A14 - ADHESIVES AND FASTENINGS
A14-1 Adhesives
A14-2 Adhesive types
A14-3 Adhesive application and trowel notch sizes
A14-4 Adhesive performance
A14-5 Fasteners
A14-6 Specifying adhesives and fasteners
A14-2 Adhesive types
A14-3 Adhesive application and trowel notch sizes
A14-4 Adhesive performance
A14-5 Fasteners
A14-6 Specifying adhesives and fasteners
1 • ADHESIVES
.01 The term adhesive (sometimes referred to as cement) applies to those materials used to bond one material (such as flooring, bases, and accessories) to another (such as substrate surfaces) by chemical attachment. Adhesive also includes seam welding agents as well as bonding primers (used to improve bond of subsequent adhesive) and adhesive primers (used to provide a bondable surface).
.02 The correct selection and application of adhesives is essential for the successful installation and durability of flooring covering materials. In many cases the floor covering manufacturer either recommends generic types of adhesives manufactured by others (third parties) or develops and/or distributes their own adhesives that are specifically designed for use with their products. In some cases flooring manufacturers require the use of specific adhesive products as part of their warranty requirements.
.03 Caution: Some flooring contactors don't always use adhesives recommend by the manufacturer or use some private label, inexpensive, or low quality adhesive from other sources. In other cases flooring contractors may reject adhesives recommended by a manufacturer because of working properties. In addition some flooring distributors may know very little when it comes to flooring installation and therefore may not provide appropriate adhesives to meet project requirements. The installation accessory distributors in Canada are significantly more knowledgeable in regard to flooring adhesives and are more geared to proving appropriate adhesives (this is where the installers and contract flooring companies purchase installation supplies). Finally, some flooring suppliers may not provide a complete line of floor preparation products, i.e., patching and levelling compounds, screeds, moisture barriers, etc. and hence are not able to provide a complete installation system.
.04 If an incorrect adhesive is used a flooring installation may fail completely. Flooring contractors must therefore be aware of the properties of the adhesives that may be used and the substrate and environmental conditions and limitations that apply for the use of each. They must also be aware of the generic types and grade / quality levels of applicable adhesives as well as be well versed in the variety of adhesive manufacturers and the names used to market their various products. This also entails being able to compare brands and knowing what brands can be substituted for another.
.05 Caution Note: The design authority / specification writer is cautioned against specifying a particular type or manufacturer of adhesive as each floor covering manufacturer may have specific recommendations in regard to the type and usage of adhesives for their particular products and installations. Refer to item 6 following.
.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. Water based adhesives used to comply with LEED requirements must not contain volatile organic compounds in excess of 5% by weight as measured by:
.01 The term adhesive (sometimes referred to as cement) applies to those materials used to bond one material (such as flooring, bases, and accessories) to another (such as substrate surfaces) by chemical attachment. Adhesive also includes seam welding agents as well as bonding primers (used to improve bond of subsequent adhesive) and adhesive primers (used to provide a bondable surface).
.02 The correct selection and application of adhesives is essential for the successful installation and durability of flooring covering materials. In many cases the floor covering manufacturer either recommends generic types of adhesives manufactured by others (third parties) or develops and/or distributes their own adhesives that are specifically designed for use with their products. In some cases flooring manufacturers require the use of specific adhesive products as part of their warranty requirements.
.03 Caution: Some flooring contactors don't always use adhesives recommend by the manufacturer or use some private label, inexpensive, or low quality adhesive from other sources. In other cases flooring contractors may reject adhesives recommended by a manufacturer because of working properties. In addition some flooring distributors may know very little when it comes to flooring installation and therefore may not provide appropriate adhesives to meet project requirements. The installation accessory distributors in Canada are significantly more knowledgeable in regard to flooring adhesives and are more geared to proving appropriate adhesives (this is where the installers and contract flooring companies purchase installation supplies). Finally, some flooring suppliers may not provide a complete line of floor preparation products, i.e., patching and levelling compounds, screeds, moisture barriers, etc. and hence are not able to provide a complete installation system.
.04 If an incorrect adhesive is used a flooring installation may fail completely. Flooring contractors must therefore be aware of the properties of the adhesives that may be used and the substrate and environmental conditions and limitations that apply for the use of each. They must also be aware of the generic types and grade / quality levels of applicable adhesives as well as be well versed in the variety of adhesive manufacturers and the names used to market their various products. This also entails being able to compare brands and knowing what brands can be substituted for another.
