🚧 Ask the Experts - Questions & Answers | Treated Wood

Ask the Experts - Questions & Answers

  • Can you use pressure treated lumber for raised garden beds?
    Raised Vegetable Beds

    While there is scientific consensus that it is safe to use for vegetable/garden beds, the information in this article explains what chemicals are used in Viance ground contact treated wood for residential use and the results of numerous scientific studies. 

    The American Wood Protection Association (AWPA) specifies the use of treated lumber for horticultural purposes to be Ground Contact. In the AWPA Book of Standards, copper azole (CA) and alkaline copper quaternary (ACQ) are listed preservatives for Ground Contact use in residential applications. CA and ACQ are both available from Viance under the brand name Preserve.

    Continue reading scientific studies at this link.

  • Is the D-Blaze fire retardant treated wood FSC certified?

    D-Blaze does make wood products FSC certified.   

    Viance Ask the Experts logo

    D-Blaze treating is a process that does not affect the sourcing of wood products and therefore has no effect on FSC certification.

    The D-Blaze treating process is considered just a stop in the supply chain. As long as the wood substrate being treated is FSC certified, a stop at a treating plant for the D-Blaze pressure impregnation process will not break the chain of custody as long as the requisite tracking of the material through the process is adhered to.

    The important thing is that the vendor of the D-Blaze treated material can supply the FSC certification upon delivery of the treated product and the product is marked appropriately.

    Additional information can be found below.


    If you have any questions please feel free to contact me.


    Todd Schoffstoll

    Western Regional Manager

    Viance, LLC

    704.340.3376 | tschoffstoll@viance.net

  • Do I need to treat the cut ends on my fence posts?

    I just got a fence installed with ground contact pressure treated 4x4 posts. I think it is your Preserve. Do I need to treat the cut ends of the posts? They look to be green all the way through but I wanted to be sure.  

    Construction projects necessitate the need to cut and drill into wood. Building codes and the American Wood Protection Association (AWPA) Standard M4-15 require "all cuts, holes and injuries such as abrasions or holes from removal of nails and spikes which may penetrate the treated zone shall be field treated." The extra effort protects the longevity that the preservatives offer.

    Copper naphthenate is one of the most used preservatives for cut ends and holes. The minimum recommendation is 2% copper metal with 1% copper naphthenate appropriate in those regions of the country where the higher concentration material is not readily available.

    Treating cut ends of lumber
    Photo courtesy of preservedwood.org

    Another two preservatives, oxine copper and inorganic boron can be used for field treating in above ground applications. Oxine copper can be used for applications originally treated with oil-borne or waterborne preservatives. Oxine copper preservatives, containing the recommended minimum .675% oxine copper (0.12% copper metal), are available colorless or in various colors and have little odor, according to preservedwood.org. Inorganic boron can be used in applications originally treated with a waterborne treatment and in areas continuously protected from liquid water.

    These topical preservatives are available in the retail market and can be purchased at local home centers, building material retailers and paint stores who stock products for wood decks or ordered online. Be sure to follow the preservative’s manufacturer's application instructions.

  • Can a fire retardant be added to Ecolife and still be effective?

    The Ecolife treatment does not impart fire retardancy properties to decking. 

    Ecolife decking shown on decking joists

    Unfortunately there isn’t a treatment on the market for both durability and fire retardancy.

    A fire retardant coating will likely wear off over time because it is not pressure impregnated. In addition, building codes do not recognize sprayed-on or brushed-on coatings as code approved fire retardants for wood products; they only recognize formulations that are vacuum/pressure impregnated products.

    Most pressure treated fire retardants are for interior use only, i.e. our D-Blaze fire retardant treated wood product. However, there are some exterior fire retardants available but they don’t increase the weathering, durability, or insect/fungal protection of wood so they are usually only used on naturally durable species of decking like Redwood and Western Red Cedar. The availability is somewhat limited so you would have to check with your local retailer on availability.

    Thank you,

    Todd Schoffstoll, Western Regional Manager

  • Can treated wood be used for sill plates and interior applications?

    Treated wood is intended for exterior use. However, all treated wood material for residential use can be used for indoor, outdoor or in play set construction.

    Example: If the Ecolife product is going to be used 6” above the final grade and will be on a wood subfloor as a sill plate for the stud walls, then EcoLife treated wood is okay to use. Please read the Ecolife installation instructions and adhere to all fastener requirements.

