Tips
Winter, Spring, Summer, Fall…your roof is the first line of defense against the ever-changing, onslaught of threatening conditions that can attack your home or commercial property. That may sound ominous, but it is a simple fact. Weather and time are the biggest enemies to the integrity of your roof. The following tips are here for you to use, to help ensure that you get the longest life from your roof and the best protection for your investment.
Tip 1
Fall Debris on roof and in gutter
Roof system components
All steep-slope roof systems (i.e., roofs with slopes of 25 percent or more) have five basic components:
1. Roof covering: shingles, tile, slate or metal and underlayment that protect the sheathing from weather.
2. Sheathing: boards or sheet material that are fastened to roof rafters to cover a house or building.
3. Roof structure: rafters and trusses constructed to support the sheathing.
4. Flashing: sheet metal or other material installed into a roof system's various joints and valleys to prevent water seepage.
5. Drainage: a roof system's design features, such as shape, slope and layout that affect its ability to shed water.
Tip 2
House plumbing vent flashing is required around the pipe at its roof surface penetration. Without it, or if improperly installed, rain water or melting snow will seep around the vent and damage the roof decking material, sometimes making its way down to the wall / ceiling surfaces inside the property.
Depending on your roofing material and roof slope, there are different types of plumbing vent flashing that can be installed and NO – roofing cement is NOT one of them.
Plumbing vent flashing manufactured specifically for this application creates a waterproof / watertight seal around the roof-penetrating pipe without the use of any sealants. The most common types of materials used for this purpose are:
• neoprene rubber
• sheet metal with a neoprene rubber insert
• lead
There are also more sophisticated and expensive copper or galvanized steel plumbing vent flashing types assembled from two or more pieces. While serving the same purpose, they also add appeal to your house’s roof.
Neoprene rubber flashing and sheet metal with neoprene rubber types are very easy to install, but you have to keep in mind that water will penetrate it if you fail to do it right. The most common mistake is placing the flashing on top of the sloped roof surface material (shingles, rolled composition, metal, etc.) and applying roofing cement or caulking around it.
Top and side edges of the plumbing vent flashing apron (this section is mostly hidden under the roofing material) have to be inserted under the slope roof surface material with the bottom edge exposed. That open bottom edge prevents any possible condensation from the pipe sweating from being trapped under the roofing material, and can eventually cause roof decking damage or mold growth in the attic. Any other installation is un-professional and will most likely fail over time.
Although neoprene rubber has a long life span, it might eventually crack along the seam with a plumbing vent pipe, and at that point, I would definitely recommend replacement. If you’re able to pick a warm day for this procedure, it might be possible to slightly lift the top shingles (they will split / break if it’s cold and you will need to replace them) and replace the flashing without causing any damage. You can use a hacksaw blade to remove nails holding down shingles located above the plumbing vent stack and the vent stack flashing itself. Just slide the blade underneath the surface and cut any nail that prevents flashing removal.
Q: Why roofing cement should not be used as a permanent plumbing vent flashing:
A1: Because every roof structure contracts and expands independently from the plumbing vent stack
A2: Because every building settles differently from the plumbing vent stack
Both of the conditions (A1 & A2) will cause roofing cement applied around the plumbing vent stack to crack, separate from the pipe, and eventually leak water.
Tip 3
If you're collecting dripping water in a pot beneath your roof, you may want to inspect the roof flashing. Anywhere surfaces intersect on a roof is a prime spot for water seepage. Flashing provides the extra protection these spots need. These problem areas include the edges of skylights and chimneys, soil stacks, vent fans and roof valleys, as well as the intersection of the roof deck and dormer walls.
Most flashing is made of galvanized metal, but DIY'ers may prefer aluminum flashing because it's easier to bend. Most flashing products are designed for easy installation, and if the material is installed correctly, then your roof shouldn't leak. However, from time to time, the nails that fasten flashing work loose, or the flashing material pulls away from seams and joints and requires maintenance. Here's a look at some general principles of roof flashing that will help guide you through a proper repair or replacement—or even new construction.
A Look at Roof Design
All roofing systems are made of a number of different components: roof sheathing, underlayment, roofing material, roof intersections, flashing details and ventilation. Each of these systems must be installed correctly for the system to work as designed.
