When selected and applied with care, clear water repellents can help reduce moisture penetration in masonry, thereby minimizing efflorescence, freeze-thaw damage, joint and cavity steel corrosion, mildew, and loss of insulation value. With more than 500 clear water repellents on the market, do a lot of shopping and ask questions before selecting a product.

Water Repellent Properties
There are five main categories of water repellents: acrylics, silicones, silanes, siloxanes, and blends (usually a combination of silane and siloxane). Each has unique properties and price ranges.

Analyze Your Needs
Before selecting a water repellent, analyze all your needs. Consider the condition of the substrate and the requirements of the job.Product Evaluation
When evaluating clear water repellents, be sure to read the manufacturer's literature thoroughly.

Test Product Samples
Most manufacturers will recommend the types of substrate for which each product is suited. Make sure that test information is available for your project's substrates. From this data, select about five water repellents for testing.

Surface Preparation
No water repellent is good enough to overcome the effect of a poor application. Don't spend time and money choosing and buying the best product if you're not willing to follow the manufacturer's application instructions.

Applying the Product
Once surface preparation is complete, it's time to apply the product. Coverage rates vary from about 125 to 200 square feet per gallon for clay brick walls to about 75 to 125 square feet per gallon for concrete block walls.