How to treat treated lumber right

ECAUSE treated lumber is strong and durable, dealers sometimes forget that it needs proper handling and storage to prevent yard loss and customer complaints.

Both treated and untreated wood can have dimensional change. Bending, twisting, bowing and cupping result flrom stresses occurring within wood as it dries down to the moisture level of the environment. Freshly cut lumber contains a high degree of moisture which evaporates ' into the air, shrinking the wood in both width and length.

Even though seasoned before the pressure treating process, lumber as it is impregnated with preservative solution again becomes full of moisture. After processing, treated lumber can be kiln dried (KDAT) to 150/o or 190/o moisture content or treated as green lumber. The grade and quality marks are indicators of its final moisture content.

However, like any lumber, treated lumber is vulnerable to surface stresses caused by changes in moisture content. Stacks of lumber exposed to rain or excessive sun and wind may develop checks, splits and grain raising.

"Although there is no way known to eliminate warping completely, you can minimize it by balancing the drying of your stock," advises Huck DeVenzio, Hickson Corp. "Don't allow your lumber to dry out and make sure all sides dry evenly."

Proper storage can keep pressure treated stock in prime condition. An open, well ventilated shed with pro- tection from direct sunlight is the best environment for lumber, treated or untreated. Paper wrapped bundles also provide protection against moisture and sunlight.

Dead packs of lumber (banded without stickers) are best kept wrapped or covered out of the sun and wind. If these are allowed to stand unprotected in the yard, the topside will dry out faster than the bottomside, causing problems.

Air is able to circulate around the lumber in shipments separated by stickers. Shielding the top layer firom the sun or turning the top pieces occasionally will even out the drying, DeVenzio advises.

Wood that has been pressure treated with a water repellent as well as a preservative tends to warp less. Because it absorbs and releases moisture at a slower rate than conventional treated wood, the drying proceeds more evenly and warping is less likely to occur.

In humid climates, even lumber under cover can be affected by the growth of mold. While not harmful to the performance of treated wood, the resulting discoloration and odor can make the wood undesirable to customers. The problem can be alleviated by specifying pressure treated wood with a mold inhibitor, an inexpensive additive.

Fire retardant treated plywood and lumber should be stored inside under dry conditions with no exposure to rain, according to Glenn W. Wilson, manager, technical services, Hoover Treated Wood Products, Inc. It is usually shipped with a waterproof cover which should be kept on as protection against rain until it is under cover at the job site. Tarps also can be used to protect fire retardant treated wood from rain.

Story at a Glance

Why proper handling and storage increases plofits, cuts custo mer complaints... how treated wood, FRTW degrades in sun, rain, wind. .. recommendations fior keeping inventory in top shape.

Pressure treated lumber stacked in the yard or racked in the store needs to be kept neat and orderly. Broken bundles scattered by customers handpicking boards should be tidied regularly. Inventories are best turned quickly with first in first out.

Charts explaining quality marks, preservative retention levels and recommended uses are displayed by many dealers in the treated section. Some add signs identifying the manufacturer and guarantees. Consumer Information Sheets also should be posted as part of the industry's Consumer Awareness Program.

Southern Forest Products Association, P.O. Box 52468, New Orleans, La. 70152, has lumber storage literature and a pressure treated wood poster available to help retailers. Posters and CAP literature are available from the American Wood Preservers Institute, 1945 Old Gallows Rd., Suite 550. Vienna. Va. 22182 -editor.