F03C2 MATERIAL GUIDES - CORK FLOORING
F03C2-1 General Comments
F03C2-2 Cork underlayments for flooring
F03C2-3 Cork flooring preparation materials
F03C2-4 Adhesives
F03C2-5 Cork flooring
F03C2-2 Cork underlayments for flooring
F03C2-3 Cork flooring preparation materials
F03C2-4 Adhesives
F03C2-5 Cork flooring
Preface:
This study guide covers cork flooring and related materials. The information given is a guide only and cannot fully cover all aspects of such flooring and its installation. Specifiers and/or persons selecting such products should verify all facts relative to the particular project requirements.
To fully understand how to choose an appropriate cork flooring material and method of installation for a residential, commercial, or institutional project, a thorough knowledge of the materials and installation requirements is essential. The following information will hopefully assist Designers, Suppliers, Installers, Owners, and others in becoming more aware of cork flooring issues and aid in choosing a cork flooring material and an installation method to suit a project's requirements. 1 •
GENERAL COMMENTS
.01 Cork floor coverings must meet Code requirements in regard to flame spread and smoke developed ratings with the ratings dependent on the type of occupancy. For information on flammability refer to Part A08A - Flammability Issues.
.02 For specific information of reference standards noted herein refer to F02B - Reference Guide - Standards.
This study guide covers cork flooring and related materials. The information given is a guide only and cannot fully cover all aspects of such flooring and its installation. Specifiers and/or persons selecting such products should verify all facts relative to the particular project requirements.
To fully understand how to choose an appropriate cork flooring material and method of installation for a residential, commercial, or institutional project, a thorough knowledge of the materials and installation requirements is essential. The following information will hopefully assist Designers, Suppliers, Installers, Owners, and others in becoming more aware of cork flooring issues and aid in choosing a cork flooring material and an installation method to suit a project's requirements. 1 •
GENERAL COMMENTS
.01 Cork floor coverings must meet Code requirements in regard to flame spread and smoke developed ratings with the ratings dependent on the type of occupancy. For information on flammability refer to Part A08A - Flammability Issues.
.02 For specific information of reference standards noted herein refer to F02B - Reference Guide - Standards.
2 • CORK UNDERLAYMENT FOR FLOORING
.01 Cork Underlayment: This is a sheet material of agglomerated cork used as an acoustical and/or an isolation underlayment under hard surface flooring such as hardwood, laminate, bamboo, and even ceramic tile floors.
There are a million cork cells per cubic inch in cork. Each cell is a dead air space that impedes the transmission of sound and therefore serves as an effective noise barrier. This unique physical characteristic also gives cork excellent compressibility and recoverability. It easily conforms to slight variations in the surface of the floor and provides a compliant base for finished flooring. For addition characteristics of cork refer to Part F03B2.
Cork underlayment is formulated from specific sized natural cork granules that are compressed together to provide specific densities to suit requirements from 190 kg/m3 to 210 kg/m3 (11.7 lb/ft3 to 12.5 lb/ft3) and is available in roll form in a number of thicknesses and widths as noted below.
.01 Cork Underlayment: This is a sheet material of agglomerated cork used as an acoustical and/or an isolation underlayment under hard surface flooring such as hardwood, laminate, bamboo, and even ceramic tile floors.
There are a million cork cells per cubic inch in cork. Each cell is a dead air space that impedes the transmission of sound and therefore serves as an effective noise barrier. This unique physical characteristic also gives cork excellent compressibility and recoverability. It easily conforms to slight variations in the surface of the floor and provides a compliant base for finished flooring. For addition characteristics of cork refer to Part F03B2.
Cork underlayment is formulated from specific sized natural cork granules that are compressed together to provide specific densities to suit requirements from 190 kg/m3 to 210 kg/m3 (11.7 lb/ft3 to 12.5 lb/ft3) and is available in roll form in a number of thicknesses and widths as noted below.
- Dimensions: Consult cork flooring manufacturer and local distributor for product thicknesses, widths, and availability. Common sizes are as follows: 3 mm (1/8"), 6 mm (1/4"), 13 mm (1/2") thick x 1200 (48") and 915 mm (36") wide in sheet and roll form.
- Special Note: Cork underlayment is not a waterproof membrane.
- Caution: Cork underlayment is not recommended over wood subfloors that are not adequately vented, over on grade or below grade concrete slabs, or over concrete slabs subjected to hydrostatic pressure unless an approved vapour barrier is used under the slab. All such cases are also subject to flooring manufacturer's pre-approval.
3 • CORK FLOORING PREPARATION MATERIALS
.01 Panel Type Underlayment: Refer to Part A10 - Acceptable Conditions for information and requirements. Refer also to ASTM F1482, Standard Guide to Wood Underlayment Products Available for Use Under Resilient Flooring.
.02 Patching, Filling, and Levelling Compounds: Refer to Part A13 - Patching and Filling for information and requirements.