Common pitched roof systems rely on the force of gravity and the surface friction of the roofing materials to direct the flow of water downward and outward. These systems rely on overlapping elements—roofing felts, shingles, tiles and flashing details—to redirect the rainfall. The pitch of the roof provides the gravity and the detailing provides the redirection.
However, in low-slope roofing systems it is easier for water to accumulate. The force of gravity drives the water into every imperfection in the waterproofing system. So, for low-slope roofs, water is kept outside the building envelope by providing a perfect waterproofing barrier over the entire roof system and around every penetration in that roof.
Roof sheathing is attached to the roof framing, trusses or rafters, and provides the nail base for the other components of the roof system.
Next, roofing underlayment, often made of building paper or “felt,” is installed as the first weatherproofing layer for a pitched roof. Underlayment should be installed from the bottom of the pitched roof to the top, such that each upper layer overlaps the lower layer. This method of installation channels the water out and down, away from the wood-panel sheathing below.
Finally, roofing material, the visible finished layer on a roof, provides the primary waterproof barrier for the structure. For pitched roofs, almost all roofing materialsrely on some form of shingling to provide the weatherproof barrier. Like the underlayment, these roofs are installed from the bottom-up, with successive layers overlapping both vertically and horizontally to shed away water. Low-slope roofs can use many different proprietary and non-proprietary systems to form their waterproof barrier, from single to multiple-ply; adhered, mechanically anchored or ballusted; hot mopped or cold applied (solvent, urethane or epoxy-based).
Flashing works in conjunction with all of these elements to reinforce the waterproofing at roof intersections or penetrations.
A Closer Look at Flashing
For pitched roofs regardless of the application or type of flashing used, the purpose of flashing is to direct the flow of water that leaks into the intersection down and away from the interior of the structure to the topside of the roofing material. In every case, the top edge of the flashing passes underneath the underlayment, the upper pieces of flashing pass over the lower pieces, and the lower edge of the flashing always passes over the top of the roofing material. In such a manner, the flashing never directs the flow of water to the bottom side of the underlayment, never putting it in contact with the wood structural panel sheathing.
Valley flashing protects the valleys where two roof planes meet. This material is available with a V- or W-shaped profile and is placed over the top of the building felt before the roof's finishing material is installed.
Step flashing protects the joints between the roof deck and chimneys or dormers. Step flashing fits to each course of shingles and appears to “step” up the wall of the chimney.
Vent pipe flashing fits over flues or pipes. The shape of vent flashing is typically a cylinder with a wide flange at the base, which is lapped into the shingles as the roofing is installed.
Drip edges are strips of flashing material that run along roof eaves and rakes to prevent water from seeping under the finished roof along its edges.
The majority of roof leaks occur in locations where the plane of the roof is interrupted by a ridge, another roof intersecting at an angle, a wall or penetration. Even the simplest of rooflines has dozens of potential leaks sites due to chimneys, ridges, valleys, etc. Proper detailing around these areas, as detailed in the diagrams, is critical to prevent these leaks.
Metal flashing material is generally soldered or brazed. Similar towelding, the brazing process bonds two pieces of metal into one single piece. In many cases, flashing components have to wrap around corners or be spliced together, and in these cases they can be soldered or brazed to ensure a strong, durable joint.
Also, remember that both temperature and humidity can cause roofing materials (shingles, wood sheathing, flashing) to expand and contract with seasonal changes. The flashing materials will continue to be leak-proof if they can withstand this movement of the roofing materials. Well engineered and properly installed two-part flashing can handle this movement with no problem. Two-part flashing systems consist of a base flashing—often step-flashing—that is laced into the finished roof material. The base is then covered by another metal flashing piece lapped over it. The second piece should not be fastened to the base, so the two pieces can move against each other independently when the roofing materials shift with seasonal change.
Attention to Detail
Keep in mind that flashing details are a very technical aspect of roof construction, and this type of work is best left to experienced professionals. Soldering vertical surfaces requires skill, and you don't want to gamble with the integrity of your roof. The best way to learn proper flashing techniques is to spend time with an experienced craftsman as he installs a complete roof.
