Interior Finishes: Part Two Finish Ceilings and Floors
Finish Ceilings • Broadly characterized as one of the following: • Exposed Structure • “Tightly Attached” Ceilings • Suspended Ceilings
Finish Ceilings • Exposed Structure: • May be used where an inherently attractive structural system has been designed and detailed with the expressed intent to remain exposed. • May also be used for economy: industrial uses, or when a provision for ceiling run mechanical or electrical is unnecessary, (typically in conjunction with a plenum supply and return system)
Finish Ceilings • Tightly attached ceilings: • Essentially any material attached to, rather than suspended from, the structure above. • Provisions must be made for services: HVAC, plumbing and fire suppression • Changes in plane: where structural elements protrude through the ceiling plane, for example, need to be carefully detailed, (bulkheads).
Finish Ceilings • Suspended Ceilings • A ceiling that is suspended below the structural framework of the floor above, providing a level “datum” for a ceiling and providing a space through which a multitude of services may be run. • By far the most common in commercial applications • Membrane fire protection: provides a 1-hour minimum fire and Class B flame spread rating.
Specifying Gypsum Board • The same specifications for wall applied board apply to ceiling applied board: • Level 0: attached boards only, no tape • Level 1: joints covered in tape set in joint compound • Level 2: a finish coat of compound over the tape and accessories, (garages, warehouses) • Level 3: a second coat of compound, (prior to textured coating) • Level 4: a third coat, (flat paints, light wallcoverings) • Level 5: skim coat
Suspended Ceilings • Suspended “Plaster” Ceilings • A rigid surface, typically gypsum board, mounted to an independent structural subsystem, (page 844). • Typically a flat application, although more sculpted shapes may also be produced, from a modest tray configuration to a highly articulated surface, typical of spaces where acoustical control is of concern.
Suspended Ceilings • Acoustical Ceilings • Typically constructed of fibrous materials in the form of lightweight tiles or panels in a standardized size fit into a suspended grid. • Referred to as “acoustical” because in contrast to rigid ceiling products, they are absorptive of sound.
Acoustical Ceilings • The sound absorptive qualities of a ceiling finish material is measured by the Noise Reduction Coefficient, (NRC): • An NRC of 85 indicates that 85 percent of the sound that reaches the product is absorbed, while only 15 percent is reflected back into the space. • However, this also indicates a direct correlation to the amount of sound that is passed through the product to the space beyond.
Acoustical Ceilings and Plenums • Plenum: an open, unobstructed space between the ceiling and the structural deck above, typically the structure of the floor above, although in some precast concrete structures the plenum may be part of the structure itself. • When the plenum is continuous between multiple rooms, sound transmittal may be an issue.
Acoustical Ceilings and Plenums • Ceiling Attenuation Class, CAC: • The ability of a ceiling construction to reduce room to room sound transfer through the plenum • Composite ceiling panels, panels constructed from a highly absorbent material facing the acoustical space with a denser material mounted to the back or plenum have simultaneously high CAC and NRC values.
Acoustical Ceilings • “Lay-In” Ceilings • Suspended on a ceiling grid: 2 feet by 2 feet or 2 feet by 4 feet. • Grid may be any one of a series of profiles: “T” is most common • Panels in a variety of finishes and price points • Linear Metal Ceilings • Provide an acoustical and structural surface
Interstitial Ceilings • Interstitial: space between • Interstitial ceilings are inhabitable service spaces between occupied floors • Hospitals and laboratory buildings: multiple conduits and services that require consistent service and maintenance • Retail: security and surveillance
Finish Floors • Primary wearing surface • Appearance • Skid resistance • Wear resistance • Resilience • “Underfloor” services
Underfloor Services • Provide a structure to allow for the distribution of services: especially wiring for electrical and technology • Cellular steel decking: used with steel framing • Cellular raceways: used with a topping slab in concrete construction • Raised access flooring: provides an easily accessed space with essentially unlimited space for wiring, piping and ductwork. (Computer labs and server-type spaces)
Noise Transmission • STC: sound transmission coefficient • Measure of airborne noise • Transmitted as a membrane vibration • ITC: impact transmission class • Measure of impact noise • Impact noise is transmitted as a vibration through structure.
Noise Transmission through Floors • Strategies: • Soft surfaces, such as carpeting, reduce the amount of impact noise transferred • Placing a soft or resilient surface, such as a cork or fibrous underlayment beneath a hard surface will reduce the amount of noise transmitted. • Ceiling mounts isolated from the structure: resilient clips or spring-mounted hanger wires.
Skid Resistance • Static Coefficient of Friction: SCOF • Measure of the “slipperiness” of a flooring • Commercial applications typically require an SCOF of 0.5 or above • Particular care must be taken where surfaces may be exposed to water
Flooring • Hard surfaces • Concrete • Stone • Pavers • Tile • Terrazzo • Wood Flooring • Resilient Flooring • Soft Surfaces • Carpet
Floating Floors • Surface is not directly attached to the subfloor but instead “floats” above on a cushion of resilient foam. • Hardwood veneers, typically applied to an engineered wood substrate • Cork, also typically applied to an engineered wood substrate • Plastic laminates • Epoxy Terrazzo
Resilient Floors • Resilient flooring is any one of a variety of floor surfaces that resist wear and gouging or puncturing. They may be natural, cork or made from natural products, linoleum or man-made, vinyl composite. • Although durable, resilient floorings tend to be flexible and tend to “telescope” or transmit any irregularities in the subfloor to the surface.
Resilient Floor Types • Linoleum: lino, flax – linseed oil • Ground cork in a linseed oil binder over a burlap backing, (hemp). Produced as tiles or sheet flooring. • Rubber • Tiles or sheet flooring. • Pirelli flooring: raised dot grid • Vinyl Composition Tile, VCT • Polyvinyl chloride with mineral reinforcing fibers