For roofs located where the basic wind speed per Figure R Asphalt shingles can be installed on roof slopes of to if special procedures are followed for underlayment. Eaves flashing to a point at least 24 inches inside the interior wall is recommended if there is any possibility of ice dams or water backup from leaves or pine needles. A conservative approach is to run self-adhering bituminous membrane over the entire low slope area.
Once the underlayment is complete, shingles are installed in the standard fashion. In cold weather, manual sealing may be required as wind uplift will be greater on shallow roofs. Asphalt shingles should not be installed on vertical walls , but they can be used on steep slopes, such as mansard-style roofs. For best performance, use the six-fasteners-per-shingle method Figure above and manually seal the shingles with plastic roofing cement see manual sealing discussed.
Our steep roof photo left shows quite a few shingles lost from this rather steep church roof slope. Similar problems occur when asphalt shingles are nailed to the steep sides of mansard roofs unless proper nailing and sealing have been performed.
We discuss the recommended installation details for installing asphalt roof shingles on very steep or near vertical roof slopes and also use of roof shingles or even roll roofing on vertical building walls separately.
Flashings for asphalt shingles should be corrosion resistant metal with a minimum thickness of 0. A cricket or saddle should be installed on any chimney greater than 30 inches wide and can be covered with flashing or the same materials used as a roof covering. The roof deck should be sound and level before laying the underlayment. Fifteen-pound or heavier felt underlayment is required by code in some areas.
Whether or not it is required, underlayment is cheap insurance against problems. There are several good reasons to install underlayment:. Details about the requirements and benefits of roofing underlayments are at these articles:. On roofs with a slope of or greater, use a single layer of 15 lb. Vertical joints should lap a minimum of 4 inches and be offset by at least 6 feet in successive rows see Figure at left.
Secure each shingle course along seams and edges with enough corrosion-resistant nails to hold it in place until the roofing is installed. For best protection against leaks, run felt 6 inches over ridges and hips, from each direction, and 6 inches up any adjoining walls. Valleys should be lined with a full width of roofing felt or bituminous membrane pushed tight into the valley so there is no slack.
Side courses of underlayment should run over the valley lining and extend 6 inches past its edge. Asphalt shingles can be used on roofs with a slope of to if double-coverage underlayment is used. Start with a inch strip of 15 lb. Wherever there is a possibility of ice or snow buildup or the backup of water from leaves or pine needles, install a self-adhering bituminous membrane along the eaves that extends up the roof to a point at least 36 inches inside the interior wall line.
An alternative approach, not widely used anymore, is to seal all laps in the lower courses of roofing felt with lap cement or asphalt plastic cement.
In areas with extensive snowfall or windblown rain, the best protection against leakage is to cover the entire low-slope roof area with a bituminous membrane, as shown in Figure If the roof changes to a steeper slope, for example, where a shed dormer joins the main roof, extend the membrane 12 to 18 inches up the main roof slope.
Bituminous membranes are self-healing around nail holes, and because they bond fully to the sheathing, any leaks that occur cannot spread. As a safeguard against expensive callbacks, many roofers now apply membrane to the entire surface of any roof with a slope of or less. Where a cold roof cannot be achieved due to complex roof shapes, unvented roofs, or retrofit constraints, ice dams may form during severe winters, in some cases, causing pooled water to wet wall cavities and interior finishes.
Where adequate insulation and ventilation cannot be assured, self-adhering bituminous eaves flashing should be installed. The membrane should go from the lower edge of the roof to a point at least 24 inches inside the interior wall line Figure at left. Where two lengths of eaves flashing meet at a valley, run each across the valley, starting with the length from the roof with the lower slope or lesser height.
The valley flashing should later lap over the eaves flashing. For full protection, some contractors extend the eaves membrane up to the bottom of any skylights and continue it around the sides and top of the skylight. By wrapping the skylight curb with membrane as well, any potential flashing leaks are also eliminated as shown in Figure at left. If it is impractical to install membrane all the way from eaves to skylight, install a 3-foot-wide band of membrane below the skylight, lapping the bottom edge of the membrane over the row of shingles where the membrane terminates.
Drip Edge. Drip edge should always be used along the eaves to kick water away from the fascia, and it is a good idea along rakes as well. Drip edge should lap over the underlayment at the rakes and under it at the eaves as shown in Figure at left.