    AQPA Category use Chart for Ecolife Treated Wood

    Example: If the Ecolife treated lumber is going to be used on a concrete slab, then a foam sill seal must be used as a barrier between the concrete and the EcoLife treated wood. We recommend that Dow’s Sill Seal be used to provide this moisture protection. Please adhere to all of Dow’s installation instructions on proper installation. The installation instructions can be found on the product or on data sheets at your local Lowe's retailer. Be sure that the concrete building surface will be above the final grade and all water is diverted away from the slab. If you have any further question please let me know. Thank you again for your inquiry and happy building.

    Jonathan Whitehead, Eastern Region Sales

  • Does Preserve ACQ protect against powderpost beetles?

    This question comes from a homeowner in Washington state.

    Based on a study performed by the International Research Group on Wood Preserveation, ACQ is effective in protecting wood against the Powderpost beetle.

    Michael Merchant, Ph.D., Professor and Extension Urban Entomologist, with Texas AgriLife Extension Service states, "The most commonly infested woods include ash, oak, hickory and walnut." He also explains in an article on the Texas A& M website, that powderpost beetles pose little threat to the structural integrity of most homes because they are framed with softwood lumber, and thus not susceptible to attack. Removing infested wood and replacing it with treated wood will eliminate the problem in most cases.

    Aaron Sooter, Technical Services Representative

  • What are the benefits of Ecolife®/Severe Weather® treated lumber compared to other wood treatments?
    • The built-in wood stabilizer keeps boards straighter and minimizes cracking, checking and splitting.
    • An environmentally advanced, non-metallic preservative, Ecolife (EL2) is extremely effective at .019 pcf retention, a fraction of competing products that use two times the chemicals to achieve adequate above ground product performance.
    • The water repellent stabilizer is a built-in part of the preservative system and not an add-on that can vary by treater supplier.
    • Fights exposure to the sun and rain and is used in building decks, railings, fence pickets, arbors, trellises, joists and beams.
    • Less corrosive to connectors and fasteners and can be used in direct contact with aluminum products, even in continuously wet applications.
    • Unsurpassed in effectiveness with virtually no warranty claims in its history.
    • Designed for applications six inches or more off the ground.
  • What types of nails or screws do you recommend?
    • Use code-approved hot-dipped galvanized or stainless steel corrosion-resistant fasteners and G185 hot-dipped galvanized connectors for exterior use.
    • Do not mix metals. If using hot-dipped galvanized fasteners, use hot-dipped galvanized connectors. If using stainless steel fasteners, use stainless steel connectors.
    • For coastal installations, use code-approved stainless steel.
  • How do I remove the grade stamp on my treated wood deck?

    Light sanding will remove or lighten the grade stamp's appearance.

  • How long do I need to wait to stain or paint my treated wood deck?
    • Allow treated wood to dry prior to application. Test the wood with a few drops of water to see if the wood is dry enough to readily absorb water.
    • Typically, treated wood will be dry and ready for finishing 60 days after installation.
    • Apply the stain to a small portion of the deck to ensure the wood is sufficiently dry.
    • Follow the manufacturer's instructions.
  • What do you recommend I use to stain or paint my treated wood deck or fence?
    • Use a good quality oil-based or water-based stain, or exterior wood water sealant product with UV protection to help prevent the wood from turning gray from exposure to the sun.
    • Apply a water repellent sealer at least every two years.
    • Follow the manufacturer's instructions.
  • What do I use to clean my treated wood deck?
    • Clean annually and keep your deck free from dirt and debris.
    • A solution of liquid detergent and water with a stiff brush will remove mildew and dirt.
    • For hard to clean surfaces, use a deck brightener containing oxalic acid to retain the wood’s natural beauty.
    • Never use household chloride bleaches or foaming cleaners as they can strip the preservatives and damage the wood fibers leaving an unnatural whitewashed appearance.
    • Be careful if using a pressure-washer as excessive pressure may cause damage to the wood.
  • What are important installation tips when working with treated wood?
    • Butt boards tightly together during installation as they will shrink slightly in width and thickness as they dry out.
    • Pre-drill holes at the ends of boards to help prevent splitting.
    • Use screws to improve holding performance.
    • Install fasteners flush to the wood surface. Do not overdrive fastener.
    • For ground contact support posts, install the