R New Roof Construction M A N U A L
INTRODUCTION New Roof Construction Manual Certi-labelTM Products Cedar shakes and shingles manufactured by members of the Cedar Shake & Shingle Bureau (”CSSB”) are the only products labeled with the ”Certi” brand name. Certi-label cedar shakes and shingles are made by experienced craftsmen who take pride in their trade and the quality of their product. Despite their varying sizes and sometimes remote locations, member mills are bound together by a rigid quality code.
CERTI-LABEL PRODUCTS CERTI-LABEL CEDAR SHAKES Certi-Split Handsplit Shakes CERTI-SPLIT PREMIUM GRADE 100% Edge Grain Handsplit Red Cedar Shakes CEDAR SHAKE & SHINGLE BUREAU THE RECOGNIZED AUTHORITY SINCE 1915 SUMAS, WASHINGTON (604) 820-7700 These shakes have split faces and sawn backs. Cedar logs are first cut into desired lengths. Blanks or boards of proper thickness are split and then run diagonally through a bandsaw to produce two tapered shakes from each blank.
CERTI-LABEL PRODUCTS 2 CERTI-GUARD R CERTI-GUARD R Pressure-Impregnated Treated Products Certi-label products can also be treated. Products are available either fire-retardant-treated OR preservative-treated. Special care must be taken to follow the treatment company’s recommended installation instructions.
GENERAL DESIGN AND APPLICATION DETAILS Sheathing Shakes and shingles may be applied over spaced sheathing. Spaced sheathing is usually 1 x 4 or 1 x 6 softwood boards and shall not be less than 1 x 4 boards. Solid sheathing is recommended for shakes and may be required in seismic regions or under treated shakes and shingles. Solid sheathing is used in areas with wind-driven snow. Please note that the only solid sheet sheathing tested with Certi-label shakes and shingles is plywood.
GENERAL DESIGN AND APPLICATION DETAILS 4 Certi-label Shakes A solid deck is recommended in seismic activity, hurricane and tornado regions and in areas where wind-driven snow is encountered. Roofing felt system interlay between the shake courses is required whether the sheathing is spaced or solid. The felt interlay acts as a baffle that prevents wind-driven snow or other foreign material from entering the attic cavity during extreme weather conditions.
GENERAL DESIGN AND APPLICATION DETAILS Certi-label Shingles There are two acceptable methods for application of spaced sheathing: One is to space 1 x 4 boards to coincide with the weather exposure (Table 2, Page 20) of the shingles (Figure 5). Thus, if the shingles are to be laid at 5 1/2" to the weather, the sheathing boards would also be spaced at 5 1/2" on center. In this method of application each shingle is nailed to the center of the 1 x 4 board.
6 MANSARD ROOF DETAILS The mansard is particularly well suited to renovation work on pitched roof houses because the upper story can be enlarged without adding extra height to the structure. The low downward slope of the mansard roof line acts visually to reduce the scale of a building and helps to eliminate a boxy appearance. This technique is used frequently on large commercial projects, particularly those near residential neighborhoods.
LOW SLOPE ROOF DETAILS, HIP AND RIDGE DETAILS The minimum roof slope on which Certi-label shakes are recommended is 4:12 and for Certi-label shingles, 3:12. It is possible, however, to apply Certi-label shakes or shingles successfully to solid sheathed roofs of lower slope providing a special method of application is followed (such as Figure 7), however shingles must be applied at a reduced exposure (page 20). Never interlay shingles with felt.
ROOF JUNCTURE DETAILS 8 Correct construction of roof junctures and slope transitions is vital to ensure the integrity of the roof system. In the following cases, where metal flashing is employed, it should be no less than 26 gauge galvanized steel or acceptable equivalent. Check with your local building official for their preference in your area. It should be painted on both sides with a good metal or bituminous paint.
