Wood shingles and wood shakes are created with the use of redwood, pine, cypress, and red cedar trees. These shakes are split from logs and manufacturers had them reshaped for use commercially. These can be thicker at the end of the butt compared to shingles. Generally, one or two surfaces may get split so you can have an effect that appears textured. A shake that got re-sawed and split has a face that appears sawed and split. The taper sawed shake gets naturally tapered and sawed on both of its sides. Wood shingles get sawed on both of its sides with a uniform thickness and even taper. Whenever it gets applied to shingles, it is termed by the industry as “Royal” and “Perfection” with lengths of 24 and 18 inches respectively. Cedar shingles and cedar shakes that are treated with pressure are available. These have chemical preservatives and fire retardants allow an increase in resistance to fire to avoid premature decay and rot in specific climates.
Pine shakes that are created with the use of the southern yellow pine got sawed by taper. Also available are those that are treated with pressure and preservatives as protection against insects and decay. For pine shakes, they are required to have interlayment felts.
Deck of the Roof
It can be possible for wood roof systems to get applied over a skipped or spaced sheathing or wood decking that is closely or continuously spaced. Whenever a solid roof sheathing or decking is used in the roof deck, it is required to have a membrane of protection that is made of an ice dam.
Included in the highly common materials that people use for the roof decks are plywood as well as the oriented strand board. Whenever people use plywood, the NRCA is recommending the use of a 1/2 inch or a minimum of 15/32 thick exterior-grade normal plywood for rafter spacings of 16 inches. When it comes to rafter spacings of 24 inches, it is recommended to have a nominal thickness of 5/8 of an inch. NRCA is recommending a minimum of 1/2 inch or 15/32 inch nominal OSB of exterior-grade for rafter spacings of 16 inches.
Exercising caution is essential whenever the roof decks get constructed with the use of these materials:
Wood Treated with Fire-Retardant
It is essential to consider the use of wood panel decks treated with fire-retardant carefully as its service’s heat history may cause the premature activation of fire retardants due to the deterioration of specific wood panels that are treated with fire retardants.
OSB or Oriented Strand Board
NRCA has concerns with regards to the potential problems that are fastener holding as well as dimensional stability due to moisture’s effects wherever nonveneer products such as the OSB are used as the decking of the roof.
Wood Treated with Preservatives
Lots of manufacturers of roofing materials recommend the construction of wood roof decks with wood that is treated with klin or air-dried lumber that is non-treated or pressure treatment with non-oil preservative.
Interlayment and Underlayment
Organic felts which are non-perforated and saturated with asphalt may be among the underlayments that are commonly used for wood shingles and wood shakes. These are often designated as Type 30 and Type 15 which reflect a designation of weight that is once utilized a pound for every square. Since No. 30 and No. 15 are no longer available, people now utilize Type I and II.
Whenever the “felt paper” or underlayment gets specified, non-perforated and asphalt-saturated felt must get applied to shingle fashion on roof decks that have a slope of 18 degrees of 4:12 or more. It is not recommended by the NRCA to utilize wood shingles or wood shakes that have a slope that is less than 18 degrees or 4:12.
Whenever wood shakes are involved, the produced sheets have widths of 450 mm or 18 inches as “interlayment felts.” Instead of having these applied over a substrate directly, these are placed in between the wood shakes’ courses.
In places wherein a maximum of 30º F is the average temperature, it is recommended by the NRCA to install a membrane of protection made of ice-dam. Generally, this protection membrane made of ice-dam is a bitumen membrane that is modified with polymer that is also self adhering.
The membrane of protection made of ice dam needs to get applied beginning at the eaves of the roof and extending up the slope from the building’s exterior wall line with a minimum of 24 inches. Whenever the slopes are less than 18 degrees or 4:12, it is recommended by the NRCA to have 36 inches as a minimum.
Fasteners
It can be possible for wood roofing to become attached to the roof deck with non-corroding metallic staples or galvanized and non-corroding stainless steel or steel nails. It is essential to use a minimum of a couple of fasteners to every shingle and shake. The nails have to become long enough so it can extend through the roof deck’s underside or penetrate through a minimum of 3/4 of an inch of any layer of roofing material such as wood board decks or planks.
Flashings
Wood systems such as flashings may fall into the following categories: vertical surfaces, valleys, penetrations, and perimeter edge metal.
- Vertical Surfaces – Whenever the roof system’s surface is vertical, here are the four kinds of flashing that are commonly used: backer or cricket, step, apron, and counter-flashing.
- Valleys – These are often referred to as “open valleys” and they are lined typically with sheet metal.
- Penetrations – These exhaust pipes, vents and plumbing soil stacks are flashed into the systems of the wood roof with specific types having a some kind of flat flange that is installed underneath the flange’s up-slope shingles and extends around the penetration.
- Metal of Perimeter Edge – The consideration of using perimeter edge metal may depend on the cycle of freeze-thaw, anticipated rainfall, and the climate’s severity.
It is required by cricket, step, and apron flashings to have counterflashing in some form to protect and cover the top edges from the intrusion of water. There are numerous cases wherein the wall cladding or covering material acts as a counterflashing. Whenever this does not happen, it is important to install a metal counterflashing that is mounted to the surface vertically.
Standards in the Material
When it comes to which shingle or shake products and from what manufacturer people must use, NRCA is not making any recommendations. There are no standards in ASTM when it comes to wood roof covering but there are standards when it comes to grading. The CSSB or Cedar Shake and Shingle Bureau Standard called CSSB-97 has rules in grading for wood shingles and wood shakes. It is recommended by the NRCA for the cedar shingles and cedar shakes to have a minimum grade of No. 1 that requires no defects in face, clear heartwood, and a 100% edge grain.
Warranties
Whenever you want to buy a new system for your roof, you need to take two warranties in consideration. The first one is the warranty of the manufacturer. Generally, manufacturers have warranties that cover any failures in the product of the roof covering. Make sure to review the bulletin on consumer advisory of the NRCA to get additional information that addresses warranties in roofing. After the completion of the project, it is essential for the contractor to provide a certificate of the records.
Next, the contractor for roofing must give you a warranty that covers his workmanship. Ideally, this must cover issues related to installation. The warranty needs to include the items covered as well as what can make them void. Lots of contractors offer coverage for a year or two but there is no standard in the industry as of the moment.
At Orezona Building & Roofing Co., you’ll get a team of contractors that have more than two decades of combined experience and treat every project like it is their own. The company is dedicated to provide excellent customer service and customer satisfaction. Aside from that, we always make sure that our prices are always honest and fair.
Whenever you are in need of roofing services in Corvallis OR, make sure to contact us.