Wood Panels and Humidity

Coping with wood movement

All wood workers need to be aware of wood movement when building furniture projects. Failure to consider this important factor can cause wood panels to crack or split.

My high school biology teacher compared the structure of a piece of wood with a bundle of straws. The straws represent the cells and capillaries of the wood. When a tree is growing water and food are transferred up through the cells and are carried throughout the tree.

Once a tree is fell the free water in the wood is lost rather quickly but the bound water trapped in the straw like cell is slower to dissipate. As the level of bound water is reduced these straw like cells get narrower in diameter but maintain their length. This is the fundamental reason that wood expands and contracts across its width but has almost no expansion length wise.

When working with wood it is very important to allow the wood to expand and contract with changes in humidity. As humidity rises the straw like cells expand in diameter with the opposite effect occurring as the relative humidity falls.

Ways to accommodate expansion

Lets use a cutting board for the first example. A solid wood cutting board with a bread board edge secured with a tongue and groove joint. One edge has the bread board edge secured on both ends with a dowel through the tongue The other bread board edge is secured with the same tongue and groove joint but this end only has a dowel in the center of the piece.

The end secured with two dowels will develop a crack in the main panel. Since the length of the edge piece doesn't change having it fixed across the width of the main panel from expanding.

Alternatively, the opposite end of the cutting board is only fixed in the center. The main panel is free to expand and contract towards the ends. The only visual difference would be that the ends of the edge piece are no longer flush with the edge of the main panel.

The second example uses a large glued up panel such as a table top. If the table top was fixed to the rails across the width of the panel the rise and fall of humidity would undoudtable cause the panel to split.

The best method to overcome this is use wooden clip to attach the two pieces. A 1/4" x 1/4" dado milled on the inside upper edge of the rails. This accepts a wooden clip that fits into the dado and is then secures to the underside of the table top. This will security hold the top hold the top onto the rails without restricting the expansion and contraction of the large panel. Without this the table top would slowly start to open up.

In general anytime you are fixing one piece of stock across a large glued up panel measures need to be taken to allow the panel to move. Remember that it will expand across its width but not its length. Using one of the two methods mentioned above you will be able to prevent your glued up panels from splitting.

About The Author

Dave Markel is the author of "The All Wood Working Journal". He has helped hundreds of individuals improve their wood working skills. Visit his site at http://all-wood-working-plans.com. Subscribe to the All Wood Working Journal at http://all-wood-working-plans.com/wood-working-tips.html.

---

Building a Backyard Play Structure

A child's dream backyard includes a play structure complete with... Read More

Cordless Impact Wrench - Not the Same Tool as Your Cordless Drill

The cordless impact wrench is quickly gaining in popularity among... Read More

Consumer Guides: Finding A Quality Contractor and Power Washing Tips

Power washing is the application of high pressure water spray.... Read More

The Benefits of Radiant Heat, Comparison

What are the Benefits of Radiant Heating and how do... Read More

Art and Design

Maybe you've faced it before ? a new house with... Read More

Warm Up the Night! Patio Heaters and Fire Pits

In some areas right now, the weather is ideal for... Read More

Tearing Down the House

Last year, we bought this big ol' 1887 house. We... Read More

Dual Pane Window Glass Repair

For the past few weeks, I have been explaining how... Read More

Whats Underfoot? A Quick Guide to Patio Surfaces

Patios and terraces have always been popular outdoor spaces. Whether... Read More

Rodent Proofing Your Home

It's that time of year where rats and mice are... Read More

How To Buy A Conservatory In The UK

The first question is, what is a conservatory?There is no... Read More

Wood Panels and Humidity

Coping with wood movementAll wood workers need to be aware... Read More

Getting the Power to Control

One of the advantages of using machines to control processes... Read More

Strapping a Ceiling

Prior to hanging sheetrock to ceiling joists it is important... Read More

Choosing The Right Window

When you have reached the decision to purchase new windows... Read More

Use Ladders Safely

The Consumer Product Safety Commission reports that each year more... Read More

Feng Shui Tips For Your Home Office

Did you know that over 50% of women now run... Read More

How I Got A Robot To Vacuum The House

Like most people I really hated to vacuum the house.... Read More

Lighting up Your Life

You are visiting a friend that has just had a... Read More

Buying The Right Bed Sheets For Your Bed

You spend a lot of your life in your bed... Read More

Sofa slipcovers - Give your home an instant makeover!

Sofa slipcovers are designed to be easy to fit over... Read More

Hidden Causes of Water Damage in the Home

In addition to causing destruction, water damage also has an... Read More

Would You Steel Your Household Appliances

Would you steel your appliances? That is a question many... Read More

Laminate Flooring is Built for the Twenty First Century

The tradition of hardwood floors dates back hundreds of years,... Read More

Sump Pump Installation for Do-It-Yourselfers

According to recent surveys, over 85% of all homes with... Read More

Pre-drawn House plans the Benefits and Styles

Pre-drawn house plans are those that are drawn by architects... Read More

How to Layout Recessed Lighting

One of the most important principles to understand when designing... Read More

Change The Style Of Your Interior With A Minimum Of Costs

The style of your interior depends for a great part... Read More

Avoiding Leaks When Installing Vinyl Retrofit Windows

These days a lot of homeowners are replacing their old... Read More

The Best Way To Clean Carpet?

What is the absolute best way to clean carpet? Carpet... Read More

Help Choosing Door and Window Hardware

Who would be the best person to help you find... Read More

Painting and Decorating Tile

Ceramic tile can be beautiful and elegant. But it can... Read More

How Stained Glass Can Add Elegance To Your Home

If there is one way to throw a new light... Read More