Understanding How Your Roof Works So You Can Make Better Repair Decisions

Roofs may seem simple, but they are actually a rather complex system. Since they take the brunt of damage from the winds, rains, falling debris and other elements, they must be designed to handle abuse for years on end with relatively little maintenance.

Homeowners that want to be able to make informed decisions about their roof should familiarize themselves with the technology. That way, they can talk more knowledgeably with contractors and make better purchase or repair decisions. To you help you become more acquainted with you roof, here is how it works:

The Basic Structure

Roofs must be created with a certain amount of slope or “pitch” so that any water or other substance that lands on it will roll right off. To give the roof this pitched shape, lumber is assembled to create an upside down “V” that extends past the building’s walls. The lumber that makes the “V” is called either rafters or trusses depending on how they were constructed.

Roof decking (sometimes called sheathing) is then nailed to the rafters in order to secure the stability of the roof, provide a base-level means to shut out the elements and to give the shingles a surface to be hung or nailed on. This decking is usually made from plywood or oriented strand board (OSB).

A felt underlay surface will be laid down on top of the decking to give it another layer of waterproofing and protection. Sometimes a waterproofing layer, reflective insulation or some other material will be used in addition to or instead of felt underlay, but this depends on the climate and the wishes of the homeowner.

To protect the exposed rafters’ edges, fascia boards are nailed along eaves and soffit material is used to cover up the space between the eave and the home’s exterior wall. A metal or plastic drip edge will be placed along the perimeter of the roof so that clinging runoff will not ruin the fascia or rafters.

Roofing Materials

There are many types of roofing materials that can be used as the first line of defense against nature. Metal, tiles, shakes and other exotic materials are popular, but by far the most common material used is the asphalt shingle.

Asphalt shingles (also called composite shingles) are an amazing invention that made roofing easier, cheaper and more manageable than ever. They can also last quite long too, only needing replacement every 10 to 20 years — sometimes longer.

Each shingle comes in a medium-sized strip with cut tabs that create an appealing-looking design. A base material such as felt or fiberglass is infused with resins to add strength and resistance to rot, water or other elements. Granules are embedded on top that add to the strength, durability and water repellency of the materials. The granules also help reflect sunlight and give your roof an attractive mottled pattern.

Roofers install shingles starting from the bottom so that each upper layer rests partially on the one below it, like fish scales. An adhesive is usually pre-formed onto the bottom of the flap so that when the sunlight heats the shingle it will automatically glue itself to the shingle below it. Roofers work their way up in rows until they reach the peak of the roof, referred to as the ridge.

Finishing Touches

Most ridges require a different type of shingle or other material to cap them off, appropriately called a “roof cap.” The ridge will likely have a vented space for air to circulate from the attic, letting excessively hot, moist or even dry air escape depending on the conditions. Other vents may be added to the roof to help maintain the ideal humidity and temperature levels in the attic.

Flashing will likely be needed to help waterproof areas not fully covered by shingles. This material is waterproof and corrosion resistant, almost always made from a metal like galvanized steel or copper. Roofers actually secure the flashing first so that shingles can be layered on top of it. Common areas requiring flashing are around chimneys, vents, gabled windows, ridges, valleys and on vertical surfaces such as on homes with two-level roofs.

Gutters are also necessary to divert runoff away from the home’s foundation.

These are just the most basic elements of a roofing system, but they should give you a clearer idea of how every component works together to protect your home. Talk with your contractor at length to determine the best course of action for each individual element when you need a repair, a replacement or a modification to your roof.

Always make sure to compare the price and reputation of local roofing contractors when asking for a roof repair or a new roof installation. ServiceWhale can make this process easy by providing real-time custom quotes from several Philadelphia area contractors, without the need for onsite estimates. Click here to get started.