ROOF JUNCTURE DETAILS 9 Apex Juncture On this roof juncture (Figure 11) metal flashing should cover the top 8" of the roof and the top 4" of the wall. It should be installed before the final course of Certi-label shakes or shingles is applied to the wall. The recommended sequence of application is to apply Certi-label shakes or shingles first to the wall then to the roof. The overhanging roof material is then trimmed flush with the wall.
ROOF VALLEY FLASHING DETAILS 10 Valleys: Certi-label Shingles For roofs with slopes of 12:12 or greater, valley flashing should extend not less than 8" on each side of the valley centerline. For roof slopes less than 12:12, flashing should extend not less than 11” each side. Valley metal should be underlayed with No. 30 ASTM D226 Type II or No. 30 ASTM D4869 Type IV roofing felt.
ROOF PROJECTION FLASHING DETAILS Top, head, saddle, pan or cricket flashing 11 Step flashing interwoven with each course Counter flashing Step flashing 3" laps Certi-label product Bottom apron flashing Bottom apron flashing Figure 14a: Skylight Flashing Figure 14b: Skylight Installation Certi-label product 3" minimum 6" minimum Bottom or Apron flashing Head flashing Typical chimney flashing not requiring soldering Step flashing 3" minimum overlap Caulking Caulking Recommended step flashing wid
ROOF FASTENER GUIDELINES 12 Nails Do not use electro galvanized (EG) fasteners. Each Certi-label shake or shingle shall be applied with two fasteners. Nails must be stainless steel Type 316 in locations within fifteen (15) miles of salt water. For locations outside the salt water zone - nails must be stainless steel, Type 304, Type 316, or hotdipped galvanized with a coating weight of ASTM A 153 Class D (1.0 oz/ft2). Stainless steel nails offer the highest degree of corrosion resistance.
VENTILATION DETAILS Ventilation Guidelines The importance of good attic ventilation beneath the roof cannot be overemphasized. Such movement of air will prevent or inhibit condensation of moisture on the undersurface of the Certi-label shakes or shingles, or on the roof decks. Vents should be provided at the soffits (eaves) as well as at gable ends (screened to prevent ingress of insects), on roof by using attic roof ventilation or preferably the ridge lines with cross-ventilation desirable.
14 VENTILATION DETAILS Ridge Vents The amount of venting depends upon the size of the roof, roof design/structure, (attic present or not, etc.) as well as local climatic conditions. Check with your local building official for requirements in your area. One rule of thumb for venting the attic area is 1 square foot per 150 square feet of floor area. One half of this (1/2 square foot per 75 square feet of floor area) amount should be in the soffit or eave and one half (75 square feet) in the roof system.
SPECIALTY ROOF DECK DETAILS Certi-label shakes or shingles (applied per specification) Boards Rigid insulation Wood Deck Wood decks form an ideal base over which to apply Certi-label shakes or shingles, since they can be attached in the conventional manner. Wooden deck Rigid insulation raises the issue of how to fasten Certi-label shakes or shingles. The use of abnormally long nails driven through the Certigrade shingles, the insulation and into the deck below is generally unsatisfactory.
SPECIALTY ROOF DECK DETAILS 16 Rigid Insulation Numerous types of rigid insulation are now in use, and may be made from expanded polystyrene beads, rigid urethane laminate, low density fiberboard, or from fast-setting liquids poured on-site. They vary in thickness up to more than 2" and in length and width depending upon the manufacturer. All these types are efficient insulators and are usually of sufficient density to hold the weight of a normal roofing material without the need for lumber bridging.
COLD ROOF SYSTEM DETAILS Certi-label shakes and shingles are an excellent roofing material for cold weather areas that experience heavy snowfall and severe temperature extremes. Certi-label shakes and shingles offer the advantages of durability, superior wind resistance and good thermal and acoustical properties. As with any other roofing material, however, their best performance depends upon proper design, sound construction practice and correct installation. Design, of course, is very important.
18 COLD ROOF SYSTEM DETAILS Wide overhangs at the eaves should be avoided as they provide large cold areas for snow and ice build-up. A strip of metal along the eaves helps shed ice quickly. Sliding ice and snow are constant hazards and should be given primary consideration in the total building design. Outside doors should not be located at the bottom of a roof slope. Entrances and all pedestrian traffic areas are better situated beneath the gable ends of the roof.
