4 Types of Roof Drainage Systems

What Drainage System is Best for Your Home’s Roof?

Our Simple Guide to Roof Drainage Systems

If you’ve ever had water damage in your home, the roof drainage system may be to blame. A roof with standing water often sustains structural damage, encourages plant growth and compromises its integrity.

Installing a roof drainage system protects your roofs from water damage, ultimately reducing repair and maintenance costs.

Why Is It Important To Have a Roof Drainage System?

Many homeowners are unaware of a roof drainage system’s value until their roof leaks. A well-installed roof drainage system is essential for getting water and debris off the roof and preventing water from pooling near the foundation.

Types of Roof Drainage Systems

When people think about roof drainage, gutters nearly always come to mind. However, there are numerous more roof drains in addition to this common solution. Below we will go into more detail, including the pros and cons of the different types of roof drain systems.


Roof gutter systems are the go-to solution for many property owners to safeguard their roofs from water damage. They are reasonably priced and can adequately protect your doors, windows, siding and foundation from water damage. Aluminum, vinyl, and galvanized steel gutters are the most common materials for gutters, with aluminum being the most durable.


  • Inexpensive – easy to get and install
  • Applicable for all types of roofs
  • Protects doorways and windows
  • Protects your foundation and prevents soil erosion


  • High maintenance – gutters should be cleaned regularly to avoid clogging
  • Winter freezing may cause gutters to become brittle and crack


Scuppers come in the form of an opening in the outer walls. They are designed to drain roof water into the ground or a designated drainage area, making them perfect for properties with flat roofs.

Scuppers function better in drier, warmer areas with less rainfall. Consider combining a rainwater collector with scuppers or gutters.


  • Comparatively more affordable than inner drains
  • Little maintenance needed
  • No clogging issues if the scuppers are wide enough
  • Custom scuppers can add architectural appeal


  • Small scuppers clog easily
  • Wider ones would be better, but they are usually not available
  • Any runoff has to follow gravity in one direction, which can flood some areas if you don’t have enough angle in your roof

Inner Drains

Commercial properties often have inner drainage installed under the roof or parapet wall to keep the space looking nice. Inner drains are commonly installed on commercial buildings with sloped roofs and high-rise structures to prevent flooding or pooling in the gutters.

This drainage system is usually installed in the middle of the roof or wherever the slope is oriented. In most cases, inner drains are controlled by a lower roof drainage system that directs water flow away from the building, usually to a nearby rain gutter.


  • Aesthetic
  • Allow you to make the most of the space on your roof
  • The best drainage type since the pipe is not in contact with the roof or parapet wall
  • In case of a leak, the water is drained away.


  • Expensive to install, maintain and repair
  • If pipes are clogged, the outcome can be extensive water damage.
  • Damaged or leaking pipes will eventually cause casing damage, resulting in water entering the living space,

Siphonic Roof Drain

The siphonic roof water drainage system is the most often installed water drainage system. This system relies on the roof’s slope to generate an undertow that lifts debris and collects water off the top surface of the roof, requiring minimal cleaning and maintenance.

It is commonly used for flat roof drainage systems because it drains water faster than other roof drainage systems.


  • Lower installation costs
  • Drains water faster
  • Fewer outlets linked to a single leader drainage pipe


  • Quickly clogged by the plant matter/leaves
  • Regular maintenance required

Choosing the Right Roof Drainage System With JET Contracting

No one wants to deal with water pooling or excess water on the roof. If you’re unsure which type of drainage system, including underground drainage systems, will work best for your home or commercial building, we can help.

JET Contracting is a full-service roofing contractor specializing in all types of commercial roof drainage systems and can give you an expert opinion on which type will work best. We have over 20 decades of commercial roofing experience and know the right way to handle any job.

Get in touch with JET’s expert staff today to learn more about our offerings.

Recent Blog