Dictionary of Moisture Protection & Restoration

not be painted except when they can be coated with elastomerics of comparable elongation. Silicones: Derivatives of silicon produced by combining silicon, oxygen, and organic materials. Silicones have extremely high thermal stability and are used as abrasives, lubricants, paints, coatings and synthetic rubbers. Silicones are available in a wide range of compositions that are extremely effective in high-movement joints. They have excellent recovery capabilities, usually up to 100%. Silicones have very little shrinkage, 3%, and a tack-free time of only 1 – 3 hours. High-tensile strength silicones with lower movement are typically used in glazing (wet seal) applications. Most silicones come in one-component packaging. They have excellent adhesion to almost all building products if such substrates are properly prepared. They come in a variety of standard or custom colors, as they cannot be painted over, except for siliconized elastomerics. Silicones contaminate all surfaces they encounter, making it virtually impossible to seal over with any other types of sealants. Only abrasive methods can remove silicone residue or primers. Do not use silicones below grade, submerged or for horizontal applications subject to vehicular traffic. The uncured silicone can stain or change the color of the substrates. Pre-formed silicone and polyurethane tapes: These are relatively new technologies in urethane and silicone.

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