.03 Primers: Refer to Part A12 - Substrate Preparation for requirements of primers over patching and filling compounds.
.01 Panel Type Underlayment: Refer to Part A10 - Acceptable Conditions for information and requirements. Refer also to ASTM F1482, Standard Guide to Wood Underlayment Products Available for Use Under Resilient Flooring.
.02 Patching, Filling, and Levelling Compounds: Refer to Part A13 - Patching and Filling for information and requirements.
.03 Primers: Refer to Part A12 - Substrate Preparation for requirements of primers over patching and filling compounds.
- Primers are no longer required for most installations. Consult with specific cork flooring material and adhesive manufacturers to be used for applicability and requirements.
- Primers are not designed to act as waterproofing agents, and should only be specified for a specific purpose or installation system.
4 • ADHESIVES
.01 The type and application of adhesives shall be as recommended by both the cork flooring and adhesive manufacturers to suit the substrate type, the type of cork flooring, and the type of application required.
.02 As cork tile will expand and contract with humidity changes much like hardwood, selecting a "strong" adhesive that creates an instant and permanent bond is important. Unless the adhesive creates an instant bond, the moisture in the adhesive is likely to cause the tile to expand during the drying period which can result in raised corners. Re-adhering lifted tile edges is difficult.
.03 Using a water-based contact cement has proven most effective in the installation of cork tile flooring. The contact cement is applied to both the substrate and the back of cork tile and then allowed to dry completely (approximately 40 minutes). The tile is then carefully positioned by lightly placing it on the substrate and moving it into place. Once pressed to the substrate the tile is permanently bonded and cannot be moved.
.04 Refer to Part A14 - Adhesives and Fasteners for adhesive types.
.05 Caution: The design authority / specification writer is cautioned against specifying a particular type or manufacturer of adhesive as each cork flooring manufacturer may have specific recommendations in regard to the type and usage of adhesives for their particular products and installations. The National Floor Covering Association (NFCA) therefore recommends that the Design Authority specify adhesives "as recommended by the flooring material manufacturer to suit installation requirements". The grade (standard or premium) and the type (based on VOC content) as well as use of water resistant or water proof types should however be specified.
.06 LEED Requirements: Where the flooring installation must conform to LEED requirements, the type of adhesives used throughout (i.e. for installation of underlayment panels, flooring, bases, and accessories) shall be governed by those requirements.
.01 The type and application of adhesives shall be as recommended by both the cork flooring and adhesive manufacturers to suit the substrate type, the type of cork flooring, and the type of application required.
.02 As cork tile will expand and contract with humidity changes much like hardwood, selecting a "strong" adhesive that creates an instant and permanent bond is important. Unless the adhesive creates an instant bond, the moisture in the adhesive is likely to cause the tile to expand during the drying period which can result in raised corners. Re-adhering lifted tile edges is difficult.
.03 Using a water-based contact cement has proven most effective in the installation of cork tile flooring. The contact cement is applied to both the substrate and the back of cork tile and then allowed to dry completely (approximately 40 minutes). The tile is then carefully positioned by lightly placing it on the substrate and moving it into place. Once pressed to the substrate the tile is permanently bonded and cannot be moved.
.04 Refer to Part A14 - Adhesives and Fasteners for adhesive types.
.05 Caution: The design authority / specification writer is cautioned against specifying a particular type or manufacturer of adhesive as each cork flooring manufacturer may have specific recommendations in regard to the type and usage of adhesives for their particular products and installations. The National Floor Covering Association (NFCA) therefore recommends that the Design Authority specify adhesives "as recommended by the flooring material manufacturer to suit installation requirements". The grade (standard or premium) and the type (based on VOC content) as well as use of water resistant or water proof types should however be specified.
.06 LEED Requirements: Where the flooring installation must conform to LEED requirements, the type of adhesives used throughout (i.e. for installation of underlayment panels, flooring, bases, and accessories) shall be governed by those requirements.
5 • CORK FLOORING
.01 Cork Flooring: Cork flooring is manufactured from agglomerated (granular) cork particles from the bark of the cork oak tree. The particles are sorted for uniformity, mixed with a binder, and compressed under heat and pressure into slabs that are then cut into various thicknesses and sizes.
Note: This type of flooring may be classified by some as wood flooring because of its material composition (fabricated from cork tree bark) or as a resilient flooring because of its resilience and tile form that is similar to resilient tile.
.02 Cork Flooring Performance:
.01 Cork Flooring: Cork flooring is manufactured from agglomerated (granular) cork particles from the bark of the cork oak tree. The particles are sorted for uniformity, mixed with a binder, and compressed under heat and pressure into slabs that are then cut into various thicknesses and sizes.
Note: This type of flooring may be classified by some as wood flooring because of its material composition (fabricated from cork tree bark) or as a resilient flooring because of its resilience and tile form that is similar to resilient tile.
- Applicable Standards:
- ASTM WK7115, New Standard Specification for Cork Tile Flooring.
