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F|-IAKE a large number of mill curI tailments due to previously depressed prices. Add the rebuilding of Iraq. Then combine with a surge of natural disasters, such as Hurricane Isabel and dozens of forest fires, and you have created what has been called "the perfect storm of demand" for domestic plywood and OSB. Prices are at all-time high, and availability is stressed.

The government's purchaser, the Defense Supply Center, shipped nearly 800,000 sheets of plywood in August alone for deliveries in Iraq, along with 320 truckloads of 2x4,2x6 and 4x4 boards to support Middle East operations, reported Random Lengths.

"Plywood costs have more than doubled in the past three to six months," said Dan Usedom, mgr. of Roselle Building Materials, Roselle, Il. "Lumberyards can't keep these materials in stock for more than a day or two."

The price can add thousands of dollars to the cost of building an average single-family home. Some yards are reporting up to eight weeks of wait time for materials.

Skyrocketing prices

and tightened supply have propelled builders to consider using other materials as an exterior sheathing.

Skyrocketing prices and tightened supply of structural wood panels have propelled builders to consider using other materials as an exterior sheathing, said Bob Palermo, Zechman Supply, Chicago, Il.

Fiberock brand sheathing with Aqua-Tough, manufactured by United States Gypsum Co., is one option for exterior wall substrates on buildinss that are going to be sided, or clad, when finished, according to Palermo.

Don Zeman, nationally-syndicated radio home-improvement host of Homefront, said he doesn't foresee prices going down for quile some tlme.

"I would fully expect more and more builders to turn to products like Fiberock sheathing for applications where a non-structural. economical panel is required," he added.

He does, though, warn builders and contractors that they need to fbllow proper procedures installing these type of products.

Manufacturers say gypsum panels should be handled carefully, and the paper-faced products must be kept from precipitation.

In addition to USG, other primary gypsum board manufacturers include Ceorgia-Pacific Corp. and National Gypsum Co.

Another alternative product to wood paneling is foam sheathing, which the National Association of

Home Building Research Center says is the most insulative of all sheathing. It comes in polystyrene, extruded polystyrene, expanded polystyrene, and polyisocyanurate formulations, depending on the size of paneling needed. and the area where it will be installed.

The two primary advantages of foam sheathing are that it doesn't require corner bracing, since it isn't structural in nature, and it reduces the potential for moisture problems through its higher R-value, lowering the potential for condensation to form in the wall cavity.

However. it has little or no nail holding power, accoring to NAHBRC and the Western Red Cedar Lumber Association, therefore is not recommended to use as a nailing base for cedar siding.

Some builders are using fiber cement panels as an alternative to wood sheathing. Fiber cement siding has a natural wood appearance, and reportedly is sealed to protect against moisture better than other priming systems. Brands include WeatherBoards from CertainTeed, as well as HardiPanel and Cemplank from James Hardie.

A less expensive sheathing option is foil, or paper-faced insulative board, that can be applied in large sheets and doesn't require corner bracing. Foil-faced sheathing products include EnergyBrace by Ludlow Coated Products and Thermo-Ply by Simplex Products.

Many of these alternatives require measures be taken to prevent shears in walls.

Nonetheless, APAThe Engineered Wood Association emphasizes that, even at historically higher prices, structural wood panels are a good value.

Its strength and stiffness properties, high perfbrmance as a nail base for finishing siding materials, elimination of the need for let-in bracing, high impact resistance, ease of installation, and proven durability in all climates are benefits of natural structural wood.

NAHB's Research turninq to lor sheathinq are Georgia-Pacif ic's Dens-Gold

Center echoes the APA, saying switching to other products can cause problems related to application, structural limitations, and material characteristics, which impact thermal and moisture performance.

The NAHBRC found the structural wood panel sheathing market share has risen from 357o in 1998 to more than 60Vo today.