Roof Systems

• Roofing professionals agree that a roof system requires good design, quality materials and proper installation to perform successfully. But once a roof system has been installed, nothing is more critical to its long-term performance than proper maintenance.
• Although building owners spend considerable time and resources on roof system purchasing decisions, many put little or no effort toward properly maintaining their roof systems. The situation is exacerbated by roofing professionals who do not educate their clients about the importance of proper roof system maintenance.

• A wide variety of roofing materials are used on today’s homes. Some of the more common materials are discussed below. Inspecting your roof is also discussed. If you discover signs of a leak or other roof problem, call a professional roofing contractor immediately before the problem and any related damage becomes worse.
• Many roofing materials come with manufacturer’s warranties. However, in order to make a claim on a warranty, you may need to know the manufacturer’s name, the place purchased and the installer’s name.
• In addition, if roof repairs are necessary, you will want to use roof materials that are the same brand, color and size as the original. If you record this information on page 1-5 when repairing or replacing your roof, it will be easier to assert a warranty claim or purchase replacement materials when needed.

• The most common roofing material is composition shingles. These shingles are made of organic or fiberglass material impregnated with asphalt. Colored mineral granules are embedded on the surface of the shingles. Many composition shingles are notched at regular intervals to form tabs. This creates the appearance of smaller shingles. Composition shingles should last for 15 to 30 years.
• During the roof inspection discussed below, you should look for shingles that are cracked, torn or curled. In addition, look for bald spots and accumulation of granules in the gutters. If you find damage, arrange to have the roof repaired as soon as possible. If the damage is extensive, it may be time to replace the entire roof.
• When repairing the roof, use shingles that remain from the original roof installation or try to purchase new shingles that are the same brand, color and size.

• Wood shingles and shakes are popular in many areas. Both shingles and shakes are made from western red cedar. Wood shingles are cut by a saw so they have a smooth, finished appearance. Shingles come in random widths and 16, 18 or 24 inch lengths. Shakes are thicker than shingles and are split by machine or by hand for a rough-hewn look. Shakes also come in random widths, with 18 or 24 inch lengths.
• Wood shingles and shakes usually last between 15 and 25 years. You can add to your wood roof’s life by hiring a professional roofing contractor to treat the roof with preservatives every five years to prevent decay. Wood shakes should be replaced when the wood crumbles easily between your fingers.
• Look for moss or mildew growing on the wood shingles or shakes during the roof inspection discussed below. Tiny roots from these organisms penetrate the wood, allowing water and the elements to damage the shingles or shakes and speeding decay. If you find moss or mildew on wood roofing, call a professional roofing contractor to treat your roof.
• During the roof inspection, you should also look for shingles or shakes that are curled, broken or split or that have been lifted by the wind. If you find damage, arrange to have the roof repaired as soon as possible. If the damage is extensive, it may be time to replace the entire roof.

• Tile roofs are high quality, no-maintenance roofs. A tile roof should last 20 to 50 years or longer. It is not uncommon for tile roof manufacturers to guarantee their products for 40 or 50 years.
• One precaution, do not walk on a tile roof for any reason. The weight of a person can break the tiles. Broken tiles may allow water to leak into your home. Call a home maintenance professional if it is necessary to go up on your tile roof for any reason.
• If you notice a buildup of moss or debris on your roof tiles during the inspection discussed below, you can have a professional contractor rinse your roof with a pressure washer. However, do not walk on the roof yourself to perform this task.
• During your roof inspection, look for any tiles that may be damaged or broken. If any repairs appear to be needed, call a professional roofing contractor.

• Cement-fiber shingles are a relatively new roofing material. As the name suggests, cement is mixed with a fiber, such as wood chips. The result is a durable, versatile, light weight, long lasting roof material. Cement-fiber shingles can be formed to resemble natural materials such as wood shakes, slate shingles and clay tiles or different looks can be created.
• Manufacturer’s warranties of 30 to 50 years indicate the long life of this product. Like tile roofs, little maintenance is required for cement-fiber shingles.
• If you notice a buildup of moss or debris on the shingles during the inspection discussed below, you can have a professional contractor rinse your roof with a pressure washer. During your roof inspection, look for any shingles that may be damaged or broken. If any repairs appear to be needed, call a professional roofing contractor.
• A unique trait of cement products is a white powder that can form on the product’s surface. This natural process is known as efflorescence. If a powder forms on your shingles, you can have the shingles rinsed to restore their natural state.

• Slate shingles are a natural, long lasting roofing material. They can last for 30 to 100 years, or longer. Although slate shingles are extremely durable, they are brittle and expensive to replace. Do not walk on your slate roof for any reason. If you have any problems with your roof, contact a professional roofing contractor that is experienced with slate roofs. Do not settle for anything less than an experienced slate roofing contractor.
• If you notice a buildup of moss or debris on the shingles during the inspection discussed below, you can have a professional contractor rinse your roof with a pressure washer. During your roof inspection, look for any shingles that may be damaged or broken. If any repairs appear to be needed, call an experienced slate roofing contractor.

