Climatic change & its effect on wooden furniture

Climatic change and its effect on wooden furniture

By Ken Gallacher, Specialized Repair Company - American Moving & Storage Association - While seated on the witness stand in court, a judge once asked me, "How can you tell if damage to furniture is transit related or not?" Even though the judge was satisfied with my lengthy reply, have never found a simple, pre-packaged answer to that question when challenged by a shipper who disagreed with my findings; especially when it involves damage caused by climatic effects. Most of the time, I can't get past the first sentence of my explanation.

How does one explain years of experience and exposure to a disbeliever?

Comebacks like "I'm just good-that's all" usually do nothing more than intensify a shipper's frustration following the denial of their claim.

Having worked with wood and claims for years, I can easily tell when wood has split from warpage as opposed to stress breakage. I have also witnessed that warpage can take place in as little as three hours on some woods. Convincing a shipper that a carrier is not responsible for this is the greatest challenge I face on denials.

A shipper's most common rebuttal to a climatic effects denial is, "Well, it wasn't that way before they moved it." On this point I almost always agree, but further explain that warpage that occurs during the move is not the carrier's fault. It cannot be prevented even with climate controlled warehouses, because the relative humidity may be different from one place to another.

Wood acts as a hygrometer for the area that it is in. Any article made of wood is liable to more or less warping due to changes in humidity. Wood is a hygroscopic material which means it tends to give off its moisture to a dry atmosphere or it takes on moisture from a damp atmosphere until an equilibrium between the two is established. Approximately one percent dimensional change takes place with each three percent change in the moisture content of the wood. The best analogy would be that of a sponge; when it dries, it shrinks, when it absorbs moisture, it swells.

From my own observations, wood furniture items that are moved from humid regions to arid locations seem to have the most drastic effects. A rosewood cabinet moved from the Orient or coastal states to a dry state like Utah or Nevada will sometimes incur three quarter inch splits in the face panels due to the moisture expelled from the wood. Unfortunately, there is no feasible way to predict which piece will or will not crack.

Many interstate carriers have had to unnecessarily bear the burden from claims like these. Some restorationists, perhaps inexperienced, have not recognized climate caused damage, and conducted repairs under the assumption that the shipper's claim for transit caused damage was legitimate.

Other types of damage are loose spindles, mostly on chairs. Perpendicular grain joints fall prey to climatic effects more than most people realize. Very seldom have encountered claims where this was not the case. Quite often one can tug slightly on a loose spindle and feel a side to side movement in the hole. This is usually solid proof that the wood spindle shrank., causing the glue joint to fail.

Veneers also stiffer from climatic change. These thin layers of wood also expand and contract. When finishes fully cure and dry, they become brittle and lose their elasticity as the veneer expands. As a result, the finish buckles along the grains when the veneer shrinks. This is known as checking, a peeling and lifting effect of the finish, along the grains of the wood.

Another common claim I encounter related to climatic damages are oak tables with center pedestals. Since these pedestals are assembled with several mitered pieces of oak, the risk of shrinkage is high. Shippers have often assumed that the reason their table ended up in pieces was because the mover put something heavy on it. The proof to the contrary is that when we try to reassemble the pedestal, the pieces no longer match up to each other because the, shrank or twisted.

So how do we defend this point? I did some homework and found some second opinions. According to an article written by Bruce Hoadley, a wood science professor at the University of Massachusetts, moisture variation is to blame when perpendicular wood joints fail when moved to different climates. He also states that as a result of moisture cycling, the dimension of 'wood perpendicular to its grain direction can change by up to four percent of its original dimension. This amounts to a change of 1/32 of an inch across a one inch diameter tenon.

And from the Detroit Drop Hammer Board Company: No matter how thoroughly lumber is seasoned, preshrunk, or finished, some shrinking and swelling in service is inevitable because wood is seldom used under constant changing. Wood in service generally reaches an average moisture content, and changes in relative humidity cause fluctuations about this aerage.

The majority of people who sustain climatic damage on their move are shocked to find out that wood moves. I might also add that the climatic damage inspect can and does appear as mover caused damage. Huge splits and curled table tops are no doubt an emotional blow to someone who may have had the piece for years. Antiques that have been in the family for generations can be unfortunate victims of Mother Nature's work.

Because emotions usually run high with these related damages, I normally refrain from announcing my intent to deny the claim until I make every effort to educate the shipper as to the nature of the problem and how it occurs. This always helps to defuse their reaction, making it possible to present the carrier's position. Many of my clients have not disputed these reasons for denial, once they had a full understanding of the situation.

Denials for these types of claims fall under the 'inherent vice' definition-damage that would have occurred no matter who moved it. Nevertheless, there will always be the person who incredulously asserts that the movers mishandled their furniture, regardless of how credible the explanations are to the contrary. Qualified restorationists who can readily recognize climate caused damage will be a carrier's best defense on these types of claims.

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