That being said, here are a couple of flashing tips that even an inexperienced homeowner should make note of. Always check the roof flashing and the condition of the shingles whenever you clean your gutters. Look for loose nails and any damage to the seals at the edges of the flashing. Roofing cement can dry out and crumble away, exposing joints to water. Fasten loose nails and cover exposed nail heads with roofing cement. Renew flashing seals by chipping out old caulking and mortar along the edges of the flashing. Recaulk the joints between the roof and the flashing. It's much easier to reseal the flashing than it is to patch a water-stained wall or ceiling.
Badly corroded flashing will need to be replaced. To do this, you will also have to remove several rows of shingles as well as the old flashing. Then replace and fasten the flashing, and reinstall the shingles with the proper overlapping procedure.
Also, new flashing can be exceptionally shiny, especially in contrast to the earthy brick walls of many homes. You may want to paint the flashing to match the roof. First use a stiff wire brush and solvent to clean the surface of any dirt, debris or corrosion (keep solvent away from asphalt shingles). Coat the flashing with a zinc-based primer followed by two or more coats of spray-on, rust-preventive metal paint.
Tip 4
Choosing A Contractor
Buying a new roof system is an important investment. Before you spend your money, spend time learning how to evaluate roofing contractors. You should insist on working with a professional roofing contractor. NRCA wants to assist you in getting the kind of results you expect—a quality roof system at a fair price. All roofing contractors are not alike, and NRCA recommends that you prequalify roofing contractors to get the job done right the first time.
The following guidelines will help you select a professional:
• Check for a permanent place of business, telephone number, tax identification number and, where applicable, a business license.
• Don't hesitate to ask a roofing contractor for proof of insurance. In fact, insist on seeing copies of his liability coverage and workers' compensation certificates. (U.S. workers' compensation laws vary by state. Consult your state's laws to determine workers' compensation insurance requirements.) Make sure the coverages are in effect through the duration of the job. Many building and home owners have been dragged into litigation involving uninsured roofing contractors. Also, if a contractor is not properly insured, you may be liable for accidents that occur on your property.
• Check to see if the roofing contractor is properly licensed or bonded. Some states have specific licensing requirements, and others do not. Your state's Department of Professional Regulation or Licensing Board will have this information.
• Make sure the contractor is financially stable. A professional roofing contractor can provide current financial information about his company.
• Look for a company with a proven track record that offers client references and a list of completed projects. Call these clients to find out whether they were satisfied.
• Insist on a detailed, written proposal and examine it for complete descriptions of the work and specifications, including approximate starting and completion dates and payment procedures.
• Have the contractor list the roofing manufacturers with which his firm is a licensed or approved applicator. Most roof systems require special application expertise to achieve lasting quality.
• Have the contractor explain his project supervision and quality-control procedures. Request the name of the person who will be in charge of your project, how many workers will be required and estimated completion time.
• Check to see if the contractor is a member of any regional or national industry associations, such as NRCA. Being a member of industry associations demonstrates a commitment to professionalism.
• Call your local Better Business Bureau or Department of Professional Regulation to check for possible complaints filed against the contractor.
• Carefully read and understand any roofing warranties offered, and watch for provisions that would void it.
• Choose a company committed to worker safety and education. Ask the contractor what type of safety training he provides for his workers and what industry education programs they have attended. The best roofing contractor is only as good as the workers who install the roof system.
• Keep a healthy skepticism about the lowest bid. If it sounds too good to be true, it probably is. Many fly-by-night contractors' below-cost bids seem attractive, but these contractors often are uninsured and perform substandard work. Remember, price is only one of the criteria for selecting a roofing contractor. Professionalism, experience and quality workmanship also should weigh heavily in your decision.
Commonly asked questions
Q: How can a home owner recognize when a roof system has problems?
A: All too often, roof system problems are discovered after leaking or other serious damage occurs. Periodic (twice-a-year) inspections often can uncover cracked, warped or missing shingles; loose seams and deteriorated flashings; excessive surface granules accumulating in the gutters or downspouts; and other visible signs of roof system problems. Indoors, look for cracked paint, discolored plasterboard and peeling wallpaper as signs of damaged roof areas.
