Adhesives & Caulking
by Christi Graham
What are they?
Adhesives are a category of building materials that tend to be overlooked and often selected at the last minute. However, adhesive choices can have a significant impact on our indoor air quality and are often times more potentially dangerous than the flooring and other products they are made to adhere.
There are many different types of adhesives, but the majority are based on SB latex, the same resin used in carpet backing. With such a large volume used, adhesives have generally been the greatest source of short-term volatile organic compound (VOC) emissions - but change is underway!
Although "true" solvent based adhesives have not been used since 1970, most adhesives have continued to use volatile solvents to emulsify (or liquefy) the resin that acts as the bonding agent. Increasing consumer awareness has inspired adhesive manufacturers to find ways to reduce solvent levels, and now many offer products with a calculated VOC level of zero. This has been accomplished by using heat or other processes instead of solvents to emulsify the resin. As a general rule, water-based adhesives emit far less VOC's than their conventional solvent based counterparts. Several manufacturers, including the W.F. Taylor Company and the Henry Company now sell only low and no VOC products. Exciting new research is also being conducted as to the effectiveness of starch-oil based adhesives, which we should see entering the market stream within the next several years.
While some products are sold as multi-purpose, others are specific to a particular application or product. If a flooring manufacturer recommends a specific low or no VOC water-based product for use with it's material, it would be wise to follow their suggestion. Otherwise, consider products that will minimize indoor air pollution and make everyone breathe a little easier
Adhesives are used most commonly for gluing down carpeting and other flooring surfaces such as cork and tile. Adhesives are also used in the installations of cabinetry, countertops, sub flooring, wainscoting and plywood decorative paneling. Caulking is also included in this category as it is used both as an adhesive and as a sealant. Caulking is used on baseboards, windows, tubs, sinks, moldings and anywhere wood comes in contact with plaster.
Again, adhesives are a strong potential for introducing more VOC's into the air, especially on a short-term basis. Select low or non-toxic water-based products for these purposes. Certain manufactures offer no-VOC adhesives (<10 gms/ltr). Also look for products made without formaldehyde.
Solvent-based adhesives should be treated as hazardous waste and disposed of accordingly.
Surface Preparation - All substrates to receive adhesive and overlays must be sound and intact. Any loose areas should be repaired or anchored to produce a firm footing for adhesion. All surfaces must be cleaned of any grease, oils, dust, dirt, wax, old adhesives and other foreign materials. Washing with a nontoxic cleaner is recommended. The surface must be completed dry prior to application. For maximum adhesion apply a thin coating of sealer to the substrate and if possible the back of the material before spreading adhesive. This helps provide a moisture barrier and is particularly important for parquet and wooden flooring, which varies in consistency and may have a tendency to warp.
Application - Always have adequate ventilation. Due to rapid curing tendencies do not spread the adhesive over areas larger than 16-20 square feet. Allow adhesive to "tack up" for a few minutes (typically not more than 10 to 15 minutes depending on temperature and humidity) and then place flooring material onto mastic. Maintain a wet, tacky surface during installation of the tile. Do not allow adhesive to skim over. If a film forms, the adhesive skims over or sets up so that it is no longer sticky, scrape all adhesive off the surface and reapply. Allow 24 hours for curing before allowing any traffic on the area.
Performance / Durability
Early generations of low VOC adhesives were not as superior to the ones on the market now. Now, in some cases low-VOC adhesives are actually superior in their ability to adhere in the most difficult circumstances.
Who Makes It?
Titebond Construction Adhesive - by Franklin International, is a solvent free construction adhesive (no VOC's) for plywood, paneling, hardboard and wet or frozen lumber.
Timberline 2051 Wood Flooring Adhesive - by Timberline for laminated plank and parquet flooring
PL/OSI line of adhesives - by OSI Sealants Inc. low VOC adhesives including SF-565 Voc compliant construction adhesive.
