What you should know about pressure treated wood

IIRESSURE TREATED lumber

F- is a building material with a wide range of applications.

The following is a series of questions and answers designed to bring to light more information on pressure treated wood and its properties.

Q: What is pressure treated wood?

A: Pressure treated wood is wood that has been impregnated with a preservative in a process that forces the chemicals under pressure deeply into the wood. The preservatives are locked permanently into the wood and are present in sufficient quantities to deter attack by insects (termites) and decay (fungi).

Q: Will wood used in outdoor landscaping projects be attacked by insects and decay?

A: Yes! Termites are active in many areas. They will attack wood in exposed landscape structures more readily than wood used in interior residential construction.

The heartwood (darker interior portion of the tree) of all woods has some natural durability. The heartwoods of some species, such as redwood and cedar. are more durable than other untreated species, however. this natural durabilitv is extremely variable.

Q: How long will the treated wood last?

A: Pressure treated wood is classified by FHA, Uniform Building Code, and other authorities as a permanent building material. The Forest Products Laboratory of the U.S. Department of Agriculture has concluded wood that has been pressure treated properly can last in excess of 50 years.

Q: Is pressure treated wood safe?

A: Yes. The preservatives are safe for normal contact by humans and animals. These treatments have been used successfully and safely throughout the world for over 4O years.

Q: Is there a marking system for pressure treated wood?

A: Yes. All wood intended for outdoor use should bear the LP-22 mark of the American Wood Preservers Bureau, the quality control agency for the wood preserving industry, or the mark of agencies approved by the building code.

Q: Are there different levels of preservative treatment?

A: Yes. Depth of penetration and amount of preservative injected into the wood (retention) can vary substantially. Different levels are specified depending upon use. For outdoor home projects, two levels of treatment are available. LP-2 wood is treated to a minimum retention of .25 lbs. per cubic foot. This is recommended for above-ground use and definitely should not be used for ground contact. LP-22 wood is treated to a minimum retention of .40 lbs. per cubic foot and can be used in ground contact.

Q: Is there any leaching of the preservatives out of the wood?

A: Essentially none. The preservatives have a low solubility level to water and consequently do not leach out of wood.

Q: What about treatments where wood is sprayed or dipped?

A: Such treatments are not permanent and provide only superficial protection against decay and termites. Spraying and dipping are not approved by the building code.

Q: What are some of the reasons to use pressure treated wood?

A: (f) Pressure treatd wood lasts longer than untreated wood.

(2) Pressure treated wood doesn't need painting or staining, although it will take most finishes.

(3) Pressure treated wood costs less than heartwood grades of redwood and cedar sold for yard and landscaping use.

(4) Pressure treated wood looks good. It weathers to attractive light shades of green/brown and darkens substantially less than untreated woods.

(5) Pressure treated wood protects against termites and dccay and reduces slipperiness frequently associated with untreated wood.

(6) Pressure treated wood can be used in contact with the ground and is approved by the building code for this use.

(7) Pressure treated wood is specified by a large and ever increasing number of architects and engineers for dependability.

(t) Pressure treated wood helps save our forests by lengthening the useful life of wood structures. Treated wood utilizes species that are readily available.

(9) Pressure treated wood avoids costly replacement costs.

Pressure Treated

(Continued from page 9) glulam: pressure-treated wood is used wherever wood is to be placed in the ground, in water, in contact with masonry, or where exposed to wetting or corrosive environments. It is also recommended for hot, humid climates and wherever untreated wood is susceptible to decay or termites.

Pressure-treated poles provide design solutions to many building problems. Site preparation is less involved and, therefore, Iess costly than methods involving bulldozing and excavating. Expensive footings and costly foundations are eliminated. Walls and partitions are nonloadbearing, providing maximum utility in interior space. Remodeling and adding-on are simple; prefabricated modules are readily accepted. As documented bY the USDA, pole frame houses and buildings exhibit exceptional resistance to storms, hurricanes and earth shocks and tremors.

Pressure-treated timber piling in the U.S. has a documented service life of nearly 100 years, with no record of failure. Pressure-creosoted timber piles were among the first used (1890) in foundations for permanent structures where pile heads project above the ground water line, or where future subsidence of the water table may expose the piles to alternate wetting and drying.

Load tests have been carried to nearly 235 tons. First cost of timber piles is lower than other materials. They can be driven faster. They can be cut off and ready for the footing cap immediately.

Fire-retardant treatments are proprietary formulations required to have a performance rating in struc- tural lumber (AWPA C20) and plywood (AWPA C27). Material shall have no greater flame spread than 25 when tested in accord with ASTM E'84 and when the test is extended to 30 minutes duration it shall have no greater flame spead than equivalent of 25 and no evidence of significant progressive combustion.

Pressure-treated wood meets fire safety requirements. Impregnated with special chemical formulations, fire-retardant treated wood (FRTW) reacts automatically when attacked by flames. At temperatures below the normal ignition point of untreated wood, the FR chemicals release noncombustible gases and water vapor, retarding combustion and causing the wood surface to form a hard layer of insulating carbon char.

Without a fuel source fireretardant wood will not burn. Under fire conditions it can support design loads over long periods of time, in many cases longer than unprotected steel, giving firefighters added time to fight the fire and perhaps to save lives. FRTW shakes and shingles are rated as Class "B" or "C". In general, FRTW qualifies for greatly decreased insurance rates when compared to untreated wood.

Southern Pressure Treaters Association (SPTA) is a non-profit association that disseminates information about the proper use of pressure-treated wood. Our home office is at 2920 Knight Street, Suite l2l, Shreveport, La. 7l 105.

Our association is made uP of 4l companies representing a total of 68 plants throughout the l5 states in the Southern pine area, with annual pressure treatment of over 100 million cubic feet of Southern pine poles, piling, fence posts, lumber and Southern oak and mixed hardwood cross and switchties.

SIX at the Slaughter Brothers, Inc. booth at the show included (1) Kerry Kennedy, Tim Thompson, Michael Dearing, Fred Renner, Bill Franks, Roy Enyeart. (2) Bob Guthrie, Ken Johnson. (3) Neil & Kim Bowie, Burt & Marsha Solt. (4) Jim White, Sherry Carroll, LeRoy Jordan. (5) NLBMDA's John Martin. Jack Summers. (6) Southwest Forest In- dustrie's David Leland, Melvin Follis, W.R. Fitzgerald. (7) Duncan Gillies, W.J. Cook, Fred P. Garney. (8) Claire & Doug Ashy. (9) Ken Johnson, Jim Gentry. (10) Jack Delpapa, Richard Urich, Tommy Joyce. (11) Tony Gennusa, Darryl Motley, Tim Bean, Ron Martinson, Gene Lunslord. (12) Berl Harris, Donald Smith. (13) Charles Schulze,

George Natsis, Harmon Goins. (1f) Hugh Thompson, John Prizer, Jerry Minter. (15) Al Hart, Cheryl Huggins. (16) Mike Gulledge, Jim Bryce, Bubba Lammons. (17) Robert Randall, John Kurnik, Nick Morris. (18) Jim Brandstener, Dick Grazier, Pat Tyler. (19) W.C. Fulton, Harold Schweiss. (20) Brian Wier, E.Z. Hunt, Ted Carmack.