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This article discusses best construction practices for wood shingle wall siding installation, including wood shingle types, grades, nailing requirements, application patterns, coatings & stains. This article series discusses best practices construction details for building exteriors, including water and air barriers, building flashing products & installation, wood siding material choices & installation, vinyl siding, stucco exteriors, building trim, exterior caulks and sealants, exterior building adhesives, and choices and application of exterior finishes on buildings: paints, stains. This article series includes excerpts or adaptations from Best Practices Guide to Residential Construction, by Steven Bliss, courtesy of Wiley & Sons.

© Copyright 2012 InspectAPedia.com, Daniel Friedman, Steve Bliss, Wiley & Sons, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website.

Wood Siding Shingles and Shakes: Grades, Installation Details

Adapted/paraphrased with permission from Best Practices Guide to Residential Construction. Steven Bliss.

Cedar shingles and shakes are a popular choice for sidewall applications in coastal regions. Eastern white cedar shingles are often left unpainted in New England coastal areas. Red cedar shakes are often left unpainted on the West Coast. Red cedar shingles are sometimes left natural, but more often are painted or stained. Our wood shingled home photographs here demonstrate red cedar shingles exposed in two different exposure lengths, an aesthetic choice made by our associate Paul Galow. Sidewall installation is similar for shakes and shingles with some variation in exposure (see Table 1-5).

Grades of Wood Shingles Used on Building Walls

Red cedar shingles come in four grades, but most sidewalls use grades No. 1 or No. 2. No. 1 is all heartwood and all edge-grain wood.

Red cedar shingles are available rebutted and rejointed (R&R) where a uniform appearance is desired and machine grooved for a textured surface. Red cedar shakes come either taper-split or untapered and are usually installed in Premium or No. 1 grade (see Table 1-6).

Eastern white cedar shingles are available in four grades. Most sidewall work on building exteriors uses Grade A (Extra), which is all clear heartwood, or Grade B (Clear), which has no knots on the exposed face (see Table 1-7).

Installation Details for Wood Shingles on Walls

The simplest and most common pattern for sidewall shingles and shakes is single coursing. For wider exposures and deeper shadow lines, shingles and shakes can also be installed in double courses. A rustic staggered pattern is also possible.

Underlayment Requirements for Wood Shingles

The Cedar Shake and Shingle Bureau recommends installation over Type 30 asphalt felt underlayment for red cedar shingles and shakes. Install the felt paper with minimum 6-inch overlaps on vertical joints, 2 inches on horizontal laps, and 4 inches wrapped each way at inside and outside corners. Creasing the felt at corners will help achieve a tight fitting corner.

For optimal performance, manufacturers of Eastern white cedar shingles now recommend installation over horizontal furring spaced equal to the shingle exposure or over a ventilating layer such as Benjamin Obdyke’s Home Slicker®. They acknowledge that most sidewall installations still go directly over the wall sheathing covered with felt paper or plastic housewrap. Field experience suggests that an air space or drainage/ventilation layer is critical for longevity on roofs, but on sidewalls, good quality white cedar shingles perform adequately without these extra steps.

Wood Shingle Single-Coursing Installation Details for Walls

The first course of shakes or shingles is doubled, with the outer course dropped 1/2 inch lower to create a drip edge (see Figure 1-14, at left). Tack up a length of 1x3 furring as a guide for the next course, moving up the wall with each successive course. To create a weather-tight exterior, do not exceed the exposures shown in Table 1-5 above. Red Cedar Wall Shingles: Space No. 1 red cedar shingles 1/8 to 1/4 inch apart to prevent possible buckling. A 1/4-inch space is recommended for No. 2 R R& R red cedar shingles.

White cedar shingles should be spaced from 1/16 to inch apart depending on conditions — a 1/16 -inch gap would be appropriate for green shingles, which are prone to shrinkage, and a 1/4-inch gap for kiln-dried shingles installed in a moist environment. Also, offset joints in successive shake or shingle courses by at least 1 1/2 inches as shown in Figure 1-15. Treat knots and other defects like an edge and offset adjacent courses at least 1 1/2 inches. With white cedar shingles, also make sure that two joints do not align if separated by only one course.

Wood Wall Shingle Double-Coursing Installation Details

For increased exposures and deeper shadow lines with red cedar shingles or shakes, apply in double courses, as shown (Figure 1-16). Despite the greater exposures, considerably more material and labor are required. Installation of wood shingles on a building wall starts at the bottom with a triple layer and succeeding layers are doubled as shown.

Nailing Details for Wood Shingles

Use corrosion-resistant box or casing nails of either stainless steel, hot-dipped galvanized, brass, or aluminum. For concealed nails, hot-dipped galvanized are adequate. For exposed nails at corners and under eaves and windows, stainless steel, brass, or aluminum are less likely to stain the wood.

For red cedar shingles and shakes, nail 2 inches above the butt line and 3/4 inch in from each end. Cedar shingles wider than 10 inches need two additional nails driven 1 inch apart near the center of the shingle. Nails should fully penetrate the sheathing (see Table 1-8 below). Aluminum or stainless-steel staples with 7/16-inch to 3/4 -inch crowns are also an option for red cedar shingles if accepted by local codes.

White cedar shingles are nailed 1-1/2 inch above the butt line and 3/4 inch in from each end. Manufacturers recommend a 1-1/4 inch (3d) box or shingle nail for new construction and a 1-3/4 inch (5d) nail when going over another siding material. Drive nails flush with the surface. Do not overdrive and set the nails or leave them projecting from the surface.

