Author
Nigel Payne - Flat Roof Specialist
Why Is My Flat Roof Leaking?
Experiencing a leaking flat roof can often be disheartening and exasperating. It can mean a classroom out of action, or a tenant displaced. Along with the emotional rollercoaster often comes a significant financial burden too. All this is compounded if you are unaware of the cause. In this blog we will explore the possible reasons for a leaking roof and what the tell-tale signs are.
Condensation
If you are experiencing moisture inside your property there is a chance that it may not be coming from outside the property, but rather caused by condensation. Condensation may be caused by insufficient insulation or insufficient ventilation of a cold roof system.
Faulty Laps
Almost all leaking flat roofs come down to faulty laps. This could be because of poor installation. Finding faulty laps can be difficult if the faulty area is small but running a seam probe along the laps can help identify the problem area. The risk of water finding its way into a faulty lap is compounded by laps installed against the direction of flow of draining water and excessive ponding.
Penetrations
Sometimes the leak could be caused by a penetration in the waterproofing membrane. This could be caused by post-completion works or debris on the roof. This is a particularly larger risk if the waterproofing is made up of a single layer membrane such as PVC or EPDM.
Incorrect Termination
Failure to follow industry best practice leading to incorrect termination at details such as upstands and outlets can give water an easy route into the system. For example, ensuring that upstands are a minimum of 150mm above the finished roof level and terminate into a chase in the wall with a lead or alternative flashing sealed with a PU silicone is essential and failure to do so could compromise the details waterproofing integrity.
Other Causes
There is also a possibility that a leak may not have emanated from the flat roof at all. The water could be entering the system in any of these ways:
- Around windows and doors where there is a faulty seal or incorrect installation
- Through parapet walls where there is not sufficient damp proofing
- Through the wall where cladding may have failed, and vapour control measures are insufficient.
The Importance of Early Identification and Action
If the waterproofing system on your flat roof has been penetrated and there is evidence of water ingress it is important that you act fast. Acting quickly could be the difference between an overlay and a full strip up. In other words, it’s all about saving the thermal integrity of the insulation. If the problem is left too long the build-up of water can rend the insulation unusable and needing to be replaced. This will incur significantly larger costs.
If you are unsure what is causing a leak or just want to get a detailed report of the condition of you flat roof, contact us to book in a free, no obligation survey.