Overlap joints in the drip edge by 2 inches. Some manufacturers of eaves membranes specify that the drip edge be installed on top of the membrane along the eaves, violating the principle that upper layers of flashing should overlap lower layers. To remedy the problem, the manufacturers suggest using a second strip of membrane to seal the top of the drip edge to the eaves membrane.
In practice, however, most installers place the drip edge first and lap the eaves membrane over it, consistent with good building practice. Is anyone familiar with this type of roofing installation? We could be wrong, but it seems as if the rows are too far apart?
We would be very grateful for any information or insights. Thanks in advance! It looks as if there was a deliberate effort to expose a black shadow-line between courses.
I can't know if this is a shingle appearance feature or if the roofer separated the courses by more space than the usual " of asphalt shingle exposure. Make some measurements and tell us the shingle exposure amount: that is, the distance from the lower edge of a course of shingle tabs down to the lower edge of the successive course below.
On by mod - When were colored plastic capped roofing nails introduced? David Thank you for pointing out an area where we can add some historical detail on roofing nails. A general answer is in the U. Plastic-capped roofing nails are also referred to as roofing nails that incorporate a "pressure plate", generally used to hold underlayment such as felt in place on the roof deck. Pressure plates around roofing nails have been in use for nearly years, though the plates were traditionally made of metal.
So we took a look at more-recent roofing nail patents where plastic pressure plates are described. Those are much more recent. The earliest relevant U. Patent 2,,, issued July 21, Plastic roofing nail plates or roofing nails with plastic caps: Bruins, Roger C. Patent 5,,, issued April 18, Excerpt: A resilient molded pressure plate formed of polypropylene or the like is provided for a roofing nail in engagement with a sheet of roofing felt to increase the retention of the felt. With over 60 years of combined experience, Bumble Roofing provides easy, friendly services to structures including residential, commercial, industrial, multi-family, and government buildings along with hospitals, hotels, and churches.
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Thinking about some major home renovations? When it comes to something like painting or patching, the average DIY enthusiast is more than capable of tackling the task. Even tougher tasks, like flooring installation, can be a reasonable project if you know your way around a toolbox. Roofing is an extremely tall order, though.
To install roofing, first you'll need to install a starter strip, which is just a backing for the first visible row of shingles. Then, starting at the lower-left corner and working your way up and to the right, install the shingles. You'll want to stagger the gaps so water can't get into the roof sheathing by cutting progressively larger amounts from the first shingle in each row.
So, you'll cut nothing off the first row, 6 inches off the second row, 12 inches off the third row, and so on. For more expert roofing advice, check out the full article below! Did this summary help you? Yes No. Log in Social login does not work in incognito and private browsers. Please log in with your username or email to continue.
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Look up your local laws regarding roof installation and rehab. Contact your local building department or look their codes up online to see what the process for this looks like where you live. Apply for the necessary building permits if required. Contact your local building department or look their codes up online to see what the process for this is where you live. If your roof is bigger than 1, square feet 93 m 2 , you will likely to need to pay more and file for additional permits.
Measure the size of your roof. If possible, pull up the architectural plans for your home to make this easy. These plans will give you all of the measurements you need.
For each portion of the roof, multiply the length and width together to find the area. Add your areas together. You may be better off simply estimating the size of each section and then ordering a little extra so that you have plenty of material to cover the entire roof.
Choose between asphalt shingles and membrane roofing. There are only two realistic options for DIY roof installation when it comes to the material. Order your materials and purchase any necessary tools.
Most big box home improvement stores will ship roofing materials, but you can order them from a wholesale supplier or roofing contractor as well. Take the proper safety precautions.
If your roof is angled at all, you must purchase and install a personal fall arrest system. The instructions will come with the system you buy, but it generally involves installing an anchor in the roof, and then attaching a reinforced lifeline to a harness.
Without one of these, you cannot work on the roof. Method 2. Mark the location for the drip edge with a pencil and chalk. Fire-resistance classification requirements are based on the type of construction and the building use group. Most other roof system requirements in the building codes i. The building code designates the type of construction based on size and occupancy i. Certain buildings are required to have a minimum level of fire resistance based on the occupancy and use of the building.
It is important to know the building code that is adopted in the jurisdiction having authority. While not all jurisdictions require a permit for roofing work, repairs or replacements will need to comply with the applicable code in effect at the time of the repairs or replacement. Similarly, the building code that was in place at the time of the original construction or when the roof cover was last replaced should be known in order to verify compliance of the roof cover.
