With limited space a problem for many domestic and commercial property owners, the option of utilising the available area below ground level is becoming a viable solution.
Many older properties may have exisiting basements which can be turned into habitable areas by selecting the correct waterproofing system for the type of construction and required usage for the area. Careful selection and detailing of the correct solution can prevent costly and time consuming issues after the area has been inhabited!
Various levels of watertightness are defined in BS8102:2009;
- Grade 1, Basic Utility – Some seepage and damp areas tolerable. (Underground Car Parks, Plant Rooms)
- Grade 2, Better Utility – No water penetration, ventilation may be required. (Storage areas, workshops and electrical plant rooms)
- Grade 3, Habitable, No water penetration, totally dry. (Ventilated residential and office, restaurants, leisure facilities)
- Grade 3+, As per Grade 3 plus consideration to controlling internal environment to provide ventilation. (Computer Rooms, archive storage)
BS8102:2009 Outlines 3 different types of waterproofing methods;
- Type A – A waterproof barrier either applied to the internal or external face of a structure.
- Type B – An integral waterproofing system built into the structure
- Type C – A drained waterproofing system
There are a range of solutions available to all of the above requirements; Internal multi-layered cementitous renders. External fully bonded sheet membranes and liquid applied systems. Watertight concrete systems that can be integrated into the construction of a below ground structure. Cavity Drainage systems including pumps and sumps. Many solutions are ideally suited to existing structures or ones which are being built.
Detailing is an important aspect of any waterproofing system and careful consideration need to be given to joints and penetrations, constraints on methods of application, program, ingress of water and the substrate it needs to be applied to.