Basement Tanking

BS 8102 is the British Standards Institute Code of Practice for Protection of Below Ground Structures Against Water from the Ground.

BS8102 gives recommendations and provides guidance on methods of dealing with and preventing the entry of water from surrounding ground into a structure below ground level.

BS8102 covers the use of;

Waterproofing barrier materials applied to the structure

Structurally integral watertight construction

Drained cavity construction

It also covers the evaluation of groundwater conditions, risk assessment and options for drainage outside the structure. BS8102 applies to structures which extend below ground level and those on sloping sites. Churchill provide specifications and install various waterproofing systems

With limited green belt sites to build on more building architects are looking to dig down and create basements or renovate existing basements.

Many commercial construction projects now have multiple levels below ground. The control of external water is essential to the success of such projects.

BS 8102 environmental grades can be condensed into three parts:

Grade 1: Some seepage acceptable as long as fit for purpose.  

Grade 2: No water penetration whatsoever, condensation/vapour acceptable as long as fit for purpose.  

Grade 3: No water penetration whatsoever, environmental controls necessary to prevent problems of condensation

Churchill provide permanent cementitious tanking systems such as Sika 1 system.

Sika® 1 Pre-Bagged Structural Waterproofing System mortars are pre-bagged kiln dried blends of specially graded aggregates and cements packaged in 4 grades at the appropriate mix ratios for optimum application performance and durability. When mixed with the diluted Sika® 1 liquid waterproofing admixture they provide the multicoat components for the structural waterproofing systems.

Sika 1 can be used in the following applications;

Internal waterproofing of below ground structures to meet the requirements of

BS8102 – 1990 Grades 1 - 4

  • Waterproofing of swimming pools and other water retaining structures
  • Waterproofing of basements, cellars and vaults
  • Waterproofing of tunnels

The alternative to tanking systems is to manage the water with cavity drainage. The cavity drainage sheets are fixed to the soffit and walls of the structure terminating within a drainage channel. The water is controlled and managed to a central point where it is pumped away. The pumps are fitted with flotation switches and are a proven cost effective solution and an alternative to tanking systems.