DIY Solutions for Water Ponding On Flat Roofs

Water Ponding On Flat Roofs

Water ponding or water pooling on flat roofing is not a new issue and can, over time, cause larger issues such as; leaking, structural damage to the roof, and premature wear of the EPDM membrane, if not resolved.

What is flat roof ponding/pooling?

Water ponding/pooling refers to gathered surface water on a flat roof, and which has not drained in longer than 48 hours. EPDM is incredibly efficient at rejecting water absorption; however, without sufficient drainage, this can lead to ponding which can put excess structural stress on the roof over time, and actively encourage vegetation to grow.

Identifying the cause of roof ponding/pooling

Before working to resolve the water pooling/ponding issues, a solid understanding of the cause is necessary; we recommend a thorough investigation of the flat roof, paying close attention to any area(s) where water is collecting, or not draining properly. Ponding will typically occur in low-lying areas where the roof may have sagged, or where debris has accumulated which is blocking the draining flow of water.

Fixing Water Ponding on EPDM Flat Roofs

There are several steps which can be taken before and after water pooling has occurred:

Keeping Your EPDM Flat Roof Clear Of Debris

Debris on a flat roof can lead to water drainage paths becoming blocked; it is important to remove leaves, dirt and other obstructions which may be hindering the flow of water across the roof’s surface.

Evaluate Flat Roof Roof Slope

Although deemed “flat roofs”, an installed EPDM roof is technically not flat, and current regulations mean that a flat roof must have a fall of 1:80 (1ft slope per 80ft run). Evaluating the slope, and ensuring that this meets the regulations is important, and should be a prime consideration before installation. Not meeting this requirement could result in the eventual replacement of the current EPDM roof.

Improving Roof Supports

In many instances, pooling can be caused by bowing in the substrate, normally caused by the natural shifting of the structure over time. If this occurs, installing additional support of the roof structure may be required to help remedy the low spots where water is pooling.

Additional Help & Advice

As the UK’s preferred supplier of techno EPDM, we offer support and advice to both DIYers and contractors alike. We love our product, and we understand the benefits to both residential and commercial properties that EPDM can bring.

We offer on-site training, whether you’re an enthusiastic DIYer or a seasoned roofing veteran. We also offer an EPDM calculator to help you calculate the cost and requirements of your next roofing project.