• Metal roofs come in a variety of materials and shapes. Aluminum, steel and copper are common metal roofing covers for homes. Aluminum does not rust and is coated in a variety of colors. Steel is also color coated for style and corrosion protection. Since copper does not rust, copper roofs are not coated. This allows the distinctive color of the copper to add to the character of the home. Metal roofing can be formed into shingles, tiles and sheets.
• If properly maintained, a metal roof should last 40 years or longer. When inspecting a metal roof, as discussed below, look for rust spots. If rust appears, you can preserve your roof by having a professional roofing contractor scrape the corrosion off and paint the roof with special paint or compounds. Re-paint the roof as needed to preserve its life.
• Inspect a metal sheet roof by looking for cracks or open joints at the soldered seams. As the metal sheets expand and contract, stress is placed on these joints. The stress can break the seal and cause leaks. Have any problems repaired by a professional roofer.
• When inspecting metal shingles or tiles, look for loose, missing or damaged shingles or tiles. Have any problems repaired by a professional roofer.

• Built-up or “tar-and-gravel” roofs are found on flat or low-sloping roofs. Layers of roofing felt are covered with alternating layers of roofing tar to form a continuous sealed surface. The top layer is covered with rock or crushed gravel to protect the roof from the sun, wind and rain. This roof is given its name because it is “built-up” into several layers.
• Built-up roofs should be inspected regularly as discussed below. During the inspection, look for patched areas, cracking, blistering, surface erosion, alligatoring and wrinkling. Look for cracks at roof joints, near roof mounted structures and the flanged metal strip along the roof perimeter. All leaks, cracks, blisters and other problem areas should be sealed or patched and sealed.
• Do not step on any blisters when walking on your roof. Blisters are usually caused by air or water vapor trapped between layers of roofing felt. A person’s weight on a blister can crack the roofing felt.
• Record the location of any cracked or patched areas on a work sheet. Look inside your home for leaks around the areas noted on the work sheet. Save the work sheet in this Home Owner’s Manual for future reference.
• Built-up roofs should last 10 to 20 years, depending on the sun’s intensity. Erosion of the gravel, dry felt and blistering are signs that your roof is due to be replaced.

• Another material used on flat or low sloped roofs is mineral felt or roll roofing. The material comes in rolls of roofing felt that has been impregnated with asphalt. Colored mineral granules may be embedded on the surface of the material. One or two layers of the roofing is applied over the roof’s surface. Joints are sealed or the entire surface is coated with tar.
• During the inspection discussed below, look for blisters, cracks and eroded, torn or curled sections. Look for cracks at roof joints, near roof mounted structures and along the roof perimeter. All leaks, cracks, blisters and other problem areas should be sealed or patched and sealed.
• Do not step on any blisters when walking on your roof. Blisters are usually caused by air or water vapor trapped between layers of roofing felt. A person’s weight on a blister can crack the roofing felt.
• Record the location of any cracked or patched areas on a work sheet. Look inside your home for leaks around the areas noted on the work sheet. Save the work sheet in this Home Owner’s Manual for future reference.
• Roll roofs should last 10 years or so, depending on the sun’s intensity in your area. Erosion of the surface, dry felt and blistering are signs that your roof is due to be replaced.

• Single-ply membrane roofing is a relatively new material for flat or low sloped roofs. A single sheet of thin rubber or resilient plastic is glued or fastened to the roof’s surface. A layer of stones may be added for extra protection.
• During the inspection discussed below, look for cuts, gaps, blisters, wrinkles and open seams in the protective coating. Look along joints, near roof mounted structures and along the roof perimeter. All leaks, cuts, blisters and other problem areas should be sealed or patched and sealed by a roofing contractor familiar with the material. Your membrane roof should last 15 to 25 years.

• Building owners’ purchasing decisions typically are influenced by warranties provided by either roofing materials manufacturers or roofing contractors. There is a common misconception among some building owners that long-term warranties are all-inclusive insurance policies intended to apply to virtually any roofing problem, regardless of cause or circumstance. As a result, after a new roof system that features a long-term warranty is installed, a building owner may neglect or ignore the need for roof system maintenance.
• However, most roof system warranties are reactive, rather than proactive, solutions to roofing problems. For example, most warranties provide for only limited repairs once a roofing problem (e.g., leakage) is detected if the problem is included within the warranty’s limited coverage.
• Also, most roof system warranties contain specific provisions that require building owners to properly maintain roof systems during the warranties’ terms. A warranty does not replace the need for roof system maintenance.

