How your Roof’s Drainage Systems Work to Prevent Water Damage

Proper water drainage is absolutely vital to the lifespan of your roof. If water builds up, it can speed up deterioration of your roofing material (such as shingles, SBS or EPDM membrane system, or tar and gravel/built-up roof).

Here are some of the other issues that can come up when water doesn’t properly drain:

  • Adhesives and caulking can loosen, which can lead to leaks
  • Areas around skylights, vents, and chimneys become weak when exposed to pools of water
  • Leaves and other debris can accumulate and lead to an unintentional ‘’living roof’
  • Pools of water or ‘’roof ponds’’ are a breeding ground for mosquitos–and no one wants more mosquitos!
  • Ice can form and cause stress on the roof, leading to warps, leaks or even a collapse!

In this article we’ll tell you all about your roof’s drainage systems and how they work to prevent water damage and extend the life of your roof.

The Shape of Your Roof Matters

We’ll start with the biggest factor in water drainage, and that is the shape of your roof. Obviously some roofs naturally allow water to flow off better than others. A hip roof will have water streaming down with the help of gravity, and a flat roof relies on interior drains and scuppers to help water find its way off your roof.

Some roofs have valleys in them, and those are typically the weakest points and most prone to leaks and water damage. The simpler the roof, the more waterproof it will be. You can read more about the different roof types on our blog.

Roofing Materials Affect Water Drainage

The best type of roofing materials for water drainage are the ones that are the smoothest. That means smoother materials like metal will be better than asphalt shingles, and roofs with membranes that have few seams will be better than roofs that have all kinds of vents, skylights, chimneys, etc. Whatever the material, if it’s properly installed, made with high-quality materials, and well maintained, water will drain right off.

Maintain your Eavestroughs and Downspouts

Getting water to flow off your roof is only half the challenge because once it’s off your roof, it needs to go somewhere! That’s where eavestroughs and downspouts come in. There are a couple things that need to happen for them to be effective for water drainage:

They must be installed at enough of an angle, or slope, to allow gravity to help water flow downward and away from your home.
They must be clean and clear of debris. Common causes of clogs are ice, leaves, seeds, pollen, and granules from shingles.

So keep an eye on your gutters and make sure they are drain away from your home or business.

Scuppers: What They Are and How they Work

There are two types of scuppers. One kind is basically a hole in a boat that allows water to flow off the boat and back into the ocean, lake, or sea. The one we’re talking about is for flat roofs where a hole in your raised edge or parapet wall allows water to drain off.

These holes are usually lined with sheet metal or copper, and water will flow through them and into an eavestrough or drain. Sometimes the scupper outlet has a flapper on it to prevent water from flowing back onto your roof. During heavy rain, they can be a life-saver for your roof, especially in combination with interior drains and sturdy, properly installed eavestroughs.

Interior Drains Protect Against Water Build-up on Flat Roofs

Not to be confused with scuppers, which are outlets in walls or the edge of your roof, interior drains are usually placed in the middle of a roof where they collect water. That water then flows into pipes below the roof and empties into a storm drain, a tank in the building, or is directed away from the building.

Interior drains are great for water drainage, and they aren’t as noticeable as a scupper. They’re also unlikely to freeze up because the drainage pipes are internal. The downside of interior drains is they can get clogged with leaves, asphalt, or other debris, so they need to be checked on a regular basis.

Are your roof’s drainage systems working they way they should?

Crest Roofing can inspect your roof for signs of water damage and give you a quote if your roof needs some repairs or replacement. Call us today to speak with a roofing expert at (780) 466-1601 or send us a message!


1 reply

Trackbacks & Pingbacks

  1. […] Mold can also be caused by improper drainage off your roof. Learn more about How your Roof’s Drainage Systems Work to Prevent Water Damage. […]

Comments are closed.