BETEC™ Flex S150

Two-component, flexible, cementitious coating for waterproofing/damp-proofing of new and existing structures

Product Description

BETEC™  Flex S150 is a flexible, two-part, polymer-modified cementitious waterproofing system. The two components of BETEC Flex S150 are mixed together with a slow speed drill and paddle to form a smooth slurry. The slurry is applied by trowel or brush, in two coats, to form a hard but flexible waterproof cementitious coating.

BETEC Flex S150 is a non-exposed system that can be applied onto damp non-moving substrates, internal and external wet areas. The cured membrane is flexible, durable and has good adhesion to most substrates.


  • Non-chlorinated Swimming Pool (unless the membrane is protected by chlorine-resistant protection screed as well as chlorine-resistant tiles adhesive)
  • Bathroom, balcony, wet area and planter box
  • Non-chlorinated water-retaining structure

Product Advantages

  • Flexible - bridge hair line cracks
  • Good adhesion to concrete, masonry, ceramics, and most common substrates and does not attack metal
  • Non-toxic
  • Direct plaster or screed without affecting bond

Typical Properties

Tensile Strength ≥ 1.8N / mm2 ASTM D412
Elongation ≥ 200% ASTM D412
Adhesion to Concrete ≥ 1.2N / mm2 ASTM D4541
Crack Bridging Capability up to 2mm Pass ASTM C836
No Crack after 10 Cycle of Stretching
and Closing at 1mm Width
Pass ASTM C836

Typical test values represent average values from samples tested in recommended conditions. Refer to Technical Letter 1 for more information.


Pack Size 42kg set
Powder Component 25kg
Liquid Component 17kg
Shelf Life 12 months storage in dry condition


All tools and equipment should be cleaned immediately with clean water after use. Hardened material can only be removed mechanically.


Surface Preparation

  • Chase out all holes and voids and fill with appropriate Mortar from GCP Applied Technologies to provide a smooth and level surface; mortar joints should be flush pointed.
  • The substrate shall be sound and stable with zero substrate movement. Do not apply cementitious over joints or non-core filled reinforced blockwork. 
  • Remove all bitumen, oil, grease, dirt and other surface contaminants by wire brushing and pressure washing. Cut back any protrusions.


  • Shake the liquid well and pour around 75% into a clean mixing container.
  • Slowly add the BETEC Flex S150 Powder while mixing.
  • Mix until a homogenous slurry, free from all lumps, is formed.
  • Scrape any unmixed material from the side of the mixing container with a trowel and mix in.
  • Finally, add the appropriate amount of the remaining liquid to achieve the required consistency for application.
  • It is recommended that mechanical mixing (400 to 500rpm) should be used for 2 to 3 mins to ensure proper dispersion of the components.
  • Pre-wet the surface with clean water. Do not allow pooling or ponding.
  • Apply the first coat of BETEC Flex S150 mixed materials onto the prepared surface using a brush, trowel, squeegee or roller in a stifling action.
  • Apply the second coat finish depending on site conditions and film thickness required.
  • Before applying the second coat in alternate direction, leave the first coat to dry for approximately 2 to 4 hours depending on the thickness.
  • If overcoating is done more than 24 hours after applying the previous coat, or the previous coat has already dried out, the surface must be pre-wetted again.

Coat Thickness and Consumption

  • Total minimum dry-film thickness 1.2mm
  • Minimum 2 coats for internal wet areas
  • Minimum 3 coats for non-chlorinated water retaining structures
  • Minimum consumption 2Kg/m2

(Number of coats and consumption is dependent on the substrate porosity)

Technical Services

For assistance with working drawings for projects and additional technical advice, please contact GCP Applied Technologies.

Health and Safety

BETEC Flex S150 is classified as non-hazardous. Read the product label and Material Safety Data Sheet before use. Protect hands with rubber gloves. Avoid contact with eye and skin. In case of contact, wash immediately and thoroughly with water and seek medical advice. | Thailand customer service: 66 2 030 9700

We hope the information here will be helpful. It is based on data and knowledge considered to be true and accurate, and is offered for consideration, investigation and verification by the user, but we do not warrant the results to be obtained. Please read all statements, recommendations, and suggestions in conjunction with our conditions of sale, which apply to all goods supplied by us. No statement, recommendation, or suggestion is intended for any use that would infringe any patent, copyright, or other third party right.

BETEC is a trademark, which may be registered in the United States and/or other countries, of GCP Applied Technologies, Inc. This trademark list has been compiled using available published information as of the publication date and may not accurately reflect current trademark ownership or status.

© Copyright 2021 GCP Applied Technologies, Inc. All rights reserved.

GCP Applied Technologies Inc., 2325 Lakeview Parkway, Alpharetta, GA 30009, USA
GCP Applied Technologies Holdings (Thailand) Limited., 848 Moo 2, Bangpoo Industrial Estate (North), Phraksa Mai, Muang Samutprakarn, Samutprakarn 10280, Thailand
This document is only current as of the last updated date stated below and is valid only for use in Thailand. It is important that you always refer to the currently available information at the URL below to provide the most current product information at the time of use. Additional literature such as Contractor Manuals, Technical Bulletins, Detail Drawings and detailing recommendations and other relevant documents are also available on Information found on other websites must not be relied upon, as they may not be up-to-date or applicable to the conditions in your location and we do not accept any responsibility for their content. If there are any conflicts or if you need more information, please contact GCP Customer Service.

Last Updated: 2023-07-07