SOLID DECK APPLICATION/HIGH HUMIDITY AREA DETAILS In areas of high humidity where solid sheathing is required: Two nails (only) for each shake approximately 3/4" from edge and approximately 1 1/2" above exposure line. Space shakes 3/8" to 5/8" apart Following are 4 different suggested methods of application to increase longevity: 19 The bottom edge of the felt should be positioned above the butt of the shake at a distance equal to twice the weather exposure. Never interlay shingles with felt.
COVERAGE AND EXPOSURE TABLES 20 Shingle Coverage Table 1 LENGTH AND THICKNESS 16" x 5/2" 18" x 5/2 1/4" 24" x 4/2" Approximate coverage of one square (4 bundles) of shingles based on following weather exposures 3 1/2" 70 4" 80 72 1/2 4 1/2" 90 81 1/2 5" 100* 90 1/2 5 1/2" 6" 6 1/2" 7" 7 1/2" 100* 73 1/2 80 86 1/2 93 100* NOTE: * Maximum exposure recommended for roofs.
CEDAR CARE AND MAINTENANCE OVERVIEW Please Note: ONLY experienced professionals who follow proper safety and workmanship practices should implement the information contained herein. • Overhanging branches should be kept trimmed away from the roof. This will prevent leaves, small branches and other debris from building up and keeping the roof wet. Certi-label Cedar Is Naturally Long-Lasting • Gutters and downspouts need to be cleaned regularly, usually in the spring and fall.
22 CEDAR CARE AND MAINTENANCE OVERVIEW Topical Treatment Products Powerwashing It is not within the Cedar Bureau's mandate to recommend brand names of topical roof treatment products. Consult with your local professionals for product information regarding cleaning and preserving cedar in your area. The Cedar Bureau does, however, recommend the following: This is the most controversial issue in the care and maintenance industry.
SPECIFICATION GUIDELINES This information has been designed to aid 8. All solid sheathing shall be lumber or architects, consultants and builders in structural panels applied according to specifying Certi-label shakes and shingles. It specifications of the American Plywood suggests a standardized terminology and style Association. Please note: the only solid for ordering in the hope of improving sheet sheathing tested with shakes and accuracy. It incorporates a general outline of shingles is plywood.
SPECIFICATION GUIDELINES 24 17. Where saddles or crickets are formed in back of chimneys, curves or similar vertical surfaces, they shall be carried not less than 10" under the Certi-label shakes/shingles. 18. Step flashing shall be used where vertical surfaces occur in connection with slopes. They shall be formed of separate pieces. Flashing shall extend horizontally not less than 3" and up the vertical wall so that they shall be lapped by the counter flashing not less than 4".
HOW TO READ A CERTI-LABEL © 2015 2 004 1 1 NUMBER 1 25 9 GRADE Handsplit Red Cedar Shakes 3 4 CEDAR SHAKE & SHINGLE BUREAU THE RECOGNIZED AUTHORITY SINCE 1915 SUMAS, WASHINGTON (604) 820-7700 Quality Control Agency Logo Building Code Standards R 5 Mill Quality Certification Number Label ID Number Litho in Canada 6 www.cedarbureau.org 10 Product Testing Numbers 11 Country of Manufacture 12 Mill Name 13 Mill Location Mill Phone Number 7 8 1. 2. 3. 4. 5.
R Contact us for more information: US Address PO Box 1178 Sumas, WA 98295-1178 Canadian Address #2 – 7101 Horne St. Mission, BC V2V 7A2 TEL: 604-820-7700 FAX: 604-820-0266 www.cedarbureau.org info@cedarbureau.com This manual shows Cedar Shake & Shingle Bureau recommended procedures as of the manual’s print date. It is advisable to contact the Cedar Shake & Shingle Bureau to ensure that you are using the latest available information.
