FAQs

Why use ProWood pressure-treated lumber?

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.

What preservatives are used for pressure treating ProWood and how long are they effective?

For a long time, CCA (Chromated Copper Arsenate) was the primary wood preservative. CCA-treated wood protects against all major forms of destructive attack and is effective for many years. More recently, preservative manufacturers switched to ACQ (Alkaline Copper Quaternary). ACQ is also effective for decades, reducing demands on forest resources. Another common preservative is a solution containing natural, environmentally safe mineral salts called borates. Borate lumber has a powerful barrier against termites — even the extremely destructive Formosan termite. The new generation of pressure-treated wood uses micronized copper as a preservative. This method enables ProWood to stand up against termite damage and fungal decay.

How do you treat ProWood with micronized Copper?

Universal Forest Products utilizes a treatment method developed by Koppers (formerly Osmose), which uses micronized copper preservatives to 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.

How do I know if the treated wood I'm using is properly treated for my intended use?

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.

In some cases, building code regulations mandate the use of treated wood that meets certain standards. The International Code Council (ICC) develops model building codes for use nationwide. ProWood has been determined by the ICC-ES to be code compliant with the details listed under the ESR-1980 Report (pdf – 257 KB), ESR-2240 Report (pdf – 309 KB) and the ESR-1721 Report (pdf – 107 KB). In the case of treated wood, the ICC relies primarily on the American Wood Protection Association (AWPA) to determine appropriate standards of treatment for specific preservatives in specific end uses. They also offer their own ICC Evaluation Service as a way to determine if a product is suitable. Quality control measures are designed to ensure the treated wood produced meets the quality standards. In addition to in-house quality checking, manufacturers are also required to subscribe to an independent inspection agency, which verifies the wood was treated in accordance with the applicable standards. Manufacturers who are in good standing with the third party inspection agency will carry that agency's quality mark on the lumber end tag.

For an independent viewpoint on how to tell if your wood is properly treated, view the USDA's Forest Products Laboratory TechLine on new wood treatments.

How does ProWood treated with micronized copper differ from ProWood Borate and ProWood ACQ?

Micronized copper particles in ProWood MCA treated lumber bond permanently to wood cells causing less corrosion in fasteners and giving the wood a lighter, fresher appearance after treatment as compared to ACQ and Borate.

When is special handling required?

Our warranties outline specific handling tips.

The most important precaution is DO NOT BURN TREATED WOOD. When pressure-treated wood is burned, the preservative chemicals concentrate in the ash and may be inadvertently inhaled. Wear gloves when handling treated lumber, and always wear safety goggles and a dust mask when sawing or cutting treated lumber, just as you would with untreated lumber.

When should I apply wood sealer to pressure-treated lumber decking?

Climate change 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.

How safe is ProWood?

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 and exhaustively studied the minute amounts of preservative released during a ProWood structure's serviceable lifetime. The conclusion is clear: ProWood is also safe, long-term, for the environment and for contact with people and pets. In our opinion, 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.

What does it mean to be a Certified Environmentally Preferable Product (EPP)?

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.

What does it mean to be a NAHB Green Approved Product?

Green Approved Products are products that the NAHB Research Center has approved as eligible to contribute points toward certification of a building under the National Green Building Standard. ProWood uses wood preservative technology from Osmose, Inc. ProWood has earned Green Approved Product certification (pdf – 633 KB) from the National Association of Home Builders (NAHB) Research Center under the National Green Building Standard Program. 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.

What is the GREENGUARD Children & Schools Certification?

The GREENGUARD Children & Schools Certification is awarded to products that are intended for use in schools, day cares 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.

Do you recommend painting ProWood treated wood?

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.)

Can I use pressure-treated landscape timbers as a fence post or deck post?

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.

Should I space my pressure-treated wood fence pickets during installation?

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.

Can ProWood be used indoors?

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

Is ProWood pressure-treated wood Building Code approved?

ProWood pressure-treated wood is Building Code approved for use in decking and above-ground applications.

Why can I use ProWood for a picnic table but not a countertop?

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.

Can ProWood be used for gardening?

Yes. Treated timbers used to construct raised vegetable gardens and flowerbeds are increasingly popular and practical. Recent scientific tests prove 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.

Is it okay to install an under-deck ceiling system to my elevated wood deck?

If you intend to install an under-deck ceiling system, UFP’s 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.

How do I remove the ink stamp from my ProWood pressure-treated lumber?

The ink used for marking pressure-treated lumber grades (applied at the lumber mill, not a UFP pressure treating plant) is a water-based ink that will naturally disappear over time from weather and foot traffic. Some builders and DIYers speed up the process by scrubbing it with soap and a scouring pad or soft bristle brush. This process will help reduce the contrast, but will not totally eliminate the mark. Always test in an inconspicuous spot or on a scrap piece of lumber. Consider the same treatment for pencil marks.

What is the significance of the tags stapled to my lumber?

Universal Forest Products attaches end tags to all of its ProWood lumber 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.

Are there different types of ProWood for different applications?

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.

Are there any fastener recommendations when building with ProWood?

There's no need for special, expensive fasteners. You can also use hot-dip galvanized connectors, such as G60 connector plates or other fasteners and connectors as recommended by building codes; otherwise, your treated wood will last longer than the unprotected fasteners you've used to put it together. 

Aluminum building products can be placed in direct contact with ProWood MCA treated wood products used for interior applications and above-ground exterior projects such as decks, fencing and gardens.

For more details on fastener compatibility, view the Fastener Recommendations page and the ProWood Fastener Advantage (pdf – 133 KB).

Should I space my pressure-treated deck boards during installation?

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.

I cut the end off of my ProWood lumber, and it looks like the middle is untreated. Do I have a bad piece?

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.

Brush-on Preservatives for Field Cuts

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.

Is it safe to use ProWood lumber for animal enclosures such as bird feeders or fish pond retaining walls? I have heard that leaching may be a problem.

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 preservative 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.

After my project is built, is any special maintenance necessary?

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 semitransparent stain or a sealant which contains an ultraviolet stabilizer. If you stain your project, a quality penetrating latex or oil base stain is recommended.

Does ProWood qualify for continuing education learning credits?

Yes, through Osmose, 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.

The course is offered through AIA Education Provider, GreenCE, Inc. Credit for this course is 1 AIA/CES LU/HSW/SD Hour and 1 GBCI CE Hour for LEED Professionals. To review the course and take the online quiz for CE Credit, please visit: http://www.greence.com/cgi-bin/info.pl?action=course&id=93.