.05 Caution Note: The design authority / specification writer is cautioned against specifying a particular type or manufacturer of adhesive as each floor covering manufacturer may have specific recommendations in regard to the type and usage of adhesives for their particular products and installations. Refer to item 6 following.
.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. Water based adhesives used to comply with LEED requirements must not contain volatile organic compounds in excess of 5% by weight as measured by:
- EPA Method 24-24A, 40 C.F.R., Part 60, Appendix A (1991),
- Method 18,48 Federal Register 48, no. 202, October 18, 1983,
- Method 1400 NIOSH Manual of Analytical Methods, Volume 1, February 1984,
- Environmental Protection Agency Method 8240 GC/MS Method for Volatile Organics, September 1986; or
- As demonstrated through calculation from records of the amounts of constituents used to make the product.
2 • ADHESIVE TYPES
.01 The type and application of adhesives shall be as recommended by both the material and adhesive manufacturer to suit the substrate type, the type of resilient flooring and the type of application required.
.02 There are a variety of adhesive types available to adhere floor coverings to substrate surfaces and to adhere their seams / joints together. These fall into four main chemical property categories:
.03 Adhesives may also be categorized by types that include:
.04 Within each family of adhesives, there is a range of specific products. Many are proprietary. For adhesives applicable to each flooring type refer to Parts B04C, C04C, C04D, D04C, E04C, and F04C.
.05 Caution: Refer to LEED requirements noted herein when using any of the above types.
.01 The type and application of adhesives shall be as recommended by both the material and adhesive manufacturer to suit the substrate type, the type of resilient flooring and the type of application required.
.02 There are a variety of adhesive types available to adhere floor coverings to substrate surfaces and to adhere their seams / joints together. These fall into four main chemical property categories:
- SBR-Based Adhesives: Styrene butydene rubber adhesives may be either solvent or water borne and are generally used to install carpets although other types may be used in some circumstances.
- Acrylic Emulsion Adhesives: may be either solvent or water borne and are generally used to install vinyl products.
- Reactive Adhesives: this type of adhesive may be either epoxy or urethane based and requires on-site mixing of compounds which must then be applied within a specified time period.
- Epoxy Adhesives: A two-component (resin and catalyst) epoxy adhesive, with excellent surface water resistance and high bond strength. Components must be thoroughly mixed before using.
- Uses: may be used with rubber tile and sheet goods, conductive tile, securing seams or joints around drains etc., areas that receive occasional surface water spillage and perimeter flooring installation systems.
- Caution: Although most epoxy adhesives are water washable low VOC types some may be toxic and/or may pose a problem in regard to skin sensitivity and therefore require care in use. Consult manufacturers' MSDS and installation instructions.
- Remarks: Consult floor covering manufacturers product requirements for the particular type of epoxy adhesive recommended.
- Polyurethane Adhesives: A two-component (resin and catalyst) polyurethane adhesive with excellent surface water resistance and high bond strength. Components must be thoroughly mixed before using.
- Uses: may be used with the following
- rubber / vinyl tile and sheet goods.
- flexible PVC sheet goods.
- areas that receive occasional water spillage.
- safety flooring installations.
- sports flooring installations.
- securing seams or joints around drains etc.
- in locations or situations where an extra strong bond is desirable.
- Where Used: On all types of concrete substrates, above, on, and below grade level and over approved plywood / wood underlayment panels.
- Caution: Some polyurethane adhesives are very toxic and therefore require extreme care in use. Consult manufacturers application instruction and adhere to MSDS requirement.
- Remarks: Consult floor covering manufacturers product requirements for the particular type of polyurethane adhesive recommended.
- Uses: may be used with the following
- Epoxy Adhesives: A two-component (resin and catalyst) epoxy adhesive, with excellent surface water resistance and high bond strength. Components must be thoroughly mixed before using.
- Polychloroprene (neoprene) Adhesives: this type of adhesive is used for special applications.
.03 Adhesives may also be categorized by types that include:
- Linoleum Adhesive: There are two types, both of which are specifically formulated for the installation of linoleum sheet and tile flooring.
- Water-Soluble Linoleum Adhesive: A light coloured water-soluble adhesive with good bonding qualities. Note: This may no longer be used or available.
