Wood warps in furniture as it expands and shrinks in uneven intervals from moisture, or from uneven pressure being applied over time. The warping is a result of the wood’s grain patterns, sunlight and UV rays evaporating it unevenly, pressure on a section like the middle, and anything else that causes it to shift unevenly.
Warping is where the wood board itself distorts which could be bending inwards, twisting, and becoming misshapen, and the most common cause of warping is from moisture.
Moisture can warp the bottom of a piece of furniture like a cabinet or bookshelf if it's exposed to frequent spills, splashes from mopping the floor, leaks, dog bowls splashing, etc... These exposures allow the bottom section of the wood to absorb moisture while the top remains dry, causing the wood to expand and contract unevenly causing it to warp.
Tables that are left in partial sunlight may warp as the sunbeams dry out the exposed section of the wood table faster and more frequently than the sections that get indirect light. In some types of furniture like a rocking or adirondack chair with wooden boards, you may see cupping or bowing which are two of the three main types of warping.
- Cupping is where the sides of the wood are higher than the center making the board appear like a cup.
- Bowing is more common in floor boards and is when the ends on the two lengths rise up making the board resemble a bow like a bow and arrow.
Tall pieces of furniture like an armoire, the cabinet on a murphy bed, and bookshelves (both the sides and the shelves) can warp because of the pressure from the weight of the furniture itself, or the items stored within and on them. This is why it is important to check the quality of the wood and the structure of the design if you want the piece to last.
All wood is susceptible to warping, not just furniture, but some types of wood are more likely to warp more quickly if the wood is not treated and furniture is not cared for to prolong its life.
Which Furniture Wood Warps Fastest
Softwoods like Pine, Spruce, and Fir tend to absorb more moisture than hardwoods like Mahogany, Teak, and White Oak due to them being less dense than hardwoods. The lack of density allows for quick moisture absorption.
If untreated or the sealant becomes compromised, more moisture can get into the softwood causing it to expand. More expansions and contractions stress the structure of the wood more frequently increasing its likelihood to warp.
Fun fact: Hardwoods have pores and softwoods do not, which is why we refer to density instead of saying porous when it comes to moisture absorption for warping.
The grain patterns of the wood and pieces of lumber impact warping with straight grains being the least susceptible as they are more likely to expand and contract evenly than wood boards with sideways grains, knots, and non-uniform patterns. Hard Maple, Ash, and some types of Pine tree like Western White and Ponderosa, can have straight grain patterns and be used in furniture like murphy beds, dining table sets, and couch frames. Cherry, Walnut, and Ash may grow in more twisty patterns causing the grains to not be as linear and these woods may be more likely to warp if the grain is the cause.
So what about manufactured and engineered woods vs. natural wood furniture?
Engineered wood is less likely to warp than natural wood because the layers of wood boards crisscross the grain patterns throughout and help to keep the structure of the board stable. So if the furniture you’re buying will be in an area with high humidity like the coast, go with engineered wood over natural wood as it will prolong life, and it can still look great.
How to Prevent Wood Furniture from Warping
All wood warps over time, but you can be proactive to extend the life of your pieces with proper care and maintenance. Here’s some of the ways to help prevent wood furniture from warping.
- Keep your home climate controlled including using humidifiers and dehumidifiers for moisture control.
- Prevent wood furniture from getting direct sunlight so you can keep moisture release in even intervals.
- Do not place heavier items in or on wood furniture than it can handle. Check to make sure the items do not bend the boards, and if they do remove them.
- If you see a board warping, either replace it or add a support beam to it to help keep it from warping further.
- Apply a high grade finish and moisture resistant sealant if you notice it wearing off, this is normally recommended every 1 - 3 years depending on the manufacturer of the sealant.
Warping is part of what wood furniture does, but you can slow its progression with furniture by using engineered wood, keeping the room it is stored in with even humidity levels, ensure the wood furniture is not in direct sunlight, and have regular furniture care routines.
