VIDEO Avoiding Wood Damage from High Heat

High temperatures and low humidity cause woodwork to move around. Correct design for this sort of movement can eliminate the problem. Architectural Woodworking Institute’s Randy Estabrook discusses the rising role of heat in defective woodwork.

Temperature alone doesn’t affect wood greatly, but relative humidity does. All wood products contain some moisture and exchange this moisture with water vapor in the atmosphere according to the relative humidity. If humidity is high, wood absorbs more moisture and swells. If it’s low, wood releases moisture and shrinks.

According to the Woodworking Network, a 1 percent change in moisture content can result in a 0.5 percent to 1 percent change in the size of the wood. This moisture content change occurs when relative humidity changes by just 5 percent. Therefore, dimensional problems such as movement, shrinkage, expansion, and warpage are the most common effects of humidity on architectural woodwork.

These problems can be the result of faulty design and unsuitable or uncontrolled amounts of humidity during storage, installation, or use. Indeed, if controls aren’t in place for sustaining a constant, suitable relative humidity in a building, the woodwork could possible fail.

Estabrook says there are various ways to ensure that architectural woodwork, once installed, isn’t negatively impacted by heat and humidity. Correct design, construction, and installation will all contribute to the overall quality of the woodwork, but humidity control is the important aspect of preventing dimensional problems.

Maintain Relative Humidity—Relative humidity must be consistently controlled; extremes in humidity or sudden, repetitive changes are likely to cause issues with the woodwork.
Avoid Localized Heat—Try not to expose the woodwork to high, localized heat sources such as hot plates. Even direct sunlight will change the look of your woodwork over time.
Maintain the Woodwork’s Finish—Don’t use abrasives, chemical or ammonia cleaners to clean architectural woodwork. Instead, use a damp, lint-free cloth to dust the surfaces, and a mild flax soap to remove oil or grease.
Avoid Direct Contact with Moisture—When correctly finished, architectural woodwork is fairly moisture-resistant. However, if moisture accumulates on any wood product, it will eventually cause damage. Make sure to wipe surfaces clear of accumulated moisture. This will also prevent stains on the wood as a result of oxidation.

Information and guidance about the care and storage of architectural woodwork can be found in the AWI-200, a chapter in the Architectural Woodwork Standards handbook that covers the important features of installation, storage, site conditions, and relative humidity requirements.

The 13 AWS Finishing Systems
The 13 AWS wood finishing systems are detailed on page 115 of section 5 of the Architectural Woodwork Standards. Here, you will find more information about the types of wood finishing systems, their characteristics, and the benefits and drawbacks of each one.

• Lacquer nitrocellulose
• Lacquer, pre catalyzed
• Lacquer, post catalyzed
• Latex acrylic, water-based
• Varnish, conversion
• Oil, synthetic and penetrating
• Vinyl, catalyzed
• Acrylic cross, linking, water-based
• UV curable, acrylated epoxy, polyester or urethane
• UV curable, water-based
• Polyurethane, catalyzed
• Polyurethane, water-based
• Polyester, catalyzed

Section 5 contains more information about architectural woodworking finishes, including their purpose, a more detailed explanation of the considerations to remember, techniques to consider, compliance requirements, and more.

AWI is currently developing AWI/ANSI standards for Factory Finishing. “During the ANSI canvass and public comment process, substantive changes were made to ensure harmonization with existing ANSI standards,” says AWI. Public comment on this aspect of the standards is open Jan. 28, 2022 through Feb. 27, 2022. Interested parties who wish to comment may use this link or contact either CDermyre@awinet.org or hunter@awinet.org for details about the process.

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