Drinking water is an essential provision that requires clean, watertight facilities to process and store it. Sika offers a wide range of DWI regulation 31 approved products for both new build and refurbishment projects.  

Water companies in England and Wales are set to invest
£14.4
billion in 2024-25¹
The water industry in the UK treats nearly
16
billion litres of water daily¹
In the UK over
3,031
Million litres of water leaks daily. ¹

The waterproofing of reservoirs and tanks containing potable water must be:

  • Durable over long periods
  • Easily maintainable
  • Certified and approved
  • Harmless to health
  • Allow swift return to service

 

 

Complete, Comprehensive Products and Systems

Hogsmill WTW project

Sika waterproofing products used in potable water reservoirs and tanks comply with the strict regulations of public water authorities. 

As the global leader in providing structural waterproofing solutions, Sika has the most complete, comprehensive range of products and systems. They are designed and can be adapted to meet the specific needs and requirements of owners of water reservoirs, architects, engineers and contractors on site.

Seal in Safety Today:

Types of Water Reservoirs

Tanks
Illustration showing type of water tank reservoir above ground tank
Towers
Illustration showing type of water tank reservoir above ground tower
Tanks
Illustration showing type of water tank reservoir below ground tank
Caverns
Illustration showing type of water tank reservoir below ground cavern

Typical Exposures and Tips for Design

There are many factors that may affect the degradation of water tanks and structures in water treatment plants. By understanding the cause of damage, you can better know how to treat it, repair it and prevent it from long-term deterioration. These are the most common exposures affecting water storage areas.  

 
General Considerations for Design and Specification
  • Durability and water-tightness
  • Exposures, site conditions and ecology
  • Easily maintainable
  • Safe and harmless to health
  • Compliant to local regulations
  • Compatibility of systems
  • Life cycle costing
  • Conditions for application
  • Return to service timeline

System Solution Overview

Illustration of Sika bitumen and sheet membrane waterproofing on external below ground structure or water tank
Sika illustration of concrete water tank below grade with White Box concept waterproofing
Sika illustration of concrete water tank below grade with Sikalastic liquid applied waterproofing
Illustration of Sika waterproofing and concrete repair on external below ground structure or water tank

1. External Waterproofing

To keep drinking water in below-ground storage tanks clean, it has to be protected from groundwater entering the structure.

Fully-bonded polymeric sheet membrane

Sika Solutions

Hot air welding application of SikaProof® A+ fully bonded waterproofing membrane

SikaProof® A+ pre-applied, fully-bonded TPO membrane

Spray applied liquid membrane
Sikalastic 8800 Application West Grove 2

Sikalastic® 8800  polyurea liquid applied membrane

Sikalastic M 689 polyurea liquid applied membrane

Application of Sikaproof waterproofing membrane on below ground structure

2. Concrete Solutions

The Sika Watertight Concrete System offers a comprehensive solution for watertight structures. The system consists of concrete that has been specially modified with Sika admixtures to produce waterproof concrete and carefully selected waterstops for construction and movement joints. Watertight concrete structures can be designed to keep water in or out, or both.

Waterproofing admixture

Sika Solution

Concrete ready for spraying

SikaControl® WT-250 P Crystalline powder

Sika®- 1+  Liquid hydrophobic pore blocker

Joint sealing

Sika Solutions

Sika waterbar water stop applied in poured concrete with rebar reinforcment construction site

Sika Waterbar® PVC and TPO waterstops for construction and expansion joints

SikaSwell® A hydrophilic swelling profile for construction joints                 

Sikadur-Combiflex® SG post-applied, bonded tapes for construction and expansion joints

Sikadur-Combiflex® 930  post-applied, bonded tapes for construction and expansion joints 

Sikadur-Combiflex® 933 post-applied, bonded tapes for construction and expansion joints 

Sikasil® DW acetoxy silicone sealant for joints in contact with potable water.

 

 

Sika Combiflex waterproofing tape at water tank concrete

3. Internal Waterproofing and Protection

Sika provides a wide range of different waterproofing systems and solutions. The selection of the best system for a specific project depends on many factors, including local water conditions. The most suitable waterproofing system depends on the nature of the reservoir structure and the water quality.

Waterproofing mortars

Sika Solutions

Retention pond in grassy mountains with potable water

SikaTop® - 581 Seal  Rigid cementitious slurry coat

SikaTop® -586 Seal multi-purpose cementitious levelling mortar

SikaTop® - 588 Seal Flexible and elastomeric, 2 component cementitious slurry

 

 

Liquid applied resins

Sika Solutions

Sika Sikagard waterproofing for water tank construction with scaffolding and workers

Sikagard®-62  epoxy resin with DWI approved, rigid coating or reinforced multi-layer system

Sikalastic M 808  2 component flexible polyurethane coating

 

Hot-spray membranes

Sika Solutions

Sika Sikalastic 840-ES spray applied waterproofing for water tank construction with worker on scaffolding

Sikalastic®-836 DW two-part, elastic, 100% solids, very fast curing and colored pure polyurea liquid applied membrane with good chemical resistance and WRAS drinking water approval.

Sheet membranes (TPO)

Sika Solutions

Sika blue waterproofing membrane on water tower foundation construction in Belgium

Sikaplan® WT 4220 polyolefin flexible homogeneous smooth sheet membrane with a glass fiber reinforcing inlay, WRAS approved for potable water, thermally welded

Sika spray applied blue waterproofing at water tank

4. Concrete Repair

When there is loss of water in reservoirs or tanks due to localized damage in the rigid waterproofing system, the appropriate repair must be done. It should be compatible with the waterproofing system, whether watertight concrete or lined with waterproofing mortar layers.

Concrete spalling

Sika Solutions

Man spraying mortar

Sika MonoTop®-1010 one-part, cementitious, polymer modified coating material used as bonding primer and reinforcement corrosion protection

Sika MonoTop®-4012 cementitious R4 concrete repair mortar containing recycled waste materials

Sika MonoTop®-615 one-component, polymer modified, high build repair and reprofiling mortar, meeting the requirements of Class R3 of EN 1504-3.

Joint sealing

Sika Solution

Sikadur Combiflex waterproofing tape being applied with hot air welder at concrete joint in Glattbrugg, Switzerland

Sikadur-Combiflex® SG  post-applied, bonded tapes for construction and expansion joints

SikaSwell® A hydrophilic swelling profile for construction joints

Sikadur-Combiflex® 930  post-applied, bonded tapes for construction and expansion joints

Sikadur-Combiflex® 933  post-applied, bonded tapes for construction and expansion joints

Sikasil DW Sikasil® DW is a one part acetoxy curing silicone sealant especially designed for joints in contact with potable (drinking) water.

 

Injection for crack sealing

¹Source: Water UK