Wood Wall Shingle Clearance at Flashings

Keep all shingle bottoms a minimum of 1/2 inch above the lower leg of any flashings to minimize the wicking of water, which can lead to staining and possible decay.

Wood Wall Shingle Installation Details for Building Corners

Our wood shingle photos below show two methods of fitting inside wall corners.

As extra protection, it is a good idea to add a layer of flashing or No. 30 felt paper at inside and outside corners. If felt is used, crease it at corners for a tighter fit. A simple, attractive inside corner can be achieved by butting the shingles to a 5/4-inch square cedar strip nailed into the corner (Photo, right).

Below our photographs show two wood shingle details for constructing outside wall corners, also demonstrated in the sketch above.

For fast and simple outside corners, butt the shingles to corner boards made from 1x or 5/4 stock (see Figure 1-17 above and our photo, below-left).

Another more labor-intensive approach is to “weave” inside and outside corners by alternating two shingles on one side with two on the other (photo, above right). On an outside corner shingled this way, the exposed edge alternates every course. To keep outside corners tight, nail through the butts with a small hot-dipped galvanized finish nail. On woven inside corners, alternating courses keep the joints tight.

Panelized Wood Wall Shingle Installation

To simplify and speed up installation, several manufacturers offer sidewall shingles attached to panels with either staples or adhesive (see Figure 1-18). The wood shingle panels range from one-course panels 32 inches wide to three-, four-, and five-course panels 2 feet wide by 8 feet long, including panels with decorative patterns. Some wood siding shingle manufacturers also offer prefabricated inside and outside corners, radiused panels for curved walls, column wraps, and other types of labor-intensive details.

Guide to Finishing Wood Shingle Exterior Walls

Eastern white cedar shingles are often left unfinished and tend to weather to an attractive silver gray—particularly with exposure to sun and salt air in coastal climates. However, splashback and other uneven weathering conditions can lead to dark streaks or splotches (photo, below left, Hudson Valley, NY).

To accelerate the weathering process and to guarantee uniformity of color, a bleaching oil is recommended. For a pigmented finish, use an oil-based, semitransparent stain. Prefinished white cedar shingles are available with a stained finish or pretreated with bleaching oil.

If left unfinished, red cedar shingles will tend to weather to a dark reddish-brown color. (See our photo above right, Two Harbors MN) To guarantee uniformity of color, red cedar shingles should be finished with an oil-based clear finish, oil-based stain, or bleaching oil.

If a painted finish is desired, use an oil-based primer with a 100% acrylic top coat for best results. Factory finished shingles and shakes are available pre primed or pre stained, ready for a top coat after installation. See more under “Exterior Wood Finishes” (page 42 in Best Practices Guide).

-- Adapted with permission from Best Practices Guide to Residential Construction.

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Technical Reviewers & References

• InspectAPedia.com^® - Daniel Friedman - Publisher & Editor.
• Steven Bliss served as editorial director and co-publisher of The Journal of Light Construction for 16 years and previously as building technology editor for Progressive Builder and Solar Age magazines. He worked in the building trades as a carpenter and design/build contractor for more than ten years and holds a masters degree from the Harvard Graduate School of Education. Excerpts from his recent book, Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com.
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BEST PRACTICES GUIDE to Residential Construction
EXTERIOR WALL SIDING TRIM & FINISHES
  >ADHESIVES, EXTERIOR CONSTRUCTION
  CAULKS & SEALANTS, EXTERIOR
  FIBER CEMENT SIDING
  FLASHING MEMBRANES PEEL & STICK
  FLASHING for METAL ROOFS
  FLASHING ROOF-WALL SNAFU
  FLASHING WALL DETAILS
  GALVANIC SCALE & METAL CORROSION
  GLUES ADHESIVES, EXTERIOR CONSTRUCTION
  HOUSEWRAP AIR & VAPOR BARRIERS
  HOUSE PARTS, DEFINITIONS
  HOUSEWRAP INSTALLATION DETAILS
  HOUSEWRAP PRODUCT CHOICES
  HOUSEWRAP at SILLS, SOLES, TOP PLATES
  WOOD SHINGLE INSTALLATION
  WOOD SIDING PRODUCT CHOICES
  WOOD SIDING INSTALLATION
  WOOD SIDING FLASHING DETAILS
  WATER BARRIERS, EXTERIOR

• Best Practices Guide to Residential Construction, by Steven Bliss. John Wiley & Sons, 2006. ISBN-10: 0471648361, ISBN-13: 978-0471648369, Hardcover: 320 pages, available from Amazon.com and also Wiley.com. See our book review of this publication.
• Paul Galow - technical consultant on networking, LAN design, applications support. Galow Consulting Services, 914-204-1749, email: paulgalow@galowconsulting.com
• John Rudy, Advantage Home Inspections, Flemington N.J. 08822 home inspector, 908-806- 6364, Home, Radon & Termite Inspections, Central & Parts of North New Jersey, email: jonadvantage1@yahoo.com

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

• Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
• Best Practices Guide to Residential Construction, by Steven Bliss. John Wiley & Sons, 2006. ISBN-10: 0471648361, ISBN-13: 978-0471648369, Hardcover: 320 pages, available from Amazon.com and also Wiley.com. See our book review of this publication.
• Decks and Porches, the JLC Guide to, Best Practices for Outdoor Spaces, Steve Bliss (Editor), The Journal of Light Construction, Williston VT, 2010 ISBN 10: 1-928580-42-4, ISBN 13: 978-1-928580-42-3, available from Amazon.com
• The Journal of Light Construction has generously given reprint permission to InspectAPedia.com for this article. All rights and contents are ©Journal of Light Construction and may not be reproduced in any form.
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