Elmer's Carpenter's Glue - by good ol' Elmer's is a low odor, non toxic water based adhesive for porous materials
100% Pure Silicone Caulk - by DAP/Dow Corning Products can be used as a sub floor adhesive. Specify aquarium grade caulk without additives. Available at many hardware chains including Home Depot, Ace Hardware.
NATURAL CORK AND LINOLEUM ADHESIVES
Safecoat 3 in 1 Adhesive - by AFM is a low odor, non-toxic, water-based adhesive designed for hard composition wall and floor tiles as well as carpeting. (ceramic, parquet, Formica and slate where a typical carpet adhesive would be used.
Auro No. 383 Natural Linoleum Glue - by Auro is suitable for unfinished cork tiles in a thin bed application, but not suitable for floors in humid areas.
Bio shield cork adhesive - is a water-based elastic glue made from natural latex, plant oils and resins designed for use with cork and carpets. Can be used on finished concrete wood and plywood.
Envirotec Health Guard adhesive
Dri-Tac - is a water-based low VOC adhesive that claims superior tack. This product is recommended by Dodge-Regopol natural cork flooring manufacturers.
CERAMIC TILE ADHESIVES
CT-12 - by Capitol Adhesives is a solvent-free mastic for installing ceramic wall and floor tiles.
CARPET ADHESIVES AND SEAMING TAPES
Almighty Adhesive - by AFM is low odor, non-toxic, water based adhesive for gluing wood and wood laminates
Auro No. 385 Natural Carpet Glue - by Auro
Bio shield cork adhesive - is a water-based elastic glue made from natural latex, plant oils and resins designed for use with cork and carpets. Can be used with sisal, coco, wool and jute backings.
Hendricksen Naturlich Manufacturer's Adhesive
Envirotec Health Guard Adhesive #2027, 2045, 2054, 2055, 2060, 2070, 2080
Envirotec Health Guard seaming tapes #3070, 3080, 3090, 3093, 3094
Alternatives to utilizing adhesives with carpeting include, 3M's Tac Fast system using a loop fabric on the carpet back that engages with hook tape applied to the floor surface (like Velcro). This system eliminates the IAQ issues involved with liquid adhesives. Another mechanical application method is tacking down carpeting on tack strips eliminating the need for large quantities of adhesives.
AFM makes a caulk in it's "SafeCoat" line which is a non-toxic, water-based, elastic emulsion type caulking compound designed to replace oil caulk and putty. It will not dry out or crack and does not release any solvents or obnoxious odors. SafeCoat caulking compound provides a water resistant, flexible, easy to install, non-sag sealant with excellent initial and permanent adhesion. This caulking compound has properties, which enable the application to be made without stringiness, and yet maintains flexibility and toughness. It mat be applied to a variety of substrates and has high durability. High resin content affords maximum bond strength.
Another caulking option is 100% silicone caulk, or aquarium grade caulk. These caulks are available in either clear or white and can be found at most hardware stores.
For current information regarding the manufacturers and distributors of adhesives, please visit < georgebeeller'sinfo >
Although low-VOC adhesives are at present more expensive to make, the cost is no more than 5% higher than conventional adhesives.
Selecting Healthy Building Materials and Furnishings for Indoor Environments, by Marilyn S. Black, PhD -posted online
Austin Sustainable Building Source book - January 2000 a Program of Austin Energy
Environmental Building News - Carpeting, Indoor Air Quality, and the Environment-Volume 3, No. 6 -- November/December 1994
American Formulating and Manufacturing (AFM) product literature
Prescriptions for a Healthy House, A practical Guide for Architects, Builders and Homeowners - Paula Baker AIA, Erica Elliott, MS and John Banta Santa Fe, NM 1998
Architectural Resource Guide - Architects/Designers/Planners for Social Responsibility edited by David Kibbey, September 1999
GreenSpec, Environmental Building News Product Directory and Guideline
Specifications, Dwight Holmes, Larry Strain, Alex Wilson, Sandra Leibowitz