FAQ

Lumber's greatest enemy is biological attack — destruction by termites, fungi and marine borers — as well as damage from rain, sun and wind. Thanks to over 50 years of research, ProWood^® can stand up to every threat for decades of use.

Another common preservative is a solution containing natural, environmentally safe mineral salts called borates. Borate lumber has a powerful termite-resistant barrier — even the extremely destructive Formosan termite. The new generation of pressure-treated wood uses micronized copper as a preservative. This method enables ProWood to resist termite damage and fungal decay.

Micronized copper preservatives help protect ProWood against termite damage and fungal decay. This preservative system features an innovative technique in which copper is milled into sub-micron-sized particles. These copper particles are then suspended, instead of dissolved, in the wood preservative solution used during the pressure treatment process. Micronized copper eliminates the need for a solvent, which is required in other treatment methods. As a result, ProWood delivers better performance, better corrosion properties, and has a fresh, more natural appearance. To learn more, visit our MCA page.

Look for a lumber end tag. Each piece of ProWood lumber has a tag containing information regarding the preservative used, the appropriate end use (i.e. above-ground or ground contact), the quality standard and safe handling instructions. To learn more, visit our Understanding the End Tag page.

ProWood treated wood is very safe when used as directed in the appropriate applications. The preservative injected reacts with the wood to form an insoluble complex that won't evaporate or vaporize. ProWood is clean, odorless, non-staining, and safe to work with and handle. Its built-in protection is non-irritating for dermal contact with children, adults, animals and plants.

We have carefully studied the minute amounts of preservative released during a ProWood structure's serviceable lifetime. ProWood is safe long-term for the environment and for contact with people and pets. ProWood MCA treated wood — as with any wood product — should not be used where household pets would be likely to chew or ingest the wood. The process used to treat ProWood is the first to gain Environmentally Preferable Product (EPP) as certified by Scientific Certification Systems (SCS). Scientific Certification Systems is a third-party certification services and standards development company. According to the EPA, to be EPP certified means that the product has a reduced impact on human health and the environment when compared to other products that serve the same purpose.

ProWood lumber attaches end tags to ensure that our customers know key information about the product. The tags can include information about available warranties, whether or not the product is for direct ground contact or strictly above-ground applications and, where applicable, details for acceptance by local building codes. Many of the tags on ProWood products also have detailed information on the safe handling of ProWood, the same information contained in the warranties.

No. Most commonly this is heartwood, which is naturally decay resistant. You do not need to be concerned. With the exception of some western species, these end cuts do not require any special treatment. Refer to the ProWood Warranty for more details.

According to AWPA's Standard M4-06, lumber and timber that are used in above-ground applications and are of sapwood species such as Southern, red or ponderosa pine, generally do not require treatment to provide a good service life. This category includes most ProWood lumber and products. Other heartwood species typically found in the western U.S. should be field treated when cut or drilled. If you are concerned about wood exposed after cutting or drilling, you can use a brush-applied preservative. Home centers and lumberyards often carry brush-applied preservative systems based on two different active chemicals: either copper naphthenate or IPBC (3-iodo 2-propynyl butyl carbamate). These systems should be applied in accordance with their labels to any surface exposed by damage or field fabrication. Users should carefully read and follow the instructions and precautions listed on the preservative system label when using them.

Look for a lumber end tag. Each piece of ProWood lumber has a tag containing information regarding the preservative used, the appropriate end use (i.e. above-ground or ground contact), the quality standard and safe handling instructions. To learn more, visit our Understanding the End Tag page.

ProWood treated wood is very safe when used as directed in the appropriate applications. The preservative injected reacts with the wood to form an insoluble complex that won't evaporate or vaporize. ProWood is clean, odorless, non-staining, and safe to work with and handle. Its built-in protection is non-irritating for dermal contact with children, adults, animals and plants.

We have carefully studied the minute amounts of preservative released during a ProWood structure's serviceable lifetime. ProWood is safe long-term for the environment and for contact with people and pets. ProWood MCA treated wood — as with any wood product — should not be used where household pets would be likely to chew or ingest the wood. The process used to treat ProWood is the first to gain Environmentally Preferable Product (EPP) as certified by Scientific Certification Systems (SCS). Scientific Certification Systems is a third-party certification services and standards development company. According to the EPA, to be EPP certified means that the product has a reduced impact on human health and the environment when compared to other products that serve the same purpose.