- Water-Resistant Linoleum Adhesive: A light coloured, surface water/alkali resistant adhesive with good bonding qualities.
- Where Used: Over all permanently dry wood or concrete substrates.
- Contact Adhesive: A site applied adhesive that dries to a film that is tack free to certain materials but not to itself, i.e., it is dry to the touch but will adhere instantaneously to itself upon contact. The term contact bond adhesive or dry bond adhesive is also used. There are two types:
- Solvent-Base Type: The use of this type may be restricted due to environmental and LEED requirements. This type is most often used (if LEED is not a requirement) because it flashes off faster.
- Water-Base Type: a water-soluble type.
- Uses: contact adhesives may be used with the following:
- Cork tile installations.
- Top-set base - corner installations.
- Flash coving (cove former / capping / corner installations).
- Stair covering (stringer / nosing / tread installations).
- Wall covering (corner bonding).
- Door transition strip installations.
- Linoleum counter top material installations.
- Where Used: On all types of concrete substrates, above, on, and below grade level and over approved plywood / wood underlayment panels.
- Thin-Spread Adhesives: There are two types:
- Asphalt Latex-Base Adhesive: A fast setting permanently tacky asphalt latex base adhesive that retains its plasticity indefinitely and emits no toxic fumes.
- Synthetic Resin-Base Adhesive: A fast setting light-coloured adhesive that is permanently tacky and retains its plasticity indefinitely and dries to a clear film.
- Uses: For vinyl composition tile (VCT).
- Where Used: Over all industry approved concrete and wood substrates.
- Caution: Keep from freezing. Follow manufacturer's installation instructions.
- Multiple-Use Adhesives: There are two basic types:
- Tack Bond or Pressure Sensitive Adhesives: Fast set light-coloured latex / acrylic base adhesive that cures to a clear film.
- Uses: May be used with homogeneous vinyl tile, non-mineral, fibre-backed vinyl sheet goods, and flooring products requiring a tack bond only.
- Where Used: Over all industry approved concrete or wood substrates.
- Wet Bond, Wet-Set, or Permanent Bond Adhesives: (multi-purpose types) A Light-coloured, water resistant latex / acrylic base adhesive with excellent bonding qualities.
- Uses: may be used with the following
- Mineral felt-back sheet goods.
- Felt-back sheet goods.
- Solid vinyl products.
- Foam back products.
- Rubber products
- Where Used: On or below grade wood and concrete substrates.
- Uses: may be used with the following
- Caution: Keep from freezing. Follow manufacturer's installation instructions.
- Remarks: A number of floor covering products require the use of specially formulated latex/acrylic base adhesives to suit their products' characteristics. Consult flooring dealer for types and availability.
- Tack Bond or Pressure Sensitive Adhesives: Fast set light-coloured latex / acrylic base adhesive that cures to a clear film.
- Alcohol Resin-Based Adhesives: Brown coloured, water resistant adhesive, made from natural and synthetic resins, inert fillers, and denatured alcohol.
- Uses: May be used with solid vinyl and rubber products, cork tile.
- Where Used: Above grade / suspended wood and concrete substrates.
- Caution: Provide adequate ventilation. Follow recommended safety cautions.
- Hot-Melt Adhesive: A specially formulated adhesive placed on the back of floor tile so that the tile can be installed without having to use any other adhesive. Tile with this type of adhesive is commonly referred to as peel-and-stick or place-n-press tile sold to the do-it-yourself (DIY) market.
- Top-Set Base Adhesive: This type may be used for:
- Rubber / vinyl resilient base installations.
- Stair tread installations.
- Other rubber / vinyl speciality product installations.
- Perimeter Adhesive: for specified perimeter flooring installations.
- Conductive Adhesive: for dissipative / conductive flooring installations.
- Stair-Nose Adhesive: for filling cavities at nose of stair and to increase strength at nose of stair tread.
- Seam Sealer: for sealing / coating seams in flooring when specified.
.04 Within each family of adhesives, there is a range of specific products. Many are proprietary. For adhesives applicable to each flooring type refer to Parts B04C, C04C, C04D, D04C, E04C, and F04C.
.05 Caution: Refer to LEED requirements noted herein when using any of the above types.
3 • ADHESIVE APPLICATION AND TROWEL NOTCH SIZES
.01 The appropriate adhesive and trowel notch size shall be as recommended by resilient flooring and adhesive manufacturers.