- ASTM WK10811, New Standard Specification for Cork Tile Flooring.
- EN 655, Resilient floor coverings - Tiles of agglomerated composition cork with polyvinyl chloride wear layer. Specification.
- EN 672, Resilient floor coverings - Determination of apparent density of agglomerated cork.
- EN12104 / ISO 3813, Resilient floor coverings, Cork floor tiles, Specification.
- EN 12103, Resilient floor coverings - Agglomerated cork underlays - specification.
- EN 12104, Resilient floor coverings - Cork floor tiles - Specification.
- EN 12105, Resilient floor coverings - Determination of moisture content of agglomerated composition cork.
- Types: Cork flooring is available in two forms each fabricated from various sized cork granules (typical) or from large size cork pieces (which result in solid cork units) that are compressed together.
- Cork Tile Flooring: This is the primary and original form of cork flooring and is available with or without beveled edges and attached backing. Tiles are available in massive form (i.e., same pattern all the way through) or with a veneer surface pattern. For commercial applications that may involve future refinishing, massive tiles are recommended as they can be sanded and refinished.
- Engineered Cork Flooring: This is a relatively new innovation in cork flooring and the result of consumer demand. This type of flooring is fabricated much the same as laminate flooring with a top layer of agglomerated cork, a centre core layer of water resistant medium density (MDF) or high density (HDF) fibreboard, and a bottom balancing layer of cork for stability. Planks are available in various widths and lengths depending on the manufacturer and come with tongue and groove side and end joints and with square or bevelled joints edges. Consult cork plank manufacturer for sizes, finishes, and construction available.
- Dimensions: Consult cork flooring manufacturer and local distributor for product gauges, widths, and availability. Common sizes are as follows:
- Tile sizes: nominal sizes:
- Square tiles: 150 mm (6"), 200 mm (8"), 300 mm (12"), and 600 mm (24")
- Rectangular tiles: 150 mm (6"), 230 mm (9"), 300 mm (12") and 460 mm (18") x 230 mm (9"), 300 mm (12"), 460 mm (18"), and 600 mm (24").
- Special tiles: triangular, diamond, and pentagonal (6-sided) for patterns.
- Thicknesses: 3 mm (1/8"), 4 mm (5/32"), 4.76 mm (3/16"), 7.94 mm (5/16"), 10 mm (3/8") thick. Laminated parquet tiles may be thicker, i.e. 11 mm (7/16") and 13 mm (1/2").
- Plank sizes: 190 mm (7 1/2"), 300 mm (12") wide x 900 mm (36") long x 11 mm (7/16") and 13 mm (1/2") thick.
- Colours: Cork flooring may be left in its natural colour or may be factory stained in a variety of colours. Some shade variation is an inherent and attractive characteristic of natural cork. Both natural and stained cork may change colour when exposed to sunlight over prolonged periods of time, i.e., cork will tend to fade while most hardwoods for example will darken / mellow. These subtle colour changes do not take way from the beauty of these materials and cork flooring under normal wear and proper installation / maintenance, may last upwards of 30 years.
- Finishes: Cork may be factory finished or left unfinished ready for site finishing after installation.
- Pre-Finished Flooring: The top (exposed) face of cork tile or plank is lightly sanded and factory finished with clear polyurethane or unfilled acrylic vinyl top coats that may also have aluminum oxide or ceramic granules added for increased wear resistance and durability. Prior to finishing, cork flooring units are either natural or may be stained a variety colours.
- Unfinished Flooring: The top (exposed) face of cork tile or plank is lightly sanded and left ready for a site applied finish (such as clear polyurethane or acrylic, or wax). For acceptable on-site finishing materials and methods contact the manufacturer. Using unacceptable materials and methods may void flooring warranties.
- Advantages: Cork flooring has excellent impact and acoustic qualities, is very resilient, provides excellent underfoot warmth, and meets LEED requirements. Cork flooring can be installed on all permanently dry substrates.
- Caution: Cork flooring is unfavourably effected by moisture and alkali influences, and should therefore not be used on substrates where moisture emissions and alkali levels exceed the manufactures maximum levels allowed.
- Special Note: Local availability may be limited. Contact local dealer for availability of styles, colours, and quantities.
.02 Cork Flooring Performance:
- Density: 550 kg/m 3 (34 lbs/ft3).
- Flammability: (to ASTM E648) Class 2 for pre-finished, Class 1 for unfinished.
- Smoke Density: (to ASTM E662 / NFPA 258) Flaming: 148, Non Flaming: 272.|
- Compression Recovery: (to ISO 9727) with loading of 38.5 lbs/in2: Initial: 10%, residual: 1.5% after 1 hour.
- Thermal Resistance: (to ASTM C518) thermal conductivity (k) 0.3490, thermal resistance (r) 0.49, thermal resistance per inch 2.87.
- Permeance: (to ASTM E96) 0.183 perms.