Why Water-Repellents are Important

Concrete and masonry surfaces are porous and absorb water to varying degrees. As water enters the surface it sets up conditions that can result in a variety of problems:

• Deterioration of the surface caused by freeze-thaw and efflorescence
• Loss of structural strength caused by rusting of rebar, nails and fasteners
• Mold and mildew growth in interior wall cavities
  (because moisture is an essential requirement for the growth of mold and mildew, by helping keep areas prone to mildew growth dry, water repellents help prevent mold and mildew growth.)
• Damage to interior drywall, carpeting and flooring

Water-Repellent Sealers provide protection without changing the texture or hiding the underlying substrate of the following materials:

How to determine if a building has been sealed with a water repellent.

• Masonry walls that leak create problems for contractors, architects, maintenance supervisors and building owners.
• Water that passes through exterior walls can damage interior wall finishes, floor coverings, ceilings and building contents.
• Water that penetrates only the exterior face can cause staining, corrosion, efflorescence, and freeze-thaw spalling.
• The water penetration test can demonstrate the performance of new concrete and masonry or assess the condition of existing concrete and masonry.

Three commonly used methods of measuring water penetration in masonry are:

• ASTM E514, Test Method for Water Penetration and Leakage through Masonry
• Navy Hose Test
• Low Pressure Tube Test or the Rilem Tube Test. This test simulates a 95 to 49 mph wind driven rain depending on the amount of water
  remaining in the vertical section of the tube at the end of the defined period of time. This is the easiest and simplest test to perform

How to do a RILEM Tube Test---

1. Select test locations around the building including the block and the joints.
2. Attach the special Rilem Tube that is part of your inspection kit supplied by your Zinsser sales rep, to the concrete surface test locations.
3. To attach the tube, take the putty supplied and roll it into a snakelike piece approximately ¼” diameter and 6” length to fit around the brim of the tube.
4. Firmly press the tube with the attached putty to the surface forming a watertight seal between the tube and the masonry.
5. Fill the tube with water. The tube which holds 5 milliliters of water is graduated in .1 milliliters increments from 0 to 5 ml.
6. If the water starts to immediately fall from the tube and soak into the building, this building is a candidate for a water protective sealer.
7. If the tube holds the water for 3 minutes, it means an uncoated block is very dense. A coated block that looses no water in this time has excellent protection.
8. Use the chart here to determine the amount of water loss and porosity of surface.

Record the type of surface, surface texture, test location, and amount and time period of water loss and, if any.