Sika is the market leader in concrete admixture technology. Combining this with our expertise in waterproofing has led to the development and evolution of the Sika® Watertight Concrete System, now the most widely used system of its type in the UK.

The Sika® Watertight Concrete System provides waterproofing for:

  • Basements
  • Lift pits
  • Retaining walls
  • Concrete façades. As well as for keeping water in, for example: swimming pools

Sika® Watertight Concrete complies with BS 8102:2009 Type B Construction.

The benefits of the Sika® Watertight Concrete System are clear:

  • Available now in powdered (hydrophobic or crystalline) and bulk liquid (hydrophobic)
  • Industry leading design and technical support for complex structures & joints
  • Includes complementary jointing products for a complete watertight seal
  • Incorporates the latest concrete admixture technology
  • No.1 in the UK – all formulas are BBA certified, backed with 15-year Sika® Guarantee

Mix designs

Due to its capillaries and pores, concrete is a naturally-porous material. The Sika® Watertight Concrete System incorporates a range of admixtures to improve its resistance to infiltration:

  • Sika® WT-100 watertight concrete powder – a combined water-resisting and HRWR/Superplasticiser admixture
  • Sika® WT-200 P – a combined crystalline waterproofing concrete and HRWR/Superplasticiser admixture
  • Sika® 1+ – a liquid water-resisting waterproofing admixture

The system also creates the optimum water/cement ratio through the use of water reducing admixtures:

  • SikaPlast® / Sika ViscoCrete® – mid and high range water reducing admixtures which decrease the volume of capillary pores and improve rheology and consistency

These active components work throughout the pores and capillaries structure of the concrete to effectively seal the concrete permanently against the penetration of water and other liquids.

The recommended maximum height:length ratio for pouring a watertight concrete wall over 1m high including Sika® WT-200 P is 1:30.

The maximum % of cement replacement that can be used in concrete mixes containing Sika® Watertight Concrete Powder is 70%.

Joint Sealing

The Sika® Watertight Concrete System also includes a range of complimentary jointing products to effectively seal construction joints and complete watertight structures:

  • SikaSwell® – a range of hydrophilic profiles and gun applied sealants, designed for the sealing and waterproofing of construction joints and penetrations (e.g. pipe entries)
  • Sikadur® Combiflex SG – high performance, over-banding sealing tape system for postsealing and waterproofing of construction and movement joints
  • Sika® Waterbar – internal or external applied waterstops based on PVC, TPO or galvanised steel for construction and movement joints
  • SikaFuko® – injection hoses for construction joints that can be used for sealing by injection and re-injection in the event of future movement

To find out more, download the Sika® Watertight Concrete System brochure.

To find out more visit Sika Waterproofing website.

To view Detail Drawings on the Sika® Watertight Concrete System and other Sika waterproofing systems. Please click here

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Sika Watertight Concrete WT-100 / WT-200 P / Sika® 1+


Sika® ViscoCrete®


Sika® Waterbar




Sikadur-Combiflex® SG