Behind The Scenes Of Water And Your Flat Roof

Flat roofs offer simple, modern looks and are also durable and resistant to persistent environmental conditions. The main challenge which comes with flat roofing is ensuring proper drainage and preventing leaks.

Heavy rain and hail pound down on all roofs, but if you have a flat roof, water may collect on your rooftop for longer, especially in areas where depressions have formed. When your roof doesn’t have proper drainage solutions and waterproof coating, pooling water and leaks will be persistent problems which can lead to structural damage.

Importance of Proper Flat Roof Drainage

Flat roofs aren’t fully flat. They are designed with a slight pitch to direct water towards the drains, which then take the channeled water off the roof and away from the foundation. If your roof is not fitted with a proper drainage solution or the existing one is not working to its full potential, water will puddle up and stand around.

Ponding water can contribute to several problems:

  • Wear on the roofing materials – If pooling water is allowed to go on too long, it will degrade roofing materials. Water will break down the roof coating, barrier membrane, and seams due to photo-oxidation.
  • In the intense Florida sun, standing water will act as a magnifying glass, focusing and intensifying the UV rays passing through it. This can result in premature flat roof replacement.
  • Leaks – Areas that crack, stretch, or sustain severe damage become susceptible to leaks. Also, leaks can develop at the overlapping seams as the membrane loses its seal.
  • Sagging roof – Flat roofs aren’t designed to hold water on them. The substantial weight of ponding water can cause unnecessary stress on the roof structure, leading to sagging.
  • Plant growth – Moss, algae, and other plants will take advantage of ponding water and debris those piles up. Major structural issues can occur when the root systems penetrate the roof surface or clog the drain.


An efficient flat roof drainage system optimizes gravity to move the water from the rooftop to the ground. The drains are typically fitted at the lowest point of the roof.

Gutters are the most commonly used, easiest to install, and most cost-effective drainage solution for flat roofs. Gutters catch rainwater as it flows off the edge of the roof and directs it to a downspout. This keeps water from pouring in an uncontrolled manner and protects the siding, windows, and doorways from water damage.

Gutters can be attached to the edge of the roof without any major modifications. However, they need regular cleaning to get rid of debris and maintain their efficiency.

Waterproofing Your Flat Roof

Waterproofing is a simpler, cost-effective way to protect your roof and home from serious water damage. A waterproof membrane provides an additional layer of protection from leaks, wear, and tear. At the same, it reflects UV rays, reducing the impact of excessive heat on your roof and improving your home’s energy efficiency. Waterproofing extends the life of your roof and reduces the frequency of repairs and replacements.

The material and method of waterproofing ideal for your roof will depend on several factors like the environment, size of the roof, the type of roof covering used, and the budget. The main waterproofing options include:

  • Reinforced bitumen membrane which can be attached to the roof by torching, cold application, pour and roll, and self-adhesive.
  • Liquid waterproofing which can be rolled on cold or sprayed. Examples include fleece liquid membranes and fiberglass membrane.
  • Single-ply membranes can be attached to the roof by fastening, adhesion, or ballasting.

Our technicians at Alan Roofing can help you choose, install, and maintain the right waterproofing material and drainage system for your flat roof. Contact us today to schedule a roof inspection for your Central Florida home.