Buildings with Quality Assurance

For long-term durability, conformance to the requirements of the government building code is essential at every stage of the building process. Inspection is required for all construction materials covered by the building codes and is typically performed by the local code agency. Special inspection by third-party agencies for construction practices critical to the building's structural capability, such as tight diaphragm nailing in high seismic areas, are enumerated in Chapter 17 of the IBC, Structural Tests and Special Inspections. Treated wood products should confirm to AWPA standards, and should carry the quality mark of an accredited inspection agency of the American Lumber Standard Committee (ALSC) or ICC Evaluation Service.

This photo shows how a multi-story wood building can be protected from the elements. Photo courtesy of Togawa Smith Martin, Inc.

Buildings that are Properly Maintained

Also essential to building longevity is regular maintenance, repair and renewal. Five years after installation (or sooner), wood exposed on the exterior should be inspected, and then every two years thereafter. Sunken paint and surface collapse both indicate subsurface wood decay, which requires repair. To minimize moisture problems, cladding should be inspected annually for signs of wear and for green algae stains; through-wall flashing should be examined for brown stains. Exposed wood should be properly painted, stained or otherwise protected. Re-treat with termiticides at appropriate intervals. Heavy shrubbery should be kept from exterior walls, and sprinklers pointed away from wood walls. Roof gutters should be kept unclogged. Any plumbing leaks should be promptly repaired.

Photo courtesy of Stephanie Tracey

Wood: A Material of Choice

Because of its cost effectiveness, ease and efficiency of construction, versatility, and sustainability, wood will continue to be the material of choice for many structural applications. Protecting the longevity of wood buildings starts with good design and construction practices—both areas in which architects can influence the optimum use of wood. When appropriate steps are taken, architects can tap the virtually unlimited design possibilities of wood material, while delivering buildings that will perform well for owners, occupants, and the environment—and for centuries.

Information Sources

Design of Wood-Frame Structures for Permanence, American Wood Council

Managing Moisture and Wood, Canadian Wood Council

Moisture and Wood-Frame Buildings, Canadian Wood Council

Guide for Designing Energy-Efficient Building Enclosures for Wood-Frame Multi-Unit Residential Buildings in Marine to Cold Climate Zones in North America, Finch, G., J. Wang, and D. Ricketts, 2013, www.fpinnovations.ca

USDA Forest Products Laboratory

durable-wood.com, Canadian Wood Council and FPInnovations

Building Science Corporation, www.buildingscience.com and buildingsciencepress.com

ENDNOTES
1	www.designbuildsource.com.au/melbourne-launches-the-worlds-tallest-timber-building
2	O'Connor, J., Horst J.S., Argeles, C, 2005. Survey on Actual Service Lives for North American Buildings, FPInnovations, Proceedings, 10th International Conference on Durability of Building Materials and Components
3	Wang, J., Morris, P.I. 2011. Decay initiation in plywood, OSB and solid wood under marginal moisture conditions. The International Research Group on Wood Protection Document No. IRG/WP 11-20469
4	Canadian Wood Council,http://www.cwc.ca/index.php/en/design-with-wood/ durability/durability-hazards/about-moisture-and-wood
5	Moisture and Wood-Frame Buildings
6	Hazleden, D.G., Morris, P.I. 1999. Designing for durable wood construction: the 4 Ds. Durability of Building Materials and Components
7	USDA Forest Products Laboratory
8	Morris, P.I. 2000. Integrated control of subterranean termites: the 6S approach. Proceedings American Wood Preservers' Association Annual Meeting. (96): 93-106.
9	North Carolina Department of Agriculture and Consumer Services
10	American Wood Protection Association

	The reThink Wood initiative is a coalition of interests representing North America's wood products industry and related stakeholders. The coalition shares a passion for wood and the forests it comes from. Innovative new technologies and building systems have enabled longer wood spans, taller walls, and higher buildings, and continue to expand the possibilities for wood use in construction. www.rethinkwood.com
	American Wood Council is the leading developer of engineering data, technology, and standards on structural wood products in the U.S. These tools are used widely by design professionals, building officials, and manufacturers of traditional and engineered wood products to ensure the safe and efficient design and use of wood structural components. www.awc.org
	WoodWorks is an initiative of the Wood Products Council established to provide free one-on-one project support, education, and resources related to the design of non-residential and multifamily wood buildings. If you have a project that requires technical expertise in wood design, contact help@woodworks.org. www.woodworks.org