Users should contact the authority having jurisdiction if there are questions. Qualified building officials and building envelope specialists are both useful contacts to help determine local area requirements and if new-to-market products are acceptable.
The addition of an extra layer of roof cover or the change of a light weight roof cover to a heavier one will result in an increase in the dead load on the roof structure. The roof structure should be assessed and verified to determine if it will be able to support this additional weight plus the construction and live loads e.
A roof recover or overlay is the process of installing a new roof covering over an existing roof covering. A roof replacement is the process where all existing layers of roof covering are completely removed down to the roof deck before a new roof covering is installed.
During roof repairs or replacement, the condition of the roof deck and framing must be documented. The new roof covering must not be installed on damaged structural roof components.
Similarly, if a roof is recovered, the existing roof covering layer must be in good condition to support the new covering. Contact an engineer or design professional for more information. Building codes may provide specific instructions and limitations for conditions when recovering is permitted and when replacement is required. Note: Not all jurisdictions will allow the installation of a new roof covering over an existing roof covering.
Building codes may require an evaluation of the decking and roof-to-wall connections when a substantial portion of the roofing materials are removed from the roof diaphragm of a building located in a high or special wind region. There are no specific requirements for hail resistance of roofing products in model building codes.
In moderate hail zones, recover of an existing roof is often not permitted please refer to the jurisdiction having authority. Many manufacturers have some of their roofing products and assemblies tested using standards such as UL and FM , but many products are unrated for impact resistance as it pertains to hail performance. Roof coverings and assemblies must be capable of resisting the required wind loads for the location in which the building is located. Design wind speeds are much higher along coastal areas of the hurricane-prone regions, but are much lower over the majority of the U.
Compliance with wind loading requirements in the building code will require a roof system to be tested and designed to meet the applicable wind speeds and the associated uplift pressures. Design wind speeds are provided by the adopted building code, and are assigned based on the location and risk category of the building.
Design wind speeds for particular buildings are determined from maps included in the locally adopted and enforced building codes. The design wind speed is used directly in the selection of roofing products and their installation specifications. For More Information: Maps used to establish design wind speeds and the definitions of wind speeds used in the maps have changed over the years. Early maps used what is called the fastest-mile wind speed as the reference standard design wind speed.
Beginning with the edition of ASCE 7, the design wind speed basis was changed to a 3-second gust wind speed, which is different than the 1-minute average speed used in the Saffir-Simpson Scale for hurricanes. An existing roof should be evaluated based on design wind speeds and uplift loads that were in place at the time of permitting, and it is important to recognize the difference in the definition of the reference speeds. Generally, design wind speed maps from ASCE 7 are adopted into the model building codes during the next update cycle.
Once the model building codes have been updated, the updates will begin to make their way into locally adopted codes and standards.
Buildings located in areas with closely spaced surface obstacles, such as trees and buildings that slow down the wind near the surface of the earth 2 typically experience wind forces of lesser magnitude than those with fewer terrain irregularities 3. The exposure category may vary for a certain building depending on the terrain in a given upwind direction.
For example, a building located in a coastal, urban environment will have one exposure for wind coming from the ocean side and another for wind coming from the city side.
In these instances, the exposure category resulting in higher wind forces will generally be selected for design. Variations in wind loads with wind exposure category are incorporated in ASCE 7 as part of the velocity pressure exposure coefficients.
The default category applies if the site does not fit other exposure definitions. Roof design wind loads are the wind pressures and resulting uplift forces for which the roof structure is designed. This includes structural components such as roof sheathing or rafters, or roof cover components and the connections of these elements. These loads are calculated based on the criteria from ASCE 7. Equations for wind loads on roof systems are based on several variables, including:. ASCE 7 provides the procedures needed to calculate design wind pressures for the components and systems outlined above.
It also contains tables listing design pressures for buildings up to feet in height based on some simplifying conservative assumptions.
The IRC contains tables of design pressures for buildings with heights below 60 feet. Both sets of tables include roof design pressures suitable for design of the elements identified above. The ASCE 7 calculation procedures and the tables of design pressures are not reproduced here; please refer directly to ASCE 7 to obtain that information.
Research has demonstrated reductions in wind loads for roof covers, such as asphalt shingles and roofing tiles, where the capacity for pressure equalization has been demonstrated. Consequently, building codes allow different approaches for determining design wind loads for these systems.
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