While fixing non-conformities in architectural woodwork during fabrication or installation adds time and money to a project, it’s possible to bring the products up to the expected standard. But warping and excessive dimension change caused by poor storage and care of materials can ruin products no matter how skillfully they’re assembled. That means meeting the proper architectural standard of care for materials is arguably the most important factor in achieving a successful project outcome.
AWI encourages all architects to include the AWI-200 – Care and Storage standard in their woodwork specifications to avoid unsuitable humidity conditions and other issues. But to ensure you can deliver superior products every time, here are a few tips on how to care for and store materials for an architectural woodworking project.
Storing wood materials
Since storage requirements before installation are the same for wood products of any aesthetic grade, it’s generally quite easy to maintain good habits. Simply store your products on a flat, clean surface that’s elevated off the floor, and protect them from direct sunlight, excessive temperatures, moisture, and changes in relative humidity. Before handling stored products, clean your hands or put on gloves to avoid marking or damaging the wood.
Controlling temperature and humidity conditions
Even when wood has been kiln dried to an appropriate moisture content, some dimensional change will still occur with normal fluctuations in humidity. But if wood is stored or installed under inappropriate temperature and humidity conditions, it will shrink or swell far beyond acceptable levels. This can result in warping or splitting, and possibly joint failure.
Changes in temperature alone won’t actually affect the size of the wood if relative humidity remains constant. But higher temperatures generally result in lower relative humidity, which leads to a lower moisture content and therefore shrinkage. Lower temperatures lead to higher relative humidity, causing higher moisture content and thus swelling. And since a 1% change in moisture content can cause a 0.5-1% change in the size of the wood, maintaining relative humidity is vitally important.
However, what constitutes optimum product moisture content depends on where you’re working within the continental United States. To help you determine appropriate levels of wood humidity, we’ve prepared the following table and Climate Zone Map:
For proper storage and care of wood materials, maintain the necessary relative humidity between these recommended tolerances. Your materials should be kept in a clean, closed building or area in which HVAC has been installed. Products should be acclimated to the installation environment for at least 72 hours before they’re installed to allow the wood to reach a moisture content equilibrium.
For climate-controlled applications:
- Deliver products in an area that has been broom cleaned, and in which wet work is dry and overhead work is complete.
- Maintain the temperature between 15.5-32° C (60-90° F).
- Don’t allow relative humidity to fall outside of the optimum range for at least 24 hours for any reason.
For non-climate controlled interior or exterior applications:
- Deliver products in an area that’s clean and protected from moisture and direct sunlight.
- Prepare a schedule for ongoing monitoring and maintenance, including any necessary refinishing and touch-ups.
- Protect the products from direct sunlight, excessive moisture, and standing water.
Maintaining and protecting wood materials
Impact damage
Excessively or repeatedly impacting wood cells will lead to compacted dents in the material’s surface. When operating near wood products, take care to avoid accidental collisions.
Direct heat
Concentrated high heat will irreversibly mark wood surfaces. Avoid placing hot plates, pans, and other objects close to or in direct contact with finished surfaces. If this is necessary, first place a heat-proof surface onto the wood.
Dust
Dust can be abrasive, which will cause the wood finish to dull over time. Regularly clean wood materials to avoid the accumulation of airborne dust.
Liquids
Sustained exposure to liquids or high moisture can permanently stain or oxidize wood. If liquids are spilled on wood materials, immediately wipe them dry.
Direct sunlight
Photo degradation occurs when wood is exposed to direct sunlight for an extended period. This gradually changes the color of the wood whether or not it has been finished. These changes are generally irreversible.
Improper use
Doors, drawers, hardware, and other wood products are built with a specific purpose. Improper use of the product for other purposes can degrade their functionality over time.
Cleaning wood products
Keeping wood products in excellent condition requires a regular cleaning routine. For light cleaning, lightly dampen a soft, lint-free cloth with water or an inert household dust attractant and gently wipe all surfaces. If dirt, oil, or grease deposits have accumulated, dilute a mild flax soap following the manufacturer’s directions and apply this to the necessary surfaces using a soft, lint-free cloth.
Never use cleaning products that contain ammonia, wax, grit, or silicone. These can damage the wood finish over time, and may interfere with the quality of refinishing and touch-ups.
AWI-200 – Care and Storage
This nationally recognized architectural standard of care details proper conditions for protecting woodwork and related interior finishes. It covers temperature, humidity, handling, and other factors before, during, and after installation. Following AWI-200 ensures you maintain precise control over the final quality, performance, and longevity of your project.
When project specifications include AWI-200, responsibilities for the dimensional change of wood products are as follows:
- Due to improper design: the design professional
- Due to improper relative humidity exposure during on-site storage and installation: the general contractor
- Due to humidity extremes after occupancy: the owner
If you’re an AWI Member, you’re also entitled to a wide range of educational content for materials, submittals, and casework. This includes plans, articles, videos, seminars, and more. Visit our Education section to continue building your knowledge and skills, or become an AWI Member to access leading educational resources.