A. General application procedures, including for low moisture content and low hydrostatic pressure :
Surface Conditions

Virobond 505 can be applied to dry surfaces, but is best applied to cool, damp surfaces as it will penetrate deeper. Always ensure there is no standing or running water on the surface be treated.
Be aware of surface temperature. If the concrete or substrate is too warm, (l.e. warm to the touch), evaporation will reduce the amount of Virobond 505 available to penetrate through the slab. To ensure a minimum of product lost to evaporation, pre-wet or soak the area to be treated with water, spread out or mop up any puddles, and proceed with the Virobond 505 application when the surface has dried to the “dump” stage.


Apply Virobond 505 liberally (at minimum the predetermined coverage rate) and saturate all areas. Each spray swath should over lap the previous one by half it’s width. To ensure saturation, check areas 15 to 20 minutes after application and reapply to those areas where the Virobond 505 is being absorbed most quickly. Now wait one hour before repeating a second application. The recommended procedure is apply Virobond 505 until the concrete is wet and shiney, reapplying 15 minutes later to those areas that are most absorbent and drying fastest, an hour later repeat with a second application.

Do not leave puddles of Virobond 505 on surfaces. Use a mop or squeegee to spread or remove any puddles. Applying water over a Virobond 505 application will push the Virobond 505 a bit deeper. It is recommended the water be applied no sooner than when the surface treated with the Virobond 505 is no longer wet, but, not yet dry. l.e. Damp.

Easy ASTM 4263 “Sponge” Test for Determining excess Moisture Vapour Transmission
Three to four days after the first application of Virobond 505, the treated surface should be thoroughly flushed with clean water, to remove any alkali or contaminants the Virobond 505 has pushed to the surface. Allow surface to dry.

To determine whether a second application of Virobond 505 is necessary; Tape down several 12″ pieces of ordinary poly, sponge or foam rubber, to the sry slab. Leave for 24 hours, then remove. If, the slab beneath or the poly etc., Itself, is wet, there is still excessive moisture vapour transmission, which means the concrete is not yet sealed.

The Virobond 505 for this second application should be applied to saturation again, checking for areas of varying porosity, and re-applying, but, not leaving any puddles. Wait a minimum three to four days for the Virobond 505 to cure. Any alkali or leaching which occurs after the second treatment must be flushed off and the slab cleaned thoroughly (and allowed to dry) prior to a re-testing with poly or sponges to determine the need for any further application of Virobond 505 If a third coat is necessary, dilute the Virobond 505 1:2 with clean water.

Note : Good examples of substrates with extraordinary contaminant content would be steps, sidewalks, driveways, etc., which have been salted over many years. In such cases the same process of flushing the Virobond 505 treated surface (min. 3 to 4 days after applying Virobond 505) which ensures all salts, or contaminants which Virobond 505 has pushed to the surface are removed, could still push the Virobond 505 deeper, pushing more contaminants to the surface. In extreme cases, cycle of daily flushing and drying for up to 3 to 7 days could be necessary before no further contaminant appears after drying.

Once the rinsing is no longer flushing anything to the surface, you’ve had a successful sponge test, and no further application of Virobond 505 is required, the treated and flushed surface should be allowed to thoroughly dry for a minimum 24 hours prior to the application of any secondary coatings.

On vertical formed surfaces; Apply Virobond 505 as soon as the forms have been stripped and the surface rubbed, (if required). Apply from the bottom up, going over the area twice to ensure saturation. One such application (to saturation) will usually be sufficient for most requirements. Back-filling foundations may take place 12 hours after application.

Foot traffic is permissible in most cases within 3 hours or when surface appears dry. On overhead surface, Virobond 505 is best applied with a sprayer using multiple light applications as required. The first application should wet the surface. Do not saturate as dripping will occur.

B. Applying Virobond 505 over a Patch or Overlay done with polymer based topping mixes.
Follow the same surface preparation and Virobond 505 application steps and procedures as in Section A above. However, to ensure adequate saturation, always assume a minimum coverage rate of 5.0 sq. meters per litre for Virobond 505 applications over a fully cured (min. 48 hours) patch or overlay. Virobond 505 will not, because of the polymers in such mixes, penetrate as deep as it would if applied to a non-polymerized, alkaline substrate, but, it will increase surface hardness, dust-proofing and water-proofing performance and the bonding of any subsequent coatings applied to the new surface.

Coverage Rate
Every substrate to be treated will have a different and specific absorbency, and even the absorbency from spot to spot on the wall/slab/etc., will vary. Because of this, it is essential, prior to the application, to carry out a small scale test on part of the area to be treated, in order to predetermine as best as possible, the coverage rate specific to the particular substrate to be treated in each case. Coverage rates with Virobond 505 can range from a max. 6.0 sq. metres / litre (225 sq. feet / US gal.) down to 1.0 sq metre per litre or less if used for curing. Average coverage is 4 sq. Metre / litre (150 sq. feet / US gal.)

Coverage rates are directly proportionate to the porosity and moisture content of the surface being treated and will get lower as the substrate being treated with Virobond 505 gets more porous or as the moisture content increases. Example of coverage :

  • Fully cured, concrete floors float finished with a high surface tension and low moisture content can be up to 6.0 sq. Meters per litre.

  • Substrates overlaid with patching or topping mixes or concrete newly stripped of its forms, will be approx. 5.0 sq. Meters per litre, or less.

  • Used as a curing content, or in extreme repair applications where the high water content will dilute the Virobond 505 coverage can range from 4.0 sq. Meter to 1.0 sq. Meter per litre, or less.