Profiting from western woods requires proper storage

ll--fALLBACKS kill profit margins. \-rBut, with lumber products, chances are that complaints of fungus, stains, twisting or warping should not always be blamed on bad lumber. The lumber was probably fine when it left the mill. The Western Wood affect green lumber, but exposure to sun and warm weather may. The likelihood of stain and decay increases during warm months, necessitating speedy inventory turnover. Green lumber should be kept outside to allow air circulation and perhaps shaded by a roof or cover boards to protect the top course, which is sus-

Products Association reports that many of the "quality" complaints they hear are at least partially due to improper storage, faulty handling or common framing errors.

Lumber is a natural material, changing in response to changes in its surroundings. So, critical to ensuring satisfactory performance are proper air flow and adequate protection to prevent rapid alterations in moisture content and promote gradual acclimation.

As it acclimates, wood gains or loses moisture, swelling or shrinking accordingly. Problems arise when the moisture content changes unevenly or too quickly. Additionally, lumber also is susceptible to fungi and staining.

Story at a Glance

Cut callbacks with proper lumber storage ... how to store a variety of products in the yard and at the job site.

CUp ;:pevialion l[a,lwise,{1om a,slraight :lihe,across'the width of a,piec€:,ol lumi :Der.::: :::: ::::::::,,', iiiiii ii ' ii',',, Oecay,* olsinttgi.iil .ii*.oo iuustance due,to,.action of :wood-dCsiroy; ing:1ungi. Also knowr:as dote; iol br unsouhd wood.

$'ptit - A iengthwise Separalion of a pleoe,bl lumber exlending'trorn one surface through' the piece tO:lhe'optosite surface or to an adjoining:surface.

Twist - A distortion in wood Caused by lhe,,tuming o1,wlndingrst lhe,:ed$et, of, a board so tha! the four comers of any face aie no longer in the same plana ,Wana ;,,Ba!lt;; oi lhe lack::of,troodr:rtrgln any cause except eased edges, on lhe 6dge,oricorndi of ,a pi6ba of lUfiUei:

Warp - Any deviation trom a lrue or plane surface, including bow, crook, cup and,twist or any combination of these.

- Courtesy of Terms of the Trade

Although often such problems are merely aesthetic, sometimes they can lead to degradation of the lumber. The solution is proper storage.

The lumber's moisture content when it leaves the mill determines how it should be handled along the rest of the distribution chain. Unseasoned (green) lumber requires less protection; it can be stored outdoors, uncovered in cool weather for 30 to 45 days without damage.

Stocking green lumber does require quick inventory turns. The first shipment in should be the first shipment out, so green lumber is out of the yard within 30 days. Quick turns also provide some leeway if the contractor lets the shipment sit at the job site for a while.

If the wood is predicted to be stored for longer periods of time, it is safer to buy kiln dried or air dried, though the cost will be higher. If green lumber must be stored longer than a month, WWPA suggests stickering the bundles to permit even air circulation and guard against mold and stain.

Rain probably won't adversely ceptible to seasoning checks if exposed to the sun.

Anti-stain treatments will control molds, mildew and fungi for short periods (usually up to 30 days). Many mills offer these protective treatments - at an additional cost. End painting and, typically more effective, end waxing are other valueadded services from the mill to help reduce end splitting and checking and help retain dimensional stability.

Pile burn, which can lead to structural degradation, may occur when green lumber is permitted to sit closestacked for several weeks in hot. humid conditions. The center of a stack begins to absorb considerable heat, creating ideal conditions for decay-causing fungi. The first sign of pile burn is a white, filmy fungus on the lumber. But often there is little visible evidence that the wood at the center of a stack is decaying until it is broken open.

Again, the best defense is rapid inventory turnover. Stickering the lumber also helps.

Since it is impractical to kiln dry them, posts, beams and timbers are always manufactured green and usually develop seasoning checks while in storage. Although these checks have no effect on the wood's structural performance, excessive checking should be avoided.

To guard against drying too quickly, large dimension lumber should always be solid-stacked and, especially in warm temperatures, stored under a roof. If possible, use wetted burlap or continuous sprinkling to slow the drying and checking process.

Llnlike that of green lumber, dry lumber's moisture content is at or near what it will be once the wood acclimates. As a result, dry lumber is much less susceptible to twisting, warping, cupping and other moisturerelated dimensional stability woes.

Also unlike green lumber, dry lumber must be kept dry. Rain maY undo the value gained by careful seasoning and jeopardize the product's dimensional stability. If storing it outdoors, loosely cover dry lumber with tarps, canvas or paper wrap. WWPA warns against using plastic wraps, which may trap in moisture and heat, accelerating fungal activity.

Dry lumber typically is wraPPed when it leaves the mill. Yet PaPer wrapping provides only short term protectlon

Wrapping that becomes torn from mishandling should be repaired promptly. Open or closed sheds are favored over outside storage for dry lumber.

To maintain the low moisture content achieved by kiln drying, store high grade items (shop, moulding, millwork) in a closed, heated shed with a clean, paved floor.

For outside storage, yards should be open, without trees or buildings severely hindering airflow. Proper water drainage is needed to prevent standing water from adding to the ambient humidity. Lumber should be stored at least 12" to 18" inches off the ground to allow moist, cool air to move away from the wood. In dry climates, stacks of lumber should be configured perpendicular to prevailing winds to prevent end checking.

Prop", handling should not stop at the yard - but continue at the job site. First, help builders by loading the delivery truck in proper sequence; materials to be used first should be loaded last.

Materials stored at the work site rarely are adequately protected. WWPA advises making a few helpful suggestions to your customers: . Do not place unprotected lumber directly on the ground. Use supports to keep units away from mud and groundwater. This is especiallY important with prefabricated materials (e.g., trusses), which cannot tolerate significant moisture gain.

Protect lumber at the job site with plastic or a tarp, yet leave the ends open to allow moisture to escape and allow room at the bottom of the Pile for airflow. Plastic reaching to the ground acts like a greenhouse, trapping moisture and promoting decay. Set appropriate delivery sched- ules to keep the lumber arriving as needed at the work site. but avoid unnecessarily lengthy storage in uncontrolled environments. Always store paneling, moulding and millwork indoors on supports, with good ventilation, and keep these materials away from newly poured concrete or freshly drywalled surfaces, where humidity is significantly higher.

Allow sufficient time for acclimation. Dry finish materials and siding require seven to l0 days to reach the moisture equilibrium of their new setting before installation. For siding, store the sheets in a covered. unheated area, so it is protected from rain, snow and sun while still able to acclimate to outside conditions. Sticker and store moulding, millwork and paneling in the room where they will be used, with heating and cooling systems operating.

Proper storage and handling is an essential step toward profitability and toward positioning your company as one that provides top quality products.

- For more information, copies of the Lumber Storage TIP Sheet are 506 each from the Western Wood Products Association, 522 SW 5th Ave., 4th Floor, Portland. Or.97204.