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Flood Testing for Building Leak Investigations

Before the introduction of electronic leak detection for testing of waterproofing membranes, which was pioneered in the UK by Thornton Consulting, flood testing was commonly used to establish the integrity of a waterproofing system.


Flood testing does have some disadvantages over electronic leak detection, however, hence the current popularity of the latter which can accurately pinpoint the location of a breach in the waterproofing, for example, where as a flood test will simply determine whether the roof is leaking or not.


Although less common these days, flood testing can still be an invaluable tool in some circumstances and is often used when undertaking building leak investigations to existing buildings where the waterproofing is buried.


Where roof finishes, such as paving or green roofs, remain in place, flood testing can be used to determine whether the waterproofing is functioning as required without the need for exposing the membrane, which would be required for an electronic test to be affective. This can ultimately save time and money and speed up the process of identifying the source of a leak.


Flood testing is also useful in other situations. When electronic leak detection is not possible, for example, where a deck is non- conductive (e.g timber), or the waterproofing membrane is conductive (such as EPDM), a flood test can be used to establish the integrity of the waterproofing.


It is also common to incorporate coloured dyes in a flood test which can confirm the source of the leak if more than one test is being conducted, or to more accurately locate the area of a leaking roof when undertaken in conjunction with other test methods.


Care needs to be taken with flood testing, so preliminary inspections and some preparatory work is usually required to determine whether the roof is suitable for testing.


We are always happy advise on the best solution for your project, so if you have any queries, please do not hesitate to contact our office on 01342 410508 or email


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