EPI Painting is one of the leading waterproofing companies in Gainesville, FL and Jacksonville, FL. We provide high-quality waterproofing systems to protect your business. Waterproofing protects the surface of your property or structure from water damage, difficult weather, mildew, and other environmental conditions. Our professional team manages different types of sealants and coatings that help prevent premature aging of commercial and industrial buildings.
We work with:
- Liquid-applied waterproofing
- Sheet-applied waterproofing
- Cementitious waterproofing
The use of sealants (caulking) has expanded as façade construction has evolved and new cladding materials have become available.
Typical Applications Requiring Sealants
- Joints between stone veneer, concrete, or metal cladding panels
- Stone to flashing points, masonry expansion, and coping joints
- Joints at window and door perimeters and glass and glazing perimeters
- Joints in horizontal surfaces such as plazas and terraces
While the majority of joints are simple butt joints, special joints developed for new applications include fillet joints, lap joints, glazing beads, and glazing heel beads.
Most high performance sealants used today are silicone or polyurethane-based. However, older buildings may contain polysulfide and acrylic, butyl-, or even drying oil-based compounds.
Selection of a sealant type depends upon the substrate, movement requirements and aesthetics.
Signs Of Sealant Failure
Four general conditions are usually evaluated in assessing sealant failure:
- Adhesion or bond of the sealant to the substrate
- Cohesion or internal integrity of the sealant
Loss of adhesion results in a separation of the sealant from the substrate. This is usually visible in openings along either side of the joint. Loss of cohesion is evidenced by cracking parallel to the joint interface. Loss of elasticity can contribute to adhesive or cohesive failure. This is indicated by the inability of the sealant to recover after deformation, and especially by an increased hardness of the material. Weathering is indicated by chalking, discoloration, random or alligator cracking, wrinkling, erosion, or excessive softening of the sealant surface.
Factors that contribute to these types of failure include improper joint design or improper sealant use. Sealant characteristics for modules of elasticity, elongation, and the expected movement of the substrate must be taken into account in selecting the sealant and designing the proper width of the sealant joint.
Proper selection of the sealant for compatibility to the substrate must be evaluated. If the substrate varies on either side of the joint, different surface preparation may be required for each side.
Improper Sealant Installation
Improper installation of the sealant can also contribute to failure. Sealants are typically installed with polyethylene bond breaker tape, compressible foam backer rod, or other means to prevent adherence of the sealant to the back of the joint. If the sealant is adhered to the back of the joint as well as the sides, it cannot expand or contract without tearing.
If the sealant is installed when the substrate or ambient temperature is too cold (e.g., below 45 degrees F), the joint may be at its widest dimension. The sealant might not be able to accommodate subsequent cyclic expansion of the substrate and compression of the joint upon heating. Low temperatures directly retard the cure of most sealants. Further, if sealants are installed at extremely cold temperatures (e.g., below freezing), frost contamination on the surface will likely interfere with proper bonding.
Conversely, if the sealant is installed when temperatures are too high (e.g., above 90 degrees F), the joint may be at its narrowest dimension, and the sealant may be unable to accommodate cyclic expansion of the joint. If installed at very hot temperatures, the sealant may flow. This is especially likely to occur with dark colored sealants in locations that are exposed to direct sunlight. The durability of some polyurethane sealants can be seriously reduced by high temperature curing.
Types of Sealants
Certain types of sealants cannot bond to other sealants. For example, sealants other than silicone are rarely capable of providing durable bonds to existing silicone. On the other hand, silicones often will not cure properly when installed over isobutylene sealants. It is advisable to avoid installing sealant over an existing sealant, as this usually results in poor geometry for the new sealant joint and limited adhesion to the substrate.
Many sealants cannot bond to often used fluoropolymer-based architectural finishes without the use of a primer. Solvent-based sealant placed over thermoplastic sealants can soften or partially dissolve the sealant, causing partial failure within the paint or at the paint/substrate interface. Where light-colored sealants of any type are applied over neoprene gaskets, the oil in the gasket may stain the sealants. Staining of the adjacent substrate is another significant problem associated with certain sealants.
Urethanes are either one-component (moisture-curing) or two-component materials based on the reaction between isocyanates and hydroxyl components. They are most commonly used to seal porous surfaces in high-movement joints. Urethanes typically have about 25 percent joint movement capability and are commonly used for cladding joints.
Curing at high temperatures (e.g, 120 degrees F) can cause some urethanes to prematurely degrade in ultraviolet light, leading to severe reversion. Under ambient air temperatures of 80 to 90 degrees F, dark-colored substrates exposed to direct sunlight can reach temperatures exceeding 160 degrees F. When some polyurethane sealants are cured at such temperatures, they may appear to have cured normally, but continued exposure to heat and ultraviolet light, may cause them to flow and become bubbled or gummy at lower levels.
One-component urethanes cure by reacting with moisture in the air. Some are made with “moisture scavengers” such as calcium oxide, which serve to inhibit set until placement occurs. If particles of the scavenger are too large and are exposed on the surface, they can react with rainwater and cause stains on window frames and glass.
Problems with multi-component urethanes are usually related to improper mixing. If mixing is incomplete, portions of the sealant will be fluid or uncured. Incomplete curing can also be the result of using materials beyond their shelf life, or under certain circumstances, from improper formulation.
Silicone sealants are based on alternating silicon-oxygen atoms. Most field-applied silicones are one-component products. Some are acetoxy (acid) cured and some are alcohol (neutral) cured. Acid-cure silicones should not be used on acid-sensitive substrates such as limestone, marble, and masonry. Silicone sealants are most commonly used on non-porous surfaces in high-movement joints with capability ranges from -50 to +100 percent. Typical applications include cladding joints where staining is not a concern, and metal and glass substrates.
The most common problem with silicone sealants is staining. Staining is evidenced by dirt accumulation on the sealant itself, or by migration of the sealant plasticizer into the adjacent substrate. Some substrates are particularly vulnerable to migration and staining from silicone sealants. Silicone sealant installed on glazing may adhere poorly if the glass surface is contaminated.
Silicone sealants can fail if water gets behind the sealant in open-cell backer rod. Many silicones do not have good long-term adhesion when continually wet or in standing water. Testing should be done in wet and dry conditions.
Other Types of Sealants
Polysulfide sealants are based on polymers containing sulfur, and typically have a characteristic sulfide odor. Some older polysulfide sealants were plasticized with PCBs that are now considered potentially carcinogenic.
Polysulfide sealants are typically limited to use for cladding joints with potential use for joints in submerged applications.
Acrylic sealants are based on thermoplastic resins formed by polymerization of the esters of acrylic acid. They offer strong adhesion characteristics and limited movement capability. They are typically used for low-movement joints in small-scale construction.
Latex, Styrene, Butadiene, And Acrylic Terpolymers
These types of sealants are based on a colloidal suspension of rubber resin (synthetic or natural) in water. Some are modified with small amounts silicone. Like acrylic compounds, these sealants have limited movement capability and are typically used for low-movement joints in small-scale construction.
Polyisobutylene sealants are non-elastic glazing materials based on petroleum hydrocarbons. They are typically used for glazing joints, splice seals in window frame units, and as the primary seal in insulating glass units.
Coatings and Sealers
Masonry brick and concrete are among the most durable building components available. However, these materials will deteriorate over time if not maintained properly, even in the southern regent’s weather conditions. From our experience, coatings and sealers can be among the most effective methods of protecting brick and concrete structures from the elements.
Advanced Coating Technology
New technology has created penetrating coating compounds to replace the old film forming products for brick and concrete structures. When properly applied, these advanced coatings demonstrate can be very effective in prolonging resistance to weather deterioration.
State-of-the-art clear coatings are based on silicone, silane, and siloxane compounds that penetrate brick and masonry surfaces. Available in gloss or matte finishes, these coatings are intended to provide long-term protection to brick and concrete surfaces.
Today’s pigmented coatings/sealers are based on advanced water-based acrylic or elastomeric materials. Available in a variety of colors, pigmented emulsions penetrate the masonry surface and change the surface to the desired color.
Coatings and Sealers Prevent Water Damage
Sealing brick and concrete walls can prevent water from penetrating junctures exposed to severe weather. Exterior masonry coatings and sealers are considered to be water repellant but not waterproof. Nevertheless, when properly applied, these compounds change the capillary angle of the pores in the face of the brick masonry wall from positive (suction) to negative (repellency). In certain situations, coatings and sealers can also bridge or fill hairline cracks or separations in the face of masonry walls and provide some protection from damaging freeze/thaw cycles.
The amount of surface protection provided for newly placed brick and/or concrete can significantly influence its longevity. Unprotected patches may allow moisture to enter the structure at the patch edges or through shrinkage cracks.
Most coatings can be applied by brush, roller, or spray. Before applying the coating, make sure the wall is clean, as heavy accumulations of atmospheric dirt may interfere with proper penetration or adhesion of the coating and result in poor performance and shorter life. Test the selected coating/sealer on wall sections scheduled for treatment. The test areas should be at least 10 feet square.
Check the moisture content of the wall at several locations and observe climatic conditions to assure consistency with the manufacturer’s recommendation.
Selecting a Coating or Sealer
Select a coating or sealer produced by a well-known manufacturer with strong track record. Request references of similar projects and require test reports for relevant performance criteria and a written warranty from the coating manufacturer.
Verify the qualifications of the application contractor, and make sure the contractor protects adjacent and surrounding surfaces from overspray as necessary.