Masonry Magazine November 2003 Page. 31
Silicone Rubber
UNLIKE THE SILANES and siloxanes, repellants manufactured using room temperature vulcanizing (RTV) silicone rubber react with porous substrates without the requirement for alkali to be present; therefore, they can seal any porous building material including natural stone.
The silicone rubber, used in this class of repellants, has been refined to the point of being inorganic. Ultraviolet rays, acid rain, salt spray or airborne pollutants do not break it down. This provides for long lasting protection.
"It's still working on vertical surfaces, that we know of, that were treated 16 or 17 years ago," says Hall. "To say that it's never going to break down, I can't tell you that. We have data indicating that the raw material (silicone rubber) has been evaluated in actual use, in all climates, showing no deterioration after 30 years.
Additionally, in the cured state, silicone rubber repellants retain the 400% elasticity of the raw material. This enables the bridging of minor structural defects such as hairline cracks, eliminating the need to repoint or caulk every minor flaw.
"In new construction, assuming that the flashing, weeps and damp-proofing are properly installed, it may seem that application of a water repellant is unnecessary, however it should be considered as the final step in completing the building envelope," says Hall. "You're adding one more element of protection and protecting the structure for the long-term."
Strength in Numbers
PROFESSIONAL PRODUCTS of Kansas, Inc. manufactures an RTV silicone rubber sealant (Professional Water Sealant) that is available in three strengths which compensate for varying porosities of building materials. These products can effectively seal even the most porous substrates with only one coat provided that the strength appropriate to the porosity of the substrate is used.
"One application will provide protection for over ten years," adds Hall. "That's what we guarantee."
Graffiti Protection
Professional Water Sealant is also used as an effective, non-sacrificial barrier against graffiti. Unlike waterproofing, graffiti protection requires a two-coat application.
Once the sealant has been applied it allows for the easy removal of graffiti. Treated surfaces can withstand repeated cycles of tagging and removal with no requirement to reapply the sealant.
Ken Barry is active in the construction industry. He has been involved with associations such as: National Paint and Coatings Association, Construction Specifications Institute, American Institute of Architects, Brick Institute of America, International Parking Institute and the Sealant, Waterproofing and Restoration Institute. He is also an active speaker and presenter throughout the country. He can be reached at (316) 522-9300.
With waterproofing sealants, you're adding one more element of protection and protecting the structure for the long-term.
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