Q: What are my options if I decide to reroof?
A: You have two basic options: You can choose a complete replacement of the roof system, involving a tear-off of your existing roof system, or re-cover the existing roof system, involving only the installation of a new roof system. If you've already had one re-cover installed on your original roof system, check with a professional roofing contractor. In many instances, building code requirements allow no more than one roof system re-cover before a complete replacement is necessary.
Q: My roof leaks. Do I need to have it replaced completely?
A: Not necessarily. Leaks can result from flashings that have come loose or a section of the roof system being damaged. A complete roof system failure, however, generally is irreversible and a result of improper installation or choice of materials or the roof system installation is inappropriate for the home or building.
Q: Can I do the work myself?
A: Most work should not be done yourself. Professional roofing contractors are trained to safely and efficiently repair or replace roof systems. You can damage your roof system by using improper roofing techniques and severely injure yourself by falling off or through the roof.
Maintenance performed by home and building owners should be confined to inspecting roof systems during the fall and spring to check for cracked or curling shingles and cleaning gutters filled with dead leaves and other debris. If you must inspect your roof system yourself, use a firmly braced or tied-off ladder equipped with rubber safety feet. Wear rubber-soled shoes and stay on the ladder (and off the roof system), if possible.
Q: How long can I expect my roof system to last?
A: Most new roof systems are designed to provide useful service for about 20 years. Some roof system types, such as slate, clay tile and certain metal (e.g., copper) systems, can last longer.
Actual roof system life span is determined by a number of factors, including local climatic and environmental conditions, proper building and roof system design, material quality and suitability, proper application and adequate roof maintenance.
Roofing product manufacturers offer a variety of warranties on their products. Take a close look at those warranties to see what responsibilities and financial obligations manufacturers will assume if their products fail to reach their expected lives.
Q: What will a new roof system cost?
A: The price of a new roof system varies widely, depending on such things as the materials selected, contractor doing the work, home or building, location of the home or building, local labor rates and time of year. To get a good idea of price for your roof system, get three or four proposals from reputable contractors in your area. Keep in mind that price is only one factor, and it must be balanced with the quality of the materials and workmanship.
For each roofing material, there are different grades and corresponding prices. There also are a variety of styles and shapes. You need to look at the full product range and make a choice based on your budget and needs.
Within the roofing profession, there are different levels of expertise and craftsmanship. Insist on a contractor who is committed to quality work.
Q: How can I determine my annual roofing cost?
A: When considering your roofing options, the following formula may help:
Total Cost (Materials and Labor) ÷ Life Expectancy of Roof System (in years) = Annual Roofing Cost
Asking the Right Questions is the Key to Selecting the Right Contractor. . .
To become a factory-certified GAF Master Elite™ roofing contractor, we had to show that we are:
•Fully Licensed- Fully licensed by our state to perform roofing work**
•Adequately Insured for your protection
•Have a Proven Reputation for providing quality roofing services throughout the community
•Committed to Ongoing Professional Training to ensure quality installation
Because of GAF’s stringent standards, only the top 3% of all roofing contractors have qualified as Master Elite™ contractors! Choosing a GAF Master Elite™ contractor is your assurance that you’ll be dealing with a quality, reputable, and dependable professional contractor — not some “fly-by-nighter.”
**Applies in areas where licensing is available.
Professional Installation
To ensure your total satisfaction, our company has been provided with extensive educational materials developed by GAF’s technical experts—allowing us to stay current in the latest roof installation techniques. That’s why GAF has authorized us to offer their enhanced system warranties, which even includes an option for a factory inspection of your finished roof!
Superior Protection
Most people think that a new roof is nothing more than just nailing up some shingles. We know better — so we recommend GAF’s Weather Stopper® 3-Part Roof Protection System. It gives you the best protection against a variety of all-too-common roofing problems. Plus, each component used in the system has earned the prestigious Good Housekeeping Seal!
“Worry-Free” And “Hassle-Free” Warranty Options
Because of our unique factory-certified status, the roofs we install are eligible for special warranties — all backed by GAF’s financial clout as North America’s largest roofing manufacturer. After all, a warranty is only as good as the manufacturer that stands behind it. With a GAF roof, you know that you will be covered throughout the warranty period—without fail! Ask us about which warranty option would be right for your home.