• The intent of preventative maintenance is to enable building owners to proactively identify and implement solutions to roof system problems before they become widespread. In many cases, if a problem is identified early and properly repaired, the extent and cost of repairs will be significantly less than if problems were unattended.
• NRCA recommends building owners schedule roof system maintenance inspections at the very least biannually. These inspections can be conducted by a building owner’s personnel if they have a general knowledge of the roof system and follow proper roofing safety procedures. If a building owner does not have his own personnel or is not comfortable having them perform roof system maintenance inspections, a professional roofing contractor should be retained.
• A preventative-maintenance inspection typically consists of a thorough visual inspection of a roof system and its adjacent surfaces (e.g., walls), as well as mechanical equipment that can impact the roof system’s waterproof integrity. Conditions typically are recorded in writing and photographed, and the documentation should be maintained in a file. Such a file can be useful during future inspections because it can provide a basis for comparison of changing roof system conditions.
• During an inspection, it is recommended that any debris or other materials that do not specifically belong on the roof be removed. If repairs are necessary, routine repairs sometimes can be carried out immediately. If repairs cannot easily be made at the time of inspection, they should be implemented as soon as possible to avoid further roof system deterioration. NRCA recommends a professional roofing contractor conduct any repairs beyond what would be considered routine.
• An additional benefit of establishing an ongoing preventative-maintenance program is that it allows for a planned, organized approach to management of a roof asset, as well as for responsible, timely preparation of long-term capital expenditures.

Skylights:

• Skylights should be inspected from both the roofing side and the inside. Items to look at on the outside of the roof are:
• Skylights should have adequate curbs, whether they are manufactured units or not. Skylights without curbs or with inadequate curbs do not allow for proper step and counter flashings, and are destined to leak. Some adhesives/sealants are better than others, however, without proper flashings, the skylight seal would not be considered dependable and the installation of proper flashings should be anticipated.
• The skylight curb height on a sloped roof should be approximately 4 inches, for a flat roof; it should be 6 to 12 inches, depending on the potential for snow in the geographical area.
• The flashing detail around skylights, particularly those installed after the original construction, is frequently improper. The most common problems are improper or non-existent step and counter flashings, lack of adequate curbs and failed thermal seals.

Solar panels:

• Solar panels mounted on a roof  are frequently defective. The major problems with solar panels are:
• The areas where they are fastened to the roof are typically tarred over with roof cement, will eventually open up and leak.
• The framing (i.e., truss/rafter) beneath the solar panel may not have been reinforced to receive the areas that bear on the roof or to accommodate the additional weight.
• Leaks are relatively common. In some cases, these panels are drained and abandoned in lieu of repairs.

Antennas:

• Antennas secured to a roof or chimney are vulnerable and may cause problems. The reason is that they are normally anchored to the chimney, roof and/or the structure with guy wires that may be stressed during high winds. And over time, they may create stress points at the fasteners, which may become loose and weak.

Chimneys above the roof:

• While on the roof, evaluate the chimneys above the roofline. The masonry chimneys may have multiple flues. If the chimney is only one brick or 4 inches thick, and without a liner, it is defective. To be safe, a one brick chimney must have a flue liner all the way to the firebox on the bottom. A chimney two bricks or 8 inches thick does not require a liner. Cracked mortar, spalling bricks, or cracked caps are very common defects.
• The reason chimneys deteriorate at the top most quickly is that they heat up and then cool off during the winter months, in rapid succession, causing the bricks to crack, and allowing condensing water to penetrate. The penetrating water can then cause deterioration, or even worse, could freeze, expand and cause larger cracks. When possible, look down the chimney to ensure that the terra cotta liner or the brick is in good condition.
• Metal chimney flues, normally for gas or oil-fired heating plants, should also be inspected above the roofline. These metal units should have a weather cap installed on them, and should not be rusted out. The individual sections should be screwed together.
• Large metal pans that are installed at the top of some metal chimney structures should be convex to assure proper shedding of water. In some situations, the metal chimney is hung from this pan, causing it to distort and become concave. There is a collar in the pan that goes around and is screwed to the metal chimney. This collar may likely keep the pan from leaking for 10 years or more, however, it may eventually fail, and all of the water that lands on the pan will fall into the chimney structure. Check the top of metal chimneys. If you are unable, inspect the area around and adjacent to the chimney for even remote water stains.

Overhanging trees:

• Overhanging trees or brushing on a roof are not a defect unless they are actually causing damage. If leaves are lying on the roof, they may be causing moisture damage to the roof sheathing. This typically will not be visible, so check the ceiling below the area that the leaves are located for even the most minor stain, and carefully try to walk the roof in the area that the leaves are located. If the house is older and it appears that the leaves lay in one area for months at a time, it is possible to have severely weakened sheathing. If shingle granules are worn off, it is suggested that the tree be cut back and the roof be repaired, if necessary.

• To ensure roof systems last the duration of their service lives, roofing professionals should provide building owners with information regarding the importance of proper roof system maintenance.
• Several roofing materials manufacturers have developed documents detailing the need for proper maintenance. These documents are intended to be provided to building owners at the end of roofing projects when manufacturers’ warranties are delivered.
• NRCA also offers useful roof system maintenance information to building owners. NRCA publishes two Consumer Advisory Bulletins and three inspection, maintenance and repair documents that are directed toward building owners of built-up, modified bitumen, single-ply and spray polyurethane foam-based roof systems.
• Whether roofing professionals use the documents provided by roof system manufacturers or NRCA or develop their own materials, they should convey the importance of proper roof system maintenance to building owners.