Stay up-to-date with

News and Events

Learn the Anatomy of a Commercial Roof

Learn the Anatomy of a Commercial Roof

You don’t have to have something wrong with your roof to schedule an inspection. However, learning the anatomy of a commercial roof will give you the understanding you need when it’s time for a professional to examine all of your rooftop layers. Knowing the parts of a roof will help you understand what is going on before a contractor starts any work on it.

Roofing Layers From Bottom to Top

Some multi-layer rooftop coverings might have these layers in a different order than what you see below. This description shows the typical order from the bottom of your roof to the topmost part of it.

Structural Deck

It’s often made of wood, but your building might have one constructed of steel, concrete or other durable materials. Sometimes, the steel beams might have a gypsum covering around them. In any case, this layer holds up your entire rooftop, so it’s an important layer. It’s wise to have it inspected as often as possible.

Vapor Control Layer

You’ll usually find this thin sheet of material above the structural deck. It might consist of fiberglass, sheet metal or another substance that will help control moisture levels. The VCL can extend a roof’s lifespan and attaches to the insulation layer. If your building feels humid, this covering might need replacement or repair.


On a roof, usually rigid insulation layers work the best. Various types of poly plastics will sit over the top of the VCL and attach to it. ISO boards also seem to provide climate control for a commercial building, so you might see that if you take a look at what makes up your roof. In any case, your energy bills will skyrocket unless you make sure your insulation stays intact.

This thin layer keeps out the rain and wind, which further regulates your commercial building’s inside temperature.


You’ll need this to hold your roofing materials to your structural deck. It also attaches the insulation with the top layer, which usually is the weatherproof membrane. Make sure your materials attach well in between each layer and to the roof deck itself.

Weatherproof Membrane

It’s the topmost covering of your roof. You might have one made of asphalt or rubber, but your roof also could have one made of a variety of thermoplastics such as TPO or PVC. This thin layer keeps out the rain and wind, which further regulates your commercial building’s inside temperature. All your roofing layers serve a purpose but making sure this one has no rips, tears or holes in it will provide an emergency fix until your next scheduled repair.

Even if you think your roof is fine and no storm has occurred, schedule your commercial roofing inspection in Atlanta if you haven’t had one yet this season. Is it an emergency? Call Rosie’s Roofing & Restoration immediately at 888-502-0221.

Contact Us

View our business page on the Better Business Bureau View our Business' Page on GuildQuality We are proud to be an Owens Corning Preffered Contractor We are proud to be a part of UASRC Rate and Review me on Kudzu! Click here to see Rosie's Roofing and Restoration's Profile.