Your roof is one of the most important parts of your home's building envelope. Proper care and maintenance are critical to the integrity of your roof.

In order to provide the type of care that your roof deserves, you must have an understanding of the many layers that make up your roof. Get to know your roof better by learning more about the three major layers that make up a residential roofing system.

Insulation and Support

The foundation of your roof is a support system made of wood or metal joists. These joists are the bones of your roofing system. They help to keep your roof firm and strong in the face of heavy winds or severe storms.

Insulation is fitted between each joist. The primary role of insulation is to control the transfer of heat between your home's interior and the outside environment. Common insulation materials found in roofing systems include fiberglass and spray foam.

The quality of your insulation can determine how energy-efficient your home will be in the future.

Underlayment and Decking

The main layer of most residential roofing systems is the decking. Decking is typically plywood that is laid over the insulation and support joists to create a flat surface. Strong decking helps to ensure that your home's roof will be able to retain its structural integrity over time.

An underlayment is laid over the top of the roof decking. Underlayment is a critical component in any roofing system because it is the underlayment that creates a waterproof barrier.

A thick and durable underlayment will help to prevent leaks and keep roof damage to a minimum over time.


Asphalt shingles are one of the most popular materials used to create the outermost layer of a residential roof. Shingles are installed over the top of the underlayment.

It's important that only professional roofing contractors be allowed to install asphalt shingles. Piercing the underlayment with a roofing nail or staple during the installation process could create roof leaks in the future.

The shingle layer on your roof is exposed to the elements at all times. This means that this layer is the most prone to damage. Be sure to conduct routine visual inspections of your shingles often so that you can determine when repairs are needed to maintain the integrity of the shingle layer.

An understanding of the major layers of your roof can help you better maintain this valuable asset in the future.