Your Safest Choice
Don’t trust your biggest asset to just any contractor. Factory-certified Master Elite™ contractors are your best and safest choice!
*Based on a survey of over 19,000 property owners served by GAF certified contractors over the last five years.
Tip 5
Without attic ventilation, heat and moisture build up in an attic area and combine to cause rafters and sheathing to rot, shingles to buckle, and insulation to lose its effectiveness.
Therefore, it is important never to block off sources of roof ventilation, such as louvers, ridge vents or soffit vents, even in winter. Proper attic ventilation will help prevent structural damage caused by moisture, increase roofing material life, reduce energy consumption and enhance the comfort level of the rooms below the attic.
In addition to the free flow of air, insulation plays a key role in proper attic ventilation. An ideal attic has:
• A gap-free layer of insulation on the attic floor to protect the house below from heat gain or loss.
• A vapor retarder under the insulation and next to the ceiling to stop moisture from rising into the attic.
• Enough open, vented spaces to allow air to pass in and out freely.
• A minimum of 1 inch between the insulation and roof sheathing.
The requirements for proper attic ventilation may vary greatly, depending on the part of the United States in which a home or building is located, as well as the structure's conditions, such as exposure to the sun, shade and atmospheric humidity. Nevertheless, the general ventilation formula is based on the length and width of the attic. NRCA recommends a minimum of 1 square foot of free vent area for each 150 square feet of attic floor—with vents placed proportionately at the eaves (e.g., soffits) and at or near the ridge.
Tip 6
Ice dams can be a persistent problem in regions with significant snow accumulations during extended periods of below-freezing temperatures. Ice dams form when roof areas become warm enough to melt snow, typically because of the combination of the insulating effect of heavy snow accumulation and heat loss from conditioned spaces. Water from melted snow runs down the roof under the snow cover and refreezes along roof overhangs where the roof surface temperature is lower. As more water from the melting snow becomes trapped behind the dam of ice, it can back up under shingles and infiltrate the underlayment, leading to leaks.
Melting snow that produces ice dams can be controlled if a roof surface temperature is maintained below freezing. To this end, NRCA recommends minimizing the amount of heat reaching the underside of the roof deck by adding a continuous ceiling air barrier or alternatively sealing interruptions in the ceiling vapor retarder with air-impermeable materials such as closed-cell spray polyurethane foam.
Secondly, a balanced attic ventilation system will help remove stray heat so temperatures throughout a roof deck are maintained close to the outside temperature. In areas with a history of ice dam formation, vent opening area and ventilation space height (in cathedral ceilings) should be appropriately sized to establish uniform rising air flow, which will cool a roof deck to below freezing when outside temperatures are below freezing. Guidelines for designing cathedral ceiling ventilation to prevent ice dam formation have been developed by researchers working at the Cold Regions Research Engineering Laboratory (CRREL) of the U.S. Army Corps of Engineers and are available by clicking here.
Measures that prevent stray interior heat from reaching a roof deck may not always be sufficient to prevent ice dam formation. Sometimes, ice dams occur even when attics are correctly insulated and ventilated because of solar heat and variation in snow cover thickness. A watertight barrier of self-adhering membrane underlayment or layers of underlayment felt cemented together with asphalt bitumen may be applied to a roof deck along the eaves as protection against ice dam leaks.
The 2009 IRC requires the installation of water and ice dam protection membrane in place of normal underlayment along the eaves as part of asphalt shingle roof systems in areas with a history of ice dam formation. The code requires the ice dam protection membrane extend at least 24 inches past the exterior wall line of a building.
NRCA recommends installation of water and ice dam protection membrane in locations where the average temperature for January is 30 F or less.
NRCA recommends water and ice dam protection membrane extends at least 24 inches past the exterior wall line of a building when installed on roof slopes of 4:12 and higher. For slopes less than 4:12 and in heavy snowfall regions, NRCA recommends water and ice dam protection membrane extends at least 36 inches past the exterior wall line.