.02 The trowel notch must be large enough to apply a continuous film (i.e. full coverage) of the adhesive to the substrate to ensure a minimum 90% transfer of the adhesive to the resilient floor backing.
.03 Adhesives must be spread uniformly over the substrate surface using the correct trowel and adhesive spread rate and technique recommended by the manufacturer for the type of substrate and flooring used. The flooring is then installed over the adhesive and rolled with an appropriate roller to ensure full contact of the adhesive.
.01 The appropriate adhesive and trowel notch size shall be as recommended by resilient flooring and adhesive manufacturers.
.02 The trowel notch must be large enough to apply a continuous film (i.e. full coverage) of the adhesive to the substrate to ensure a minimum 90% transfer of the adhesive to the resilient floor backing.
.03 Adhesives must be spread uniformly over the substrate surface using the correct trowel and adhesive spread rate and technique recommended by the manufacturer for the type of substrate and flooring used. The flooring is then installed over the adhesive and rolled with an appropriate roller to ensure full contact of the adhesive.
4 • ADHESIVE PERFORMANCE
.01 While an adhesives performance will vary from manufacturer to manufacturer as well as within a manufacturer's own product line (e.g. premium vs. economy grade), manufacturing variables do not explain the performance differences noted from job to job and day to day when the same adhesive is used.
.02 Adhesive problems that may be encountered are:
.03 There are a number of variables encountered in the field that affect adhesive performance and set up time. The following are six factors, listed in order of significance, that influence adhesive performance (set up time):
.01 While an adhesives performance will vary from manufacturer to manufacturer as well as within a manufacturer's own product line (e.g. premium vs. economy grade), manufacturing variables do not explain the performance differences noted from job to job and day to day when the same adhesive is used.
.02 Adhesive problems that may be encountered are:
- It is not drying.
- It is drying too quickly.
- It is not holding the flooring material in place.
- It is not sticking or it is still wet.
- It is not transferring to the floor covering backing.
- It worked well yesterday but is not working right today.
- It is not as good as the last batch purchased.
.03 There are a number of variables encountered in the field that affect adhesive performance and set up time. The following are six factors, listed in order of significance, that influence adhesive performance (set up time):
- Substrate Porosity: (The ability of the substrate surface to absorb moisture from the adhesive.)
- Porous subfloors generally require less set up time than non-porous. Expect at least double the set up time when installing over non-porous floors like sealed concrete, terrazzo and marble, and linoleum tile as compared to porous floors such as plywood and suspended or unsealed concrete.
Recommendation: Allow longer adhesive open time, circulate air with fans, decrease room humidity when installing over non-porous substrates.
Note: The use of sealers, primers, curing compounds, etc. could render a porous substrate non-porous and in some cases void an adhesive manufacturer's warranty. Verify with adhesive and flooring manufacturer if such materials are to be removed before the application of adhesive and flooring.- Humidity: (The amount of moisture in the air at a given temperature.)
- The relative humidity influences the rate the moisture can evaporate from the adhesive. The higher the humidity, the longer the set up time. NFCA recommends that the humidity not exceed 65% during any floor covering installation. Expect double the adhesive set up time when installing floor covering over a non-porous substrate at 75% relative humidity compared to 25% relative humidity.
Recommendation: Allow longer adhesive open time, dehumidify air, increase room temperature, and provide air circulate.- Floor Covering Backings:
- The more non-porous the floor covering, the longer the adhesive set up time. Expect longer adhesive set up times when installing materials with synthetic backings (e.g. vinyl backings) as compared to porous backings (e.g. jute and mineral fibrous felt backings).
Recommendation: Allow longer adhesive open time with non-porous floor covering backing, increase room temperature, and reduce humidity. Ideally use a floor covering with a porous backing over an existing non-porous substrate.- Trowels:
- The type of trowel (material) and notch sizing for adhesive applications must be as recommended by both the flooring and adhesive material manufacturers. This variable cannot be changed. In addition, the correct application technique and resultant amount of adhesive "transferred" to the material backing is critical in achieving a successful flooring installation. The substrate surface may also have a bearing on adhesive transfer. The deeper and wider trowel notches are, the greater the amount of adhesive that will be used and the longer the adhesive set up time will be. Adhesive transfer should be a minimum of 85% to ensure positive adhesion of any flooring material.
