Car parks leak for any of several reasons. In that respect, the requirement for a waterproofing layer to also act as a wearing course, with all the wear and attrition involved, is a very difficult combination to attain on a long term basis. The type of waterproofing should therefore take into account both traffic flow and potential aggressive driving conditions. For example, vehicles constantly turning on one point can have an extremely wearing effect, as a result of which early failure can occur.
Pavements, kerbs, light standards and entry / exit barriers all present potential for leaks. Finally, the surfacing to the car park needs to be clarified. For example, mastic asphalt is applied in two grades waterproofing and wearing courses. Alternatively, rolled asphalt, which is permeable to water, can be laid over the waterproofing.
Electronic testing of car park decks must take into account all these factors. Should the waterproofing be established as satisfactory, leak investigations will then need to be directed at other structural elements or services penetrations, for which Thornton Consulting has considerable expertise.