June 05, 2024

Using Pecora Architectural Silicone Sealants on Precast Concrete


Precast concrete construction products have been in use for many years and are continuing to grow in use in a variety of applications. The use of precast based building façade panels to offset the cost of expensive natural stones is ever increasing as are the methods and formulations utilized in the manufacturing of precast construction components. Because of the wide variety of precast materials available to the design professional, architect, and contractor in today’s construction process Pecora cannot assume that all precast is created equal.

Because of this diversity of materials the utilization of sealant manufacturer resources, in the form of complimentary laboratory and field adhesion testing, has become more important than ever. Pecora offers complimentary testing for any project using Pecora architectural sealants. Please visit the Technical Service page on the website at for information and forms that will be helpful in streamlining a successful application of Pecora architectural sealant products.

Pecora architectural silicone products for use on precast guidelines:

Pecora utilizes several different primer chemistries for obtaining adhesion to problematic construction surfaces. Pecora P-225 primer is required on all precast substrates and is always the first choice unless laboratory testing indicates otherwise. The chart below gives some general guidelines as to the choices available for precast projects for both similar and dissimilar substrate applications. While the majority of sealant applications involve sealing dissimilar materials such as window frames to porous façade materials, we have included guidelines for applications bonding similar materials, such as metal to metal and precast to precast type applications.





Note: Mechanical abrading or diamond grinding is always an option for surface preparation and will contribute to creating a uniform surface for sealant application. The use of a primer may still be necessary even after the grinding procedure has been accomplished. The use of the above guidelines along with adhesion testing is still recommended.

The chart above is a general guideline for primer recommendations and should not be interpreted as accurate for all project conditions. The use of the above recommendations should result in a high performance sealant application but should always be verified by either field or laboratory testing. For further information and sealant application recommendations please contact the Pecora Technical Services at 1-800-523-6688.

¹Primer is not typically required for weather seal applications on non-porous substrates such as anodized aluminum, coated metals, Kynar, PVC, vinyl, etc.


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