FREE Ground Shipping on orders over $50 (Lower 48 only)

Negative Pressure Waterproofer

0 out of 5 based on 0 customer ratings
(0 customer reviews)

SEAL-ONCE’s Negative Pressure Waterproofer (NPW) reacts with free alkali in concrete materials forming a silica hydrogel that fills the capillaries within the structure of the material. This hydrogel seals and waterproofs the surface once harmful materials have been purged.

NPW can be used below grade in basements, parking structures and foundations.

  • Blocks or reduces water vapor emissions and the migration of radon gas
  • Penetrates the material using nanotechnology
  • Allows for a breathable barrier
  • Resistant to many acids, oils, greases and salts
  • Halts corrosion and oxidation of reinforcing steel in concrete from salt air and humidity

Recommended Use: Concrete Block Precast Mortar Stone Basements Parking Garages Foundations




Product Details

  • Eco-friendly
  • Ultra-low VOCs
  • Water based
  • Non-toxic; will not harm pets or plants
  • Breathable barrier
  • Non-flammable
  • Non-combustible
  • Non-acid sealer
  • All surfaces should be cleaned before sealing for best penetration and performance.
  • Clean all dust, debris and loose material. Remove oil, grease, algae, grime and mold and mildew stains with appropriate cleaners. Recommend SEAL-ONCE Concrete/Masonry Cleaner
  • Test absorbency after cleaning by sprinkling water on surface. If the water does not readily penetrate the surface, stripping will be necessary to remove old coatings.
  • Ensure surface is free of dirt, debris, oils, grease, old adhesives, coatings and standing water
  • Shake or mix container well before using
  • Do not dilute or alter the material in any way
  • Apply NPW with a low-pressure pump type sprayer using a fan tip
  • For Horizontal Surfaces
    • Apply in a left-to-right motion, overlapping spray pattern by 50%
    • After first application soaks in, immediately apply a second application in an up-and-down motion, overlapping spray pattern by 50%
    • Avoid over-application or ponding
    • Excess un-reacted product will leave white crystals on the surface. Sweep or brush excess to dry areas
  • For Vertical Surfaces
    • Apply from top-to-bottom to the point of refusal
    • Apply sealer in two even coats
    • Apply second coat immediately after first coat has soaked in

Clean Up:
Rinse equipment with cold water. Do not leave behind any empty containers. Dispose of containers appropriately

Maintenance & Care:
WARNING: NPW should never be used on tile. CAN ETCH GLASS. Remove immediately. Do not dilute or alter. Protect from freezing. Protect vehicles, glass surfaces, plant life, aluminum, ceramics, glazed tile and wood from overspray. Remove overspray with soap and/or water immediately. Unprotected areas should be pre-wet with water and rinsed continuously. Eye protection, gloves and appropriate clothing should be worn to minimize skin contact.

$5 Off Your 1st Order.

Sign Up to be a SEAL-ONCE insider and get early access to special offers & new products.