Bostik - Boscoseal PUW - Water-based Modified Polyurethane Waterproofing Membrane

RM 350.00
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Boscoseal PUW is one component water-based modified polyurethane liquid applied waterproofing membrane. After curing it provides a tough, highly elastomeric, impervious barrier to moisutre. Suitable for application by brush, roller or trowel.

  • Water-based
  • One component, No mixing
  • Early access for following trades
  • Brush, roller or trowel applied
  • Does not brittle with age
  • Exhibits tenacious adhesion to masonry
  • Non re-emulsifying
  • Masonry walls, foundations and basements
  • Roof lap slabs, balconies and court yard
  • Beneath terrazzo, paving and quarry tiles
  • Bathrooms, laundries and wet areas priort o tiling
  • Planterboxes

All surfaces must be clean, dry, free of voids, curing compounds, loose materials, oil, grease, sealers and determined to be structurally sound before application of Boscoseal PU. New concrete must have cured for 28 days.

Cracks and other defects must be repaired. Seal all cracks or joints of 2mm in width with Bostik Ultraseal Fillet and Seal before waterproofing application.

Boscoseal PUW can be applied immediately over Ultraseal Fillet and Seal after initial set of approximately 45 minutes at 25°C.


Boscoseal PUW does not required priming on clean and dry substrates but neccesary for areas of infiltration. Dilute a portion of Boscoseal PUW with 2 portion of clean water as primer. Allow primer to cure for approximate 30 minutes.


Boscoseal PUW does not require any mixing. Stir product to an even smooth consistency before use.


Boscoseal PUW can be appllied by brush, roller, trowel or squeegee.

Boscoseal PUW should be applied to achieve a dry film thickness of minimum 1mm for optimum performance. To achieve this dry film thickness, apply Boscoseal PUW at 1 kg per m2.per layer x 2 layers. Minimum 2 layers application needed.

Extremely porous surfaces should be filled prior to application. Apply Boscoseal PUW evenly to avoid thin spots, air entrapment or pin holes. Any defects can be repaired by over coating with Boscoseal PUW.

For applications where two layers of Boscoseal PUW are required, allow 8 hours between layers.

Protection boards must be used to protect the membrane before back filling or concreting. If Boscoseal PUW is damaged, repair by cleaning the surface and recoat with another layer of Boscoseal PUW.

  • Boscoseal PUW should not be applied on wet, contaminated or friable substrate.
  • Rate of membrane cure will be inhibited when air or substrate temperatures are below 5°C.
  • Should not be applied greater than 3kg per m2 in one application as the likelihood of foaming may occur.
  • Requires atmospheric moisture to fully cure. It should not be used on totally confined or air free spaces.
  • Mortar bed screed or tiling should not be carried out until membrane is fully cured.
  • To eliminate possible surface contamination, tiling work should be carried out as soon as possible after curing or following trade protection may be required.
  • Bostik Boscoseal PUW membrane should never be used as an exposed finish or as top coating exterior membrane.
  • Any intention use of Boscoseal PUW out of recommended uses, should refer to Bostik technical services for approval.
  • Not suitable to apply on any form of lightweight concrete.

Technical Data Sheet

20 kg