BS 8102:2009 outlines three different waterproofing methods, the choice of which should take all of the relevant project requirements into consideration. The standard suggests consideration be given to the use of dual systems. For example, Type A plus Type B protection where the assessed risks are deemed to be high or the consequences of a failure to achieve the required internal environment are too high. Sika is able to offer a complete solution in these circumstances.
Type A (External)
A waterproofing barrier applied on the external surfaces that are exposed to ground water (positive side). The structure is protected against water ingress and also against any aggressive substances or influences.
For some materials such as post applied waterproofing mortars and coatings, access to the external surfaces is required for application after concreting.
- Grade of watertightness: Grades 1 – 3 plus additional requirements
- Application: New construction
- Protection provided: Waterproofing & concrete protection
- Durability: Low to high durability (dependent upon application)
Type A (Internal)
A waterproof barrier is applied on the internal surfaces of the structure (negative side). These systems do not prevent damage to the structure from water ingress, nor concrete damage due to aggressive chemicals.
Generally these systems are applied as coatings or sheet membrane linings, and are recommended for refurbishment works for example where access to the directly exposed surfaces is not possible.
- Grade of watertightness: Grades 1 – 3
- Application: Generally for refurbishment or as additional measures
- Protection provided: Waterproofing
- Durability: Limited durability (as the structure is unprotected)
Type B (Integral)
A waterproofing system integrated into the concrete structure. Liquid water penetration is stopped by the structure itself and cannot entirely pass through into the basement. Typical products are admixtures for watertight concrete combined with appropriate joint sealing systems for connections, construction and movement joints.
- Grade of watertightness: Grades 1 – 3
- Application: New construction
- Protection provided: Waterproofing
- Durability: Very high durability (for non-agressive ground water)
Type C (Internal)
The system directs penetrating water into a drainage system and a collection sump before using a pump to discharge water from the building.
- Grade of watertightness: Grades 1 – 3
- Application: New construction/refurbishment
- Protection provided: Waterproofing
- Durability: Limited durability (as the structure is unprotected)