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Okon W-2 is a water repellent sealer for porous concrete and masonry, sold here in the 1 gallon size (Okon OK-921). It combines acrylic micro emulsions with a silane-siloxane solution that penetrates and forms a water-repelling barrier below the surface, while staying highly permeable to water vapor. Rust-Oleum says it helps protect porous block, stucco and brick from water absorption, efflorescence, freeze-thaw damage, dusting and staining.
Free shipping at $75, no code needed (lower 48 + DC). Free 30-day returns with a prepaid label. Returned items must be unused and unopened; opened paint, aerosols and flammable liquids can't be returned (refund policy).
| Resin | Acrylic / silane-siloxane, water-based |
|---|---|
| Color | Colorless; goes on milky white and dries clear |
| VOC | Under 70 g/L |
| Apply at | 50-100 F, under 85% relative humidity |
| Estimating coverage | Varies with porosity and texture, for example about 65 sq ft per gallon on smooth medium weight CMU and 80 on smooth normal weight CMU. A test area sets the actual rate. |
| Dry times (70-80 F, 50% RH) | Recoat 3 hours, foot traffic 8 hours, heavy traffic 24 hours; protect from rain 24 hours and dew 12 hours |
| Water vapor transmission | 11.82 perms (ASTM E96) |
| Shelf life | 3 years; keep from freezing |
| Manufacturer part # | OK921 |
Limits: W-2 does not protect against hydrostatic water pressure, will not bridge cracks or fill large pores, and cracks and joints must be sealed with a flexible sealant first.
Which surfaces is W-2 for? Rust-Oleum recommends it for porous surfaces including medium and normal weight CMU, rough stucco, porous plaster, blasted concrete and concrete brick. Do not use it on glazed or non-porous surfaces.
How do I know if one coat is enough? After application, water should bead and sheet off the surface. If it does not, Rust-Oleum says to apply an additional coat once the first is dry, clear and colorless.
Can I paint over it? Rust-Oleum lists it as paintable, but says it may interfere with paint adhesion on denser substrates like cast concrete. If you plan to paint within six months, do a test area first.
Sources: Okon W-2 technical data sheet OKN-04; Rust-Oleum Okon W-2 page. More prep and patch supplies.
Free standard shipping on orders $75+ to the lower 48 states and DC. Some large or heavy items are excluded at checkout.
30-day returns on unused, unopened items. Returns accepted within 30 days. We send you a prepaid return label. Contact us within 30 days of delivery to start a return. Opened paint, aerosols, flammables, special orders and sale items can't be returned. Read the full refund policy.
Use this product page for the exact item, then check the Weekend Project Carts for prep, applicators, patch, cleanup, and finishing supplies. If you are still choosing a method, start with the Project Guides before adding everything to cart.
