Most experts agree that there is no single correct approach to the selection of appropriate clear water repellent treatments for concrete masonry. However, there has been a great deal of research on the subject to help contractors make an informed decision.

A practical source of information on this topic is Clear Water Repellent Treatments for Concrete Masonry. This 62-page book was authored by John Raeber and published by the Masonry Institute of America and the Concrete Masonry Association of California and Nevada.

For most projects, Raeber suggests that sealant product literature and local manufacturer representatives are the key sources of information regarding the application. Hopefully, manufacturer reps are the first to realize the danger to the company's reputation if its products prove unsuitable for a specific application.

Raeber offers 10 questions that help provide the contractor a uniform approach to compare various products.

1. What are the manufacturer's recommended applications?

The natural porosity of concrete masonry may be inappropriate for some forms of water repellent treatments.

2. Is the product intended to be a surface film or penetrating sealer?

Most products are formulated as one or the other, but when not clearly identified it is probably a surface sealer.

3. How many coats are recommended?

Check the appropriate number, coverage rate in square feet per gallon, and timing between coats.