Masonry Magazine November 2003 Page. 30
Waterproofing
BELOW-GRADE WATERPROOFING
RTV silicone **rubber** can seal any **porous building** material including natural **stone**.
When applied, silane and siloxane repellants penetrate into the substrate and react chemically with the alkalinity therein to form a resin. The resin that forms has no elastomeric properties and is designed to make the capillaries of the substrate smaller than that of a water molecule. This is what provides the repellency. In order for the chemical reaction to take place, which is necessary for forming and bonding of the resin within the substrate, silica must be present. Therefore, unless a catalyst is added in the manufacturing process, silanes and siloxanes are not effective in sealing substrates such as natural stone or wood.
Silanes have the smallest molecular structure and are typically used on your denser surfaces such as horizontal and poured in place, smooth face concrete. Highly volatile, up to 40 percent of the silane material can be lost to evaporation prior to the reactive forming of the resin. Siloxanes have a slightly larger molecular structure and are somewhat effective on substrates up to medium porosity such as heavyweight, smooth-faced, concrete block. Unlike silanes, their chemical composition does not encourage rapid evaporation. Therefore, their solids content is usually less than that of silanes.
"Silanes are the deepest penetrants and they can penetrate fairly deep into the masonry," says Vicky Hall, Sales and Marketing Director for Professional Products of Kansas. "Siloxanes don't penetrate as deep as silanes, but deeper than the silicone rubber."
Neither silanes nor siloxanes, as a result of their molecular structure, are very effective at sealing your more porous substrates such as lightweight, split-face or expanded shale block.
All foundations will eventually get cracks, typically within the first year. Some coatings stretch over the cracks but become weaker, while others can crack with the foundation leaving your wall prone to headwater pressure. Typical tar coatings may dissipate into the soil in as little as five years due to ground settlement and the alkalis in the soil.
While a coating may seal the foundation, keeping water out, it does not provide for soil drainage and may also trap moisture caused by high indoor humidity and dampness inside the home. This interior moisture can create the perfect environment for mold and mildew growth.
Superseal Dimpled Membrane is a tough 24-mil HDPE (High-Density Polyethylene Membrane). Superseal Dimpled membrane is unrolled against the concrete block foundation with the dimples facing the wall and fastened with Superseal DimpleGrip Molding along the entire top edge, hanging like a curtain. Vertical joins are overlapped and buttoned like a shirt with Superseal Plugs. This creates an air space that keeps the backfill from touching the concrete block foundation while allowing construction or interior moisture to condense on the membrane and fall freely to the drainage tile for removal. Superseal Dimpled Membrane is not a coating so it has no curing time and can be backfilled immediately to provide waterproofing and 6.6 gal/min/ft of drainage in one application. Typical wall cracks do not affect the membrane's performance and it is resistant to alkalis, acids and salts. It also contains 30% HDPE recycled content. The E.P.A. estimates HDPE will take about 300 years to degrade when buried.
Superseal Dimpled Membrane was awarded a CCMC approval, is pending an ICC approval, and meets all U.S. and Canadian standards, ASTM and CGSB requirements.
Only Nature Protects Better.
Professional Water Sealant is a unique, penetrating breathable water repellent for use on all porous, above grade building materials. Manufactured using RTV Silicone Rubber, **PWS** effectively seals even the most porous concrete block and can actually bridge hairline cracks.
With only one coat, **PWS** creates an invisible barrier that prevents damage associated with water absorption. In a two-coat application it provides superior, non-sacrificial protection against all types of graffiti.
**Professional** Water Sealant...the best waterproofing and graffiti protection money can buy.