Boscoseal 21

Boscoseal 21 is a concrete waterproofing by crystallisation

Concrete waterproofing by crystallisation

Boscoseal 21 is a surface applied material which waterproofs and protects concrete in-depth. It provides a deep seal penetration and permanent protection against fresh and salt water under pressure. It consists of Portland Cement, specially treated quartz sand and a compound of active chemicals.

When Boscoseal 21 is applied to a concrete surface, the active chemicals combine with the free lime and moisture present in the capillary track, to form insoluble crystalline complexes. This is known as crystallisation processs. Once the crystals have been formed, they remain permanent. These crystals block the capillaries and minor shrinkage cracks in the concrete to prevent any further water ingress. However, the layer will still allow the passage of water vapour through the structure (i.e: the concrete will still be able to "breathe").

Further contact with water will reactivate the sealing process. Thus the lower depths of the concrete form an intergral mass with the surface, which cannot be blown off by hydrostatic pressure. In addtion to waterproofing the structure, Boscoseal 21 protects concrete against sea water, waste water, aggressive ground water and certain chemical solutions. 

  • Can withstand up to 30 metres of hydrostatic pressure
  • Can applied both internally or externally
  • Protects concrete and reinforcement against corrosive water borne substances
  • Durable, lasts as long as the concrete
  • Economical and simple to apply

Related Products

Moisture Seal

Epoxy Water Vapour Barrier

View Product

Aquashield BX

Bitumen emulsion waterproofing coating

View Product

Boscocem Slurry

Two-component cementitious waterproofing

View Product


Flexible cementitious waterproofing membrane

View Product


Elastomeric cementitious waterproofing membrane

View Product

Boscoseal 16

Self adhesive sheet waterproofing membrane

View Product

Boscoseal AC2

One part fibre reinforced waterproofing membrane

View Product

Boscoseal Admix

Waterproofing by crystallisation

View Product

Boscoseal AR

Anti-root water-borne liquid applied waterproofing membrane

View Product

Boscoseal PUR

Liquid applied waterproofing membrane

View Product

back to top