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 suppressionChanges in plane: where structural elements

protrude through the ceiling plane, for example, need to be carefully detailed, (bulkheads).

Finish Ceilings

Suspended CeilingsA 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 tapeLevel 1: joints covered in tape set in joint compoundLevel 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” CeilingsA 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 CeilingsTypically 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” CeilingsSuspended 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 commonPanels in a variety of finishes and price points

Linear Metal CeilingsProvide an acoustical and structural surface

Interstitial Ceilings

Interstitial: space between

Interstitial ceilings are inhabitable service spaces between occupied floorsHospitals and laboratory buildings: multiple

conduits and services that require consistent service and maintenance

Retail: security and surveillance

Finish Floors

Primary wearing surfaceAppearanceSkid resistanceWear resistanceResilience“Underfloor” services

Underfloor Services

Provide a structure to allow for the distribution of services: especially wiring for electrical and technologyCellular steel decking: used with steel framingCellular raceways: used with a topping slab in

concrete constructionRaised 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 coefficientMeasure of airborne noiseTransmitted as a membrane vibration

ITC: impact transmission classMeasure of impact noiseImpact noise is transmitted as a vibration

through structure.

Noise Transmission through Floors

Strategies:Soft surfaces, such as carpeting, reduce the

amount of impact noise transferredPlacing 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: SCOFMeasure of the “slipperiness” of a flooringCommercial applications typically require an

SCOF of 0.5 or aboveParticular care must be taken where surfaces

may be exposed to water

Flooring

Hard surfacesConcreteStonePaversTileTerrazzoWood FlooringResilient Flooring

Soft SurfacesCarpet

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 substrateCork, also typically applied to an engineered

wood substratePlastic laminatesEpoxy 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 oilGround cork in a linseed oil binder over a

burlap backing, (hemp). Produced as tiles or sheet flooring.

RubberTiles or sheet flooring.Pirelli flooring: raised dot grid

Vinyl Composition Tile, VCTPolyvinyl chloride with mineral reinforcing

fibers