Crystalline Capillary Waterproofing


Mitchell’s MitchSeal CWP is a cementitious capillary waterproofing system, which provides a permanent solution to leakage, seepage or ingress of water in concrete by sealing capillaries and shrinkage cracks in both positive and negative side of the structure. MitchSeal CWP penetrates into pores of substrate by capillary action and is carried deep into concrete by inherent moisture therein. MitchSeal CWP is activated by moisture and reacts with free lime present in cement matrix and create a continuous barrier of insoluble crystals. The capillaries are permanently blocked to the passage of water. Rate and penetration of crystals depends on presence of moisture, free lime and density of concrete.


MitchSeal CWP is ideal for waterproofing of roofs, retaining walls, basements, water tanks and other water retaining structures, swimming pools, reservoirs, bathrooms, tunnels, machine pits, concrete walls, concrete pipes, canals, dams, elevator pits, sea walls, planters and any other concrete structure requiring protection from water ingress.


Simple mixing and application It is a permanent waterproofing solution as it becomes an integral part of the concrete structures instead of merely being a surface coating or membrane that can be damaged or delaminated. Equally effective for both positive and negative side waterproofing. Will be re-activated upon contact with water thereby providing lifetime protection. Prevents corrosion of steel reinforcement. Does not require special protection during back filling etc.


  • Appearance
  • Pot Life (after mixing with water)
  • Shelf Life
  • Storage Conditions
  • Water Permeability Ted- Cm / sec
  • Control (Untreated)
  • MitchSeal CWP (28 days)    1.8 x 10 -11 21.9 x 10-14 0.5 to 1 Kg/m2 per coat


Ensure that structure is sound and free from dirt, dust, oil, grease, laitance and any other foreign materials which may effect the bond, penetration and overall performance of MitchSeal CWP. In case of very smooth or closed concrete surface, the surface should be mechanically abraded to ensure that the capillary structure is sufficiently open. All large cracks, honeycombs and damaged areas be cut out and repaired with a suitable mortar and allowed to dry prior to application of MitchSeal CWP.
Dampen the surface lightly before applying MitchSeal CWP to facilitate maximum chemical penetration. Add approximately 8 – 10 Ltrs of water to 25 Kgs of MitchSeal CWP, stir the mix thoroughly to form a uniform slurry and apply, in specified quantities, by stiff bristle brush or squeegee. Ensure to prepare only as much amount of slurry as can be applied during its pot time i.e. 30 minutes.
For horizontal surfaces apply in one coat while for vertical surface apply in two coats. Apply second coat when first coat is touch-dry. Light spray of water may be required between coats in hot weather. In extreme hot weather and very low humidity conditions, ensure curing as soon as MitchSeal CWP coating has hardened sufficiently. Water curing should be carried out for atleast 5 days and for as long as possible. The surface may be covered with wet burlap or polyethylene sheets but curing compounds cannot be used.


MitchSeal CWP is available in 25 Kg Bags and 20 Kg Buckets.


For further details and assistance for specific application requirements and for information on other products please contact Mitchell at the addresses given below.