Note: Less adhesive should not be used to speed up the adhesive set up time. This will only result in loss of adhesion over time. Conversely more adhesive is not good either as it will take longer to set up and will ooze up between seams and/or around flooring edges.
Caution: Incorrect trowel selection and lack of adhesive transfer is a significant cause of flooring failures. Adhesive transfer must be verified.- Temperature of the Adhesive:
- The colder the adhesive, the longer the set up time. Adhesive at 5°C (40°F) will set up considerably longer than at 21°C (70°F). Additionally, at 5°C (40°F) the adhesive will be thicker and more unstable over a concrete substrate.
Recommendation: Condition the installation site, all flooring materials, and the adhesive at 21°C (70°F).- Open Time or Pot Life: This is the amount of time an installer has before the adhesive no longer transfers to the floor covering backing.
- When installing a non-porous backed floor covering or when installing over a non-porous substrate, allow the adhesive longer open time.
Recommendation: If the adhesive appears to have an unusually long open time, expect a long adhesive set up time. The same variables that affect adhesive set up time will affect the adhesive open time.
Understanding these variables may help to explain why the same adhesive that worked well yesterday did not set up the same way today.
.05 Note: The General Contractor / Construction Manager must provide substrate and environmental conditions that are acceptable for flooring (and adhesive) installation in accordance with NFCA minimum requirements.
5 • FASTENERS
.01 Fasteners used with resilient, carpet, hardwood, and laminate floor coverings and their accessories vary greatly. Generally speaking however they all should be non-corrosive and of types as recommended by the flooring / accessory manufacturer to suit the flooring material and substrate conditions.
.02 Fasteners may be nails, tacks, cleats, staples, or screws or may be clips and pins for specialty flooring (e.g. some hardwood and laminate flooring systems) and are specific to the type of flooring material.
.03 For specific fastener types refer to each flooring specification section.
.01 Fasteners used with resilient, carpet, hardwood, and laminate floor coverings and their accessories vary greatly. Generally speaking however they all should be non-corrosive and of types as recommended by the flooring / accessory manufacturer to suit the flooring material and substrate conditions.
.02 Fasteners may be nails, tacks, cleats, staples, or screws or may be clips and pins for specialty flooring (e.g. some hardwood and laminate flooring systems) and are specific to the type of flooring material.
.03 For specific fastener types refer to each flooring specification section.
6 • SPECIFYING ADHESIVES AND FASTENERS
.01 As previously noted, the design authority / specification writer is cautioned against specifying a particular manufacturer or type of adhesive or fastener as each flooring manufacturer may have specific recommendations in regard to the type and usage of adhesives and fasteners for their particular products and installations. The National Floor Covering Association (NFCA) therefore recommends that the Design Authority specify adhesives or fasteners "as recommended by the flooring manufacturer to suit installation requirements". In regard to adhesives the grade (standard or premium), type (water-resistant or water-proof), and if applicable, the VOC content (i.e., solvent-based or water-based) must be noted.
.02 Where a project is to meet LEED requirements any adhesives and adhesive primers as well as sealant and sealant primers used in adhering underlayments, fastening flooring, bases, and accessory materials to substrate surfaces, and adhering flooring materials to each other shall meet LEED VOC requirements in accordance with rule 1168 of the South Coast Air Quality Management District (SCAQMD). For specific VOC levels refer to specific floor covering Part sections.
.01 As previously noted, the design authority / specification writer is cautioned against specifying a particular manufacturer or type of adhesive or fastener as each flooring manufacturer may have specific recommendations in regard to the type and usage of adhesives and fasteners for their particular products and installations. The National Floor Covering Association (NFCA) therefore recommends that the Design Authority specify adhesives or fasteners "as recommended by the flooring manufacturer to suit installation requirements". In regard to adhesives the grade (standard or premium), type (water-resistant or water-proof), and if applicable, the VOC content (i.e., solvent-based or water-based) must be noted.
.02 Where a project is to meet LEED requirements any adhesives and adhesive primers as well as sealant and sealant primers used in adhering underlayments, fastening flooring, bases, and accessory materials to substrate surfaces, and adhering flooring materials to each other shall meet LEED VOC requirements in accordance with rule 1168 of the South Coast Air Quality Management District (SCAQMD). For specific VOC levels refer to specific floor covering Part sections.