Hello fellow makers,

I've experienced some cupping on my solid American Oak tables in QLD and NSW recently, and I know they have been experiencing some unprecedented fluctuations in both humidity and temperature as of late.

If anyone has experience in this area, or knows some great resources
regarding standards for ideal relative humidity and temperature for furniture maintenance in the home, any recommendations would be greatly appreciated.

Regards,

QLD and NSW? Cupping is either caused by not allowing seasonal wood movement, or moisture changes in the wood. Are you checking the moisture content of the wood when you buy it? Do you finish the bottom surface of the table like the top? How wide of boards are you using? Are you fastening a breadboard end rigidity to the table top? Lots more data needed!

Queensland and New South Wales are my guess for the abbreviations. That is the other side of where you are Rich.
The US indicates that 35% RH is ideal for kiln dried woods in the 7 - 9% range. The Europeans favor it a bit more humid at %40.
Rich's questions are all valid.
Bruce Hoadley's book "Understanding Wood" is a good place to get answers.

Ideally work will be built with wood that is in equilibrium with the shop environment and its conditions in use. That will depend to some degree on local conditions. If the lumber's moisture content is more than a few points away from use conditions problems may ensue. When the wood is acclimated to the shop and construction and finish details allow expansion/contraction within projected norms issues will be minimized. As David S. said, Hoadley's book is a great place to start.

Cupping in solid oak tables can indeed be a result of fluctuations in humidity and temperature. Wood is sensitive to changes in its environment, and when the moisture content of the wood changes, it can lead to issues like cupping, warping, and cracking. Here are some recommendations and resources to help you address and prevent such issues:

1. **Maintain Stable Environment:**

- Keep the indoor humidity levels as stable as possible. Fluctuations can cause wood to expand and contract, leading to issues.

- Use air conditioning or a dehumidifier to control humidity during humid periods.

- Avoid placing your furniture near heat sources like radiators or direct sunlight, as they can cause localized drying and warping.

2. **Ideal Humidity Range:**

- The general consensus for indoor humidity to prevent wood issues is around 40-50% relative humidity.

- You can use a hygrometer to monitor humidity levels in your home and make adjustments as needed.

3. **Temperature Considerations:**

- While temperature fluctuations can contribute to humidity changes, keeping the temperature relatively stable is also important for preventing wood issues.

4. **Furniture Placement:**

- Avoid placing your furniture in areas with extreme temperature variations, such as near doors or windows that are frequently opened.

5. **Wood Care:**

- Use a quality wood conditioner or furniture polish to maintain the wood's moisture content and protect it from drying out.

6. **Resources for Further Reading:**

- The Forest Products Laboratory (FPL) of the USDA Forest Service offers a guide called "Wood Handbook: Wood as an Engineering Material," which provides comprehensive information about wood properties, including its response to humidity and temperature changes.

- The National Wood Flooring Association (NWFA) also provides resources on maintaining wood floors, which can be relevant for furniture care as well.

- The American Institute for Conservation of Historic and Artistic Works (AIC) has publications on preventive conservation for wood artifacts, which can offer insights into maintaining wooden furniture.

Remember that wood is a natural material and will always have some degree of response to its environment. It's important to strike a balance between maintaining the aesthetic and structural integrity of your furniture while considering the realities of your specific climate and home conditions. If the cupping is significant and you're concerned about your tables, it might also be a good idea to consult with a local woodworking professional or furniture restorer who is familiar with your region's climate challenges and can offer tailored advice.

Ideal Conditions: For solid wood furniture, including oak, the ideal relative humidity (RH) is around 40-60%, and the spray painting temperature should be maintained between 60-75°F (15-24°C). Use a digital hygrometer to monitor RH.
Humidity Control: Use a dehumidifier in humid conditions and a humidifier in dry conditions to maintain stable RH. This can help prevent wood from expanding or contracting excessively.
Avoid Direct Sunlight: Direct sunlight can cause rapid temperature changes and fading. Use curtains or blinds to protect your furniture from prolonged sun exposure.
Climatic Fluctuations: In regions with extreme climate changes, consider using a humidistat to control humidity levels. Seal doors and windows properly to minimize temperature fluctuations.
Regular Maintenance: Keep your furniture clean and use wood-specific polishes or conditioners. This helps protect the wood and maintain its appearance.
Helpful Resources: The Holapaints and Woodwork Institute the National Wood Flooring Association provide resources and standards related to wood and environmental conditions.
https://holapaints.com/spray-painting-temperature/
Consult a Professional: If you're unsure about the specific needs of your furniture, it's a good idea to consult a professional woodworker or a furniture specialist.