Wood Plank Sheathing
cladding: MATERIALS ENCYcLOPEDIA
Applications for this system
Rainscreen cladding (vertical or horizontal orientation)
Structural sheathing (horizontal orientation, specific nailing pattern required)
Aesthetic sheathing (vertical or horizontal orientation)
Surface finish treatment
Ratings Chart for wood plank sheathing and cladding
The ratings chart shows comparative performance in each criteria category. Click on the tabs below for detailed analysis of each criteria.
- HOW THE SYSTEM WORKS
- ENVIRONMENTAL IMPACTS
- EMBODIED CARBON
- ENERGY EFFICIENCY
- MATERIAL COSTS
- LABOUR INPUT
- SKILL LEVEL REQUIRED
- SOURCING & AVAILABILITY
- CODE COMPLIANCE
- INDOOR AIR QUALITY
- FUTURE DEVELOPMENT
Wood plank sheathing System
Wood (usually softwood) is milled to a desired size and profile. There is a wide variety of typical wood siding profiles. Wood may be fastened vertically to a series of regularly spaced wooden straps run horizontally, or fastened horizontally to straps run vertically.
Profiles and layouts are designed to overlap or fit together at seams between planks to minimize the possibility of water penetration. Fasteners may be hidden or left exposed depending on profile and aesthetic preference.
Environmental Impact Rating
Harvesting — Negligible to High
A wide variety of forestry practices are used to harvest wood cladding. At best, impacts are kept to a minimum, but at worst can include habitat destruction, resource depletion, soil erosion and silting and contamination of waterways. Third-party certification can help to ensure that impacts are minimized.
Manufacturing — Negligible to Low
Most wood cladding is milled to maximize the potential of each log. There can be as few as one step (rough sawing) and as many as four steps (rough sawing, planing and several steps to mill a profile) to the process, depending on the type of profile and finish being applied.
Transportation — Negligible to High
Sample building uses 1,395 kg of wood siding:
2.1 MJ per km by 15 ton truck
1.3 MJ per km by 35 ton truck
As a heavy material, wood will have significant transportation impacts if it travels long distances.
Installation — Negligible
Waste: moderate to high
Compostable — Untreated wood scrap. Quantity may be low or high depending on the application.
Recyclable — Metal fasteners. Quantity will be low.
Landfill — Pre-finished wood scrap.
Chart of Embodied energy & carbon
Wood sheathing or cladding will not have a large impact on energy efficiency. When used as structural sheathing, the gaps between planks will require the use of a sheet-style air control layer to properly prevent air migration into the wall.
Material costs: Low to high
There are many types of wood siding and sheathing, from low-cost, rough-cut overlapping options to planed, tongue-and-groove options. Species can vary regionally, which also affects costs. Wood siding is one of the most wide-ranging options in terms of material costs.
Labour Input: moderate to High
The type, quantity and direction of strapping will have a large impact on labor input. Most styles of wood cladding have similar labor inputs for installation. If the wood cladding is being finished on-site, this will add significant time prior to the installation process.
Avoid breathing sawdust during cutting.
Skill level required for homeowners
Preparation of substrate — Easy to Moderate
A homeowner with basic carpentry tools and experience can apply a single or double layer of strapping.
Installation of sheathing — Easy to Moderate
A homeowner with basic carpentry tools and experience can apply a wood sheathing/cladding. A good installation requires an understanding of how the cladding is managed at corners and intersections. Trim work for some wood claddings can be moderately difficult.
Finishing of sheathing — Easy
Pre-finished siding requires all cut ends to be painted with the same finish. If wood cladding is unfinished, applying treatment is straightforward but can be time-consuming. Raw wood cladding requires no additional finishing time.
Sourcing & availability: Easy
Wood cladding is widely available in many styles from building supply outlets and specialty siding shops.
Raw wood lasts a long time as a cladding if installed properly. It can take seventy-five to a hundred years for raw wood to deteriorate to the point where it is no longer useful, with UV radiation being the most potent agent of decay.
Durability issues are more likely to be caused by finishes and the difficulties involved in refinishing. Paint, especially when applied only to the exterior face of the wood, will often crack and peel, requiring labor-intensive scraping and sanding to refinish. Stains, mineral treatments and washes will fade over time but will not be prone to the same cracking and peeling as paint. Deteriorating finishes will often cause a homeowner to remove and replace wood siding that feasibly had many more years of service life, so choosing a good finish and applying it to all six sides will go a long way toward extending the serviceable lifespan of wood cladding.
Wood cladding can also cup and warp, becoming visually unappealing. This is often due to improper fastening and/or finishing of the wood, and can be avoided by proper installation.
Wood cladding is an acceptable solution in all codes. Regions with termites may have restrictions or regulations to avoid infestation.
Indoor air quality: n/a
Resources for further research
Ireton, Kevin. Exterior Siding, Trim, and Finishes. Newtown, CT: Taunton, 2004. Print.
DeKorne, Clayton. The Essential Guide to Exteriors. Washington, D.C.: Hanley Wood, 2005. Print.
Brumbaugh, James E., and John Leeke. Complete Siding Handbook: Installation, Maintenance, Repair. New York: Macmillan, 1992. Print.
The growth of third-party certification programs is increasing the availability of sustainably harvested wood products, including cladding. Nontoxic finishes are also becoming more widely available.
Tips for successful wood plank sheathing
1. Wood cladding will have the longest lifespan if installed as a ventilated rainscreen. Be sure plans include a vertical air channel behind the siding, with a screened air inlet/outlet at the bottom and top of the wall. For vertical siding, this may require strapping vertically first, then horizontally.
2. If wood cladding is getting a surface treatment, be sure to apply this to all six sides of every piece. Wood that is only treated on the exterior face is prone to cupping and twisting, as well as moisture damage from the backside.
3. Be sure to use fasteners of an appropriate size with the proper kind of head for the particular profile of wood. Fasteners should be galvanized, stainless or made of a non-corroding metal.
4. Design to keep wood cladding at least 30 cm (12 inches) above finished grade, and ensure that wood will not be in the path of constant splashback from the roof.
5. There are many excellent resources available for the installation of every type of wood siding. Be sure to research all applicable strategies and techniques.