Sealing may refer to two processes: One is the application of a surface treatment to retard staining and preserve its appearance. The second is the application of specialized sealants to plug up tiny openings that are difficult to shut with other materials such as concrete, drywall, etc. Both of these processes prevent penetration of air, gas, noise, dust, fire, smoke or moisture from one location through a barrier into another.
Different types of sealants:
Acrylic construction sealants are used in both interior and exterior applications. They are used primarily for their low cost and paintability. Acrylic sealers are available in both water and solvent based finishes. These are most commonly used for residential and light commercial finishes.
Countertop sealers can be any number of products, depending on the look and outcome desired. It is very common for countertops to use a water based acrylic or a densifier to leave the natural stone finish of the concrete apparent. Maintenance is often done with a carnauba or beeswax polish.
Hardeners and densifiers are penetrating sealers that are absorbed into the pores of the concrete and then crystallize on a microscopic level when dry. The crystalline growths help to seal and harden the surface of the concrete, making it stain resistant and more dense and durable on the surface.
Urethane construction sealants have excellent adhesion to a variety of substrates and have good movement capability. They cure to a soft, flexible but durable rubber. They are used to seal vertical and perimeter expansion joints on buildings and horizontal joints in parking garages and sidewalks. The main disadvantage of urethane sealants is their lack of resistance to UV.
Silicone construction sealants are used mainly in exterior applications. Silicones are virtually unaffected by UV and are becoming the sealant of choice because of their long service life (greater than 20 years). The disadvantages of silicone sealants are the higher cost and limited number of standard colors.
Natural stone is used in kitchens, floors, walls, bathrooms, dining rooms, around swimming pools, building foyers, public areas and facades. Examples of natural stone are granite, basalt, marble, limestone, travertine, sandstone and slate.
However, all natural stone are porous, and this porosity acts like a hard sponge that, over time, sucks in liquids along with dissolved salts and other minerals. If unsealed, the stone will be prone to certain types of damage such as staining, cracking, efflorescence, spalling and acid attacks.
The longevity and usefulness of stone can be extended if it is effectively sealed against damaging liquids and minerals such as salts. The ancient Romans often used olive oil to seal their stone, which provides some protection but stains the stone permanently. During the renaissance, Europeans experimented with the use of topical varnishes and sealers made from ingredients such as egg white, natural resins and silica.
Modern stone sealers:
- Topical sealers made from polyurethanes or acrylics may be effective at stopping stains but, being exposed on the surface of the material, they tend to wear out relatively quickly, especially on high-traffic areas of flooring. This type of sealer will significantly change the look and slip resistance of the surface, especially when it is wet. They do not allow the escape of water vapor and other gases from stone, and are not effective against efflorescence and spalling.
- Penetrating sealers use siliconates, fluoropolymers and siloxanes to repel moisture or liquids. These sealers penetrate the surface of the stone enough to anchor the material to the surface. They are generally longer lasting than topical sealers and often do not substantially alter the look of the stone. These sealers are breathable to a certain degree, but do not penetrate deeply enough to be effective against salt attack.
- Impregnating sealers use silanes or modified silanes, which penetrate deeply into the material, impregnating it with molecules which bond to the capillary pores and repels water and oils from within the material.
For more answers to your questions about sealing, contact Freedom Restoration at 410-451-7110 or click here.