Flat roofs remain popular commercial building options, as they allow for large installations, like air conditioning systems. They also provide easy access for maintenance and repairs and can function as rooftop decks or gardens. Understanding the components of this type of system helps you keep it in good condition. The following guide details a few important parts of a flat roof. 

What Are the Main Parts of a Flat Roof?

1. Deck

Wooden decking materials create the roof’s structure and function as its “skeletal” support system. It's typically made of plywood planks or boards, and the high-quality products naturally provide the durability and longevity necessary for a safe, sturdy roofing system. Additional layers are built on top of this base. They include materials that protect the wooden components from water damage that can lead to wood rot and mold growth, which can compromise the deck's structural stability.  

2. Insulation

flat roofs

Fiberglass mats are often used as flat roof insulation, as they keep the system cool and dry. This prevents moisture and condensation issues that encourage wood rot and mold growth. Quality insulation also contributes to the building’s energy efficiency since it prevents the HVAC system from working overtime. The vapor barrier also contributes to a cool, dry roof by keeping damp air and rainwater from entering the rest of the system and the building. 

3. Drains

While gutters can be installed on flat roof systems, most structures feature a mix of inner drains and scupper boxes. The customizable inner drains look like upside-down strainers that protrude from the roof. As rainwater flows into them, it's directed to an adjoining drain within the building. There must be enough inner drains to accommodate the roof’s size; otherwise, the risk of ponding increases. Standing water attracts insects and adds weight to the roof, which can lead to damage. 

Scuppers are openings on a commercial building’s outer walls. They are square-shaped and allow water to drain without touching the siding materials.


Whether you need a flat roof installed, repaired, or replaced, count on Triad Roofing & Services in Strasburg, OH. These licensed and insured commercial contractors specialize in single-ply roofing systems. They also offer acrylic roof coatings that come with 5-, 10-, or 20-year warranties. Call (330) 556-5441 to request an estimate, or visit the website to learn more about this reliable company's products and services.