl
Floor Finishes
Interior designers select finishes based on use and performance.
Floor Performance Considerations
Important performance factors
Maintenance requirements
Moisture resistance
Acoustics
Slip resistance
Load capacity
Ceilings serve several purposes:
• Conceal building systems
• Improve acoustics
• Support lighting fixtures
• Provide fire protection
Ceiling Systems
They are also important design elements.
Common ceiling systems include: • Exposed structural ceilings • Suspended (drop) ceilings • Gypsum board ceilings
Types of Ceilings
Each type offers different design possibilities.
Suspended Ceiling Systems
Ceiling tiles or panels
Suspension wires
Grid system
Benefits:
• Easy access to HVAC and electrical systems
• Acoustic control
• Flexible layout
Integrated Building Systems
Ceilings often house: • HVAC ducts • Lighting systems • Fire sprinklers • Electrical wiring • Data systems
Coordination between disciplines is essential.
Ceiling materials influence sound control. Acoustic ceilings can: • Absorb sound • Reduce noise • Improve speech clarity
Acoustics + Ceiling Design
Important in offices, classrooms, and healthcare spaces.
STAIRS
Stairs must meet building codes and ADA standards. Exit stairs have extra fire safety rules. Codes also specify safe design features for supporting weight and movement.
STAIRS
Most stairs must have a clear minimum width of 44 in. The IRC requires a residential stair to have a minimum width of 36 in. More than just risers and treads, handrails, landings, and headroom must be considered in their design.
Conclusions
Floors support structural loads and provide usable surfaces.
Floor assemblies include structure, subfloor, and finish materials.
Ceiling systems conceal building systems + affect acoustics.
Conclusions
Designers must coordinate structural, mechanical, and aesthetic elements.
Floor and ceiling design strongly influences interior performance.
Designing of stairs is strictly regulated by Codes +ADA
Located in Beijing China, The QiHu Hotel is a palette of luxury earthy textures that frame an outstanding view of the Yanqi Lake. Harmany and balance is within each space, material selection, and space planning of this hotel by WATG
Floor/Ceiling Assemblies
Maryse Jospitre
Created on February 26, 2026
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Transcript
Floor/Ceiling Assemblies, Walls, + stairs
LESSON 5 | CHAP 5
BUILDING SYSTEMS FOR INTERIOR DESIGNERS
Structural floor systems
Floor finishes + performance
Ceiling systems
Design coordination
Floor and Ceiling Assemblies
Why Floors and Ceilings Matter in Interior Design
Floors and ceilings influence: • Structural support • Acoustics • Fire protection • Mechanical distribution • Lighting integration
A floor assembly typically includes: • Structural floor system • Subfloor • Floor finish • Insulation or acoustic layer
Floor Assemblies
The assembly must support loads and provide comfort.
Common structural floor systems include:
• Wood joist systems • Steel framing systems • Concrete slab systems
Structural Floor Systems
Each system affects ceiling height and mechanical routing.
Wood Joist Floors
Common in residential construction. Components: • Wood joists • Subfloor sheathing • Finish flooring Advantages: • Economical • Easy to modify Limitations: • Shorter spans • Less fire resistance
Steel Floor Systems
Common in commercial buildings. Components: • Steel beams • Steel decking • Concrete topping slab Advantages: • Long spans • Strong and durable • Flexible interior layouts
Used in many mid-rise and high-rise buildings.
Types include: • Reinforced concrete slabs • Precast concrete systems • Post-tensioned slabs Advantages: • Fire resistance • Strength • Sound control
Concrete Floor Systems
Floor finishes affect: • Durability • Acoustics • Maintenance • Comfort Examples: • Tile • Wood • Carpet • Stone • Vinyl
Floor Finishes
Interior designers select finishes based on use and performance.
Floor Performance Considerations
Important performance factors
Maintenance requirements
Moisture resistance
Acoustics
Slip resistance
Load capacity
Ceilings serve several purposes:
• Conceal building systems • Improve acoustics • Support lighting fixtures • Provide fire protection
Ceiling Systems
They are also important design elements.
Common ceiling systems include: • Exposed structural ceilings • Suspended (drop) ceilings • Gypsum board ceilings
Types of Ceilings
Each type offers different design possibilities.
Suspended Ceiling Systems
Ceiling tiles or panels
Suspension wires
Grid system
Benefits: • Easy access to HVAC and electrical systems • Acoustic control • Flexible layout
Integrated Building Systems
Ceilings often house: • HVAC ducts • Lighting systems • Fire sprinklers • Electrical wiring • Data systems
Coordination between disciplines is essential.
Ceiling materials influence sound control. Acoustic ceilings can: • Absorb sound • Reduce noise • Improve speech clarity
Acoustics + Ceiling Design
Important in offices, classrooms, and healthcare spaces.
STAIRS
Stairs must meet building codes and ADA standards. Exit stairs have extra fire safety rules. Codes also specify safe design features for supporting weight and movement.
STAIRS
Most stairs must have a clear minimum width of 44 in. The IRC requires a residential stair to have a minimum width of 36 in. More than just risers and treads, handrails, landings, and headroom must be considered in their design.
Conclusions
Floors support structural loads and provide usable surfaces.
Floor assemblies include structure, subfloor, and finish materials.
Ceiling systems conceal building systems + affect acoustics.
Conclusions
Designers must coordinate structural, mechanical, and aesthetic elements.
Floor and ceiling design strongly influences interior performance.
Designing of stairs is strictly regulated by Codes +ADA
Located in Beijing China, The QiHu Hotel is a palette of luxury earthy textures that frame an outstanding view of the Yanqi Lake. Harmany and balance is within each space, material selection, and space planning of this hotel by WATG