Your climate will affect when and how often wood sealer needs to be applied. To maximize surface protection and to keep your deck looking good, apply a quality wood sealant that contains an ultraviolet stabilizer.

Know when to apply a wood sealer by dripping water onto the deck surface. If the water quickly absorbs into the wood, it's time to apply a wood sealer. If the water droplets bead up, your deck is protected. Be sure to test annually.

Although ProWood provides a surface that is easier for paints to cover, we do not recommend painting it. ProWood does not need protection from the elements. But if your decorative decisions call for paint, make sure the wood is dry before application. (Pour some water over the surface. If it beads, wait; if it seeps into the wood, it's ready to paint.)

No. Landscape timbers (unlike 4×4 pressure-treated dimensional lumber and 6×6 pressure-treated timbers) are not recommended for use as a structural post because they are not treated for ground contact and do not carry a lifetime limited warranty.

Similar to pressure-treated deck boards, some shrinking will occur as the pickets dry. Butting pickets together during installation will minimize the gap left between the pickets when they dry.

Yes, ProWood may be used indoors for any application except cutting boards and countertops.

You should always consult your local building codes before application. When working with ProWood pressure-treated decking, lumber and timbers, you'll want to locate the double-box symbol on the end tag. The double-box symbol is required for building code compliance; indicating the standard authority and the third party inspection agencies. Generally, ProWood decking, lumber and timber products will carry the double-box symbol demonstrating that they are code compliant when used in the right application.

Picnic tables are primarily used for serving pre-prepared food, while a kitchen countertop is used primarily for preparing food and often as a cutting surface for raw food.

Yes. Treated timbers used to construct raised vegetable gardens and flowerbeds are popular and practical. Scientific tests have proven there is no significant uptake of preservatives into plants. And treated wood used for tomato stakes, flowerbed edging, planters, retaining walls, trellises and compost bins have the added advantage of lifetime durability.

If you intend to install an under-deck ceiling system, the general guidance is that the homeowner/builder must ensure that the ceiling system is well ventilated, drainage systems have proper slope and the system prevents debris from accumulating. The homeowner must use building code compliant ground-contact treated materials (UC4A) for all parts of the structure, including the decking. Systems with poor ventilation (or no ventilation) should not be used, as even ground-contact pressure-treated lumber may not provide adequate service life.

Yes. Our tags will always state "above ground only" or "ground contact" so you can be sure you are using the right material for the job. ProWood products containing higher levels of preservatives are available for special purposes such as projects requiring extensive moisture/earthen contact –– including foundations, pole barns, docks and culverts. For more details, refer to the Understanding the End Tag page.

Ultimately, your deck boards should have an edge gap between ¼ inch and ⅜ inch to allow for proper ventilation and for debris to pass through. However, most pressure-treated lumber decking that is sold through lumberyards and box retailers has high moisture content (meaning it’s wet) — so the boards are swollen. Always butt wet boards tight against each other or leave a minimal gap. Your wet deck boards will contract and create a wider gap as they dry. This could happen in a relatively short period of time (days to weeks) or may take longer depending on your climate and exposure to the sun.

If the wood is dry or has been kiln dried, such as ProWood Kiln Dried, install deck boards with approximately ¼ inch gap to allow for proper ventilation and for debris to pass through. Wet or dry boards should be installed tight end-to-end.

Note: Each piece of lumber is different and the change in width can vary as each board dries.

Yes, when you follow a few guidelines, outdoor enclosures for animals are an appropriate use for ProWood lumber. For ponds, make sure to choose lumber that is treated to the proper retention of preservatives in the wood. The lumber end tag should note the end use as "Ground Contact/Freshwater Use." A small amount of leaching takes place, and copper that's used in most pressure-treated lumber does have aquatic toxicity. Generally, however, the levels of leaching will only be problematic in situations where there is a large amount of treated wood compared to the volume of water and where there is a low water flow. For more information, the USDA Forest Product Lab discusses treated wood and environmental impact.

ProWood is designed to give professional-grade results that last. Left unfinished, it ages gracefully, eventually softening to an attractive driftwood gray. On flat surfaces such as decks, however, leaves and other debris may collect and create unsightly stains. Even if your lumber has the locked-in protection of factory-applied water repellent, you'll want to follow an annual maintenance program that includes a semi-transparent stain or a sealant that contains an ultraviolet stabilizer. If you stain your project, a quality penetrating latex or oil base stain is recommended.

The process used to treat ProWood is the first to gain Environmentally Preferable Product (EPP) status as certified by Scientific Certification Systems (SCS). Scientific Certification Systems is a third-party certification services and standards development company. According to the EPA, to be EPP certified means that the product has a reduced impact on human health and the environment when compared to other products that serve the same purpose.

The Home Innovation Research Lab authorizes accredited verifiers to award points toward project certification under ICC-700 National Green Building Standard. ProWood uses wood preservative technology from Koppers. ProWood has earned Green Approved Product Certification from the National Green Building Standard (NGBS). By using ProWood products, architects, specifiers, homebuilders and contractors are eligible to receive points toward a building being certified under the National Green Building Standard.

The GREENGUARD Gold Certification is awarded to products that are intended for use in schools, daycares or other locations where children spend large amounts of time. The certification shows that a product adheres to the highest standards for chemical emissions, ensuring public safety regardless of age.

ProWood FR fire-retardant treated lumber is typically specified for use in areas not exposed to the weather or wetting and where the adopted building code permits the use of wood or fire-retardant treated wood. ProWood FR fire-retardant treated wood is typically permitted for interior, above ground applications such as: roof systems, studs, flooring, joists, sill plates (when not in direct contact with the ground), blocking and furring, and other interior applications.

Yes. As indicated in our literature and confirmed herein we support the use of ProWood FR in sill plate applications.

Yes. Under normal temperature and humidity conditions, latex and oil-based paints, as well as water- and solvent-based stains, can be used with ProWood FR treated wood. If prolonged exposure to high humidity conditions is expected, special surface preparation procedures including the use of an appropriate primer are recommended. Before applying any finish, the wood surface should be lightly sanded, cleaned and dry. For best results, always follow the coating manufacturer’s label instructions.

For a period of 50 years from the date of installation, reasonable cost of repair is covered for products that suffer strength loss below the values published in ESR-4373, subject to the terms and limitations spelled out in the ProWood FR Warranty.

UL GREENGUARD Gold Certification for ProWood FR confirms that it does not contain urea or formaldehyde as an active ingredient or inert component, and it does not release volatile organic compounds (VOCs) as defined in UL’s test procedures.

ProWood FR must be stored off the ground and protected from weather to prevent loss of the protective chemical treatment. Likewise, exposure during construction should be minimized. If some exposure occurs, the material must be allowed to dry to its original specification before being covered.

Galvanized steel hardware is recommended for use with ProWood FR wood. Even though the ProWood FR treatment does not increase corrosion of bare or galvanized steel, galvanizing provides an added level of protection with any treated wood product. The following metal fasteners are compatible with ProWood FR wood and are outlined in ESR-4373: 2024-T3 aluminum, SAE 1010 steel, hot-dip zinc galvanized steel, copper or red brass.

Yes. All code-recognized pressure-treated fire-retardants have some decrease in certain strength values. The correct adjustment factors for ProWood FR are published in ESR-4373.

Yes. ProWood FR meets all of the applicable code requirements for use in the U.S. outlined by the IRC and IBC.

Cutting to length, drilling and diagonal cuts as well as light sanding are permitted. Ripping dimensional lumber is not allowed.

No. The reference to pressure treatment for ProWood FR is to convey that the product is manufactured to the highest standards and is fundamentally superior to other products found in the market that have some type of dip or spray-on treatment. ProWood MCA or other preservative-treated products in the ProWood family should be used where protection from decay or termite attack is needed.

Yes, through Koppers Performance Chemicals, our preservative supplier. The Osmose program is unique within the treated wood industry because it offers AIA professionals the opportunity to receive credits under the Sustainable Design (SD) CE requirement as well as GBCI CE requirements for all LEED Professionals.