Sealants
This article is courtesy of Healthy Home DesignsWhat are they?
Sealants are used as a finishing step for a majority of building materials. Often they are used as a protective coating to prevent water, dirt or abrasion resistance. Both sealants and paints cover many of the largest surface areas of any new construction- giving pause to the products used for this purpose. Sealants, sometimes referred to as stains are also available in colors, making them a finishing choice.
For our purpose, although paint is a sealant we will be talking about sealants other than paint. (see Paint Fact Sheet, for information on healthy paint)
Sealants often introduce toxins to a site that negatively affect indoor and outdoor air quality. The best way to avoid the issue of a potential negative impact on indoor air is by employing materials and surfaces which do not require additional coatings, such as raw plaster, stucco, natural stone, ceramic tile or glass. However, many of the materials that we find attractive, warm toned and comfortable, such as a nice hardwood floor, require a sealant to prolong its life in our homes.
Thankfully, today there are numerous products to choose from, providing a safe, healthy alternative to the old standard. Several natural stains manufactured entirely from plant chemistry and non toxic by-products are now imported from European sources and readily available here in the Bay Area.
Uses
Sealants can be used for floors, cabinetry and furniture, decking, exterior siding and many other uses. Stains can be used as a finish for interior wood such as furniture and can be used without an additional protective sealer where high traffic or abrasion is not an issue. The porous breathing nature of this type of coating allows the cellular structure of natural wood, stone clay and plaster to interact with temperature and humidity, much like the human skin does. However, most materials benefit most from a sealant that provides both aesthetic properties and protective ones. Some products provide both of these attributes.
Attributes
Health
Conventional sealants are commonly based on petroleum solvents and should be avoided in both interior and exterior applications whenever possible. Petroleum solvent based oil stains contain large amounts of unstable hydrocarbons and other toxic chemicals which volatilize into the air at room temperature. Vapors are most potent at the time of application, but most petroleum-based products require up to a year to fully oxidize, cure and become stable. Some have been known to remain active for several years. Although water reducible paints and finishes do not have volatile thinners they may still contain petroleum distillates, VOC's and other potentially harmful additives. Additives are used to give the product various qualities: dryers, hardeners, surfactants, anti-foaming agents, emulsifiers, heavy metals, biocides and fungicides. These are strong candidates for introducing more VOC's into the air, especially on a short-term basis.
The use of the following sealants should be avoided indoors: butyl rubber, solvent based acrylic, and neoprene. Do not use any products containing methylene chloride or chlorinated hydrocarbons.
Select low-toxic, non-toxic, or plant-based products for sealing exposed materials. We have provided a list of manufacturers for you, listed by the applications, below.
Environmental
Solvent-based adhesives should be treated as hazardous waste and disposed of accordingly. The manufacturing process of these products is also of concern to the environement
Functional Characteristics
Installation
Surface Preparation -All surfaces must be cleaned of any grease, oils, dust, dirt, wax, old adhesives and other foreign materials. Washing with a nontoxic cleaner or TSP is recommended. The surface must be completely dry prior to application. When applying - always have adequate ventilation.
Minimize the use of sealants through proper detailing, including adequate overhangs and eaves, flashing, and proper lapping of building paper and trim. (GreenSpec pg.130)
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?
INTERIOR WOOD SEALANTS (Floors, cabinetry, shelving, furniture etc.)
Safecoat DuroStain - by AFM enhances wood with a choice of seven wood toned pigments and is suitable for applications from high quality furniture to wood siding . DuroStain contains no coal tar, aniline dyestuffs, waxes or aromatic solvents. It is fast drying, semi-transparent flat finish wood stain for both interior and exterior surfaces. Water-based for easy clean-up DuroStain provides good penetration, excellent sealing properties and long term pigment stability and is sufficient for areas that are not subject to abrasion (Note: where abraision resitance is required surfaces should be coated with a hard clear finish.)
Safecoat Acrylacq - by AFM is a clear, high gloss, water based replacement for high solvent content lacquer. It is hard and durable with resistance to stains, marring and fingerprints. Safecoat Acrylacq cures with out emitting toxic fumes and can be used for wood, high quality furniture, galvanized or primed metal and other plastic surfaces.
Safecoat AcriGlaze - by AFM…
EXTERIOR WOOD SEALANTS (decking, shingles, siding etc.)
Safecoat DuroStain - by AFM enhances wood with a choice of seven wood toned pigments and is suitable for applications from high quality furniture to wood siding . DuroStain contains no coal tar, aniline dyestuffs, waxes or aromatic solvents. It is fast drying, semi-transparent flat finish wood stain for both interior and exterior surfaces. Water-based for easy clean-up DuroStain provides good penetration, excellent sealing properties and long term pigment stability and is sufficient for areas that are not subject to abrasion (Note: where abraision resitance is required surfaces should be coated with a hard clear finish.)
Crystal Sheild - by…
POROUS SURFACE SEALANTS (cement, tile & tile grout, )
MexiSeal - by AFM is a low odor, non-toxic, sealant designed for hard composition wall and…..
WATERPROOFING (for roofs, foundations and other wet applications)
DynoSeal - by AFM, www.afmsafecoat.com is an asphaltic emulsion waterproof sealer with a VOC content of less that 100 g/l for use on roofs and foundations and driveways.
Rub-R-Wall Foundation waterproofing - by Rubber Polymer Corp. is made of synthetic rubber and is applied under high pressure and temperature by professionals. Rub-R-Wall has a lifetime limited warranty.
Xypex Concentrate - by Xypex Chemical Corporation, www.xypex.com sounds scary, but is a cement-based slurry with non-toxic ingredit=ents that penetrate the pores of concrete and masonly, producing a watertight coating. This product is even approved foir use on potable water structures and contains no VOC's
JOINT SEALANTS
SafeCoat Dynoflex Natural Tan - by AFM is a water based, low odor elastomeric sealer that comes in a paste like compound for sealing joints, seams and cracks in air conditioning and heating ducts and for repairing metal roofs and asphalt shingles. Also comes in a sprayable form that can be used as a topcoat for roofs and decks.
CARPET SEALANTS
Carpet Seal - by AFM is low odor, non-toxic, water based sealant…
Cost Factors
Low-VOC sealants are currently comparable in price to conventional.
References
Austin Sustainable Building Source book - January 2000 a Program of Austin Energy
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
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