Different Sika solutions offer same superb waterproofing quality

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Mohamed Hussein

Mohamed Hussein - Mohamed Hussein is a Chartered Civil Engineer with a previous background in a number of construction disciplines including, Airports, Structures and Tunnels, as well as time spent looking at building defects for various insurance companies. He is currently National Render Manager at Sika and is CSSW qualified, ( Certified Surveyor in Structural Waterproofing), as well as holding professional memberships with ICE, CIWEM and CIOB

A proven waterproof solution is essential for safeguarding basements, car parks, tunnels and other below ground concrete structures against damp and water ingress. But which system is best suited to your building? A render-based product? A drainage system incorporating a membrane? Sika offers both solutions as part of its proven, wide-ranging concrete and waterproofing range, so let’s examine the benefits of each.

Sika®-1 Pre-Bagged

Sika®-1 Pre-Bagged waterproofing system comprises watertight renders and screeds produced using the Sika®-1 Waterproofing Liquid and Sika®-1 Pre-Batched Mortars. The mortars consist of a blend of special cement and kiln dried graded aggregates. Packaged in four grades, each is specifically designed for optimum application performance and durability.

Key considerations when specifying Sika®-1 Pre-Bagged:

  • Once applied, it requires absolutely no maintenance
  • It is more cost-effective when applied to areas of 300m2 or less
  • The render system takes up minimal space
  • Bonds directly to the substrate – follows the contours of any structure
  • Withstands high water pressure
  • Substrate preparation may be required

Sika® CD-Cavity Drain System

In terms of a water management solution, Sika® CD-Cavity Drain System uses a high density polyethylene internal drainage membrane to control water after it has penetrated a structure. The system is installed, loose-laid in flooring applications and attached to the wall with surface plugs in vertical installations. The system directs penetrating water into a drainage system and a collection sump before using a pump to discharge water from the building.

Key considerations when specifying Sika® CD-Cavity Drain System:

  • System requires ongoing maintenance and running costs
  • Requires more space to install
  • Acts as a vapour barrier
  • Limited surface preparation required
  • Can be used where the substrate does not have the strength to resist increased stresses caused by water pressure
  • Most cost-effective on areas larger than 300m2


Although varying in application and comprising different materials, the systems share common properties. For instance, Sika®-1 Pre-Bagged and Cavity Drain are suitable for new-build and refurbishment projects involving a range of below ground structures.

As well as being BBA-approved, both systems carry a Sika guarantee, Sika 1 specifically when installed by a registered contractor. Other common properties include the systems’ suitability for use for grades 1-3 according to BS 8102-2009, and high water table according to BS 8102-2009.

What then, must we conclude from this comparison? Well, by eliminating the need for ongoing maintenance, the Sika®-1 Pre-Bagged system is a more cost-effective solution over a lifespan of 60 years, particularly for structures 300m2 and below.

Not as simple to apply as the pre-bagged system, on account of its additional components, Sika® CD-Cavity Drain System is a more ideal waterproofing solution for areas larger than 300m2. Ongoing running costs are incurred, as the system requires regular maintenance.

Sika®-1 Pre-Bagged or Sika® CD-Cavity Drain system…whichever system you choose as your below ground solution, you are guaranteed the same quality: superb, long-term waterproof performance.

Sika® Registered Contractors Scheme

Sika operates a Registered Contractors scheme for the Sika 1 pre-bag system, designed to help facilitate the selection of suitable contractors to install Sika 1 waterproofing systems. Choosing a Sika 1 Registered Contractor provides total quality control – from product to service and installation – giving clients added reassurance that they will receive the highest standards of professionalism at every stage. The Sika 1 registered contractors are also able to offer a design and installation of the Sika CD Cavity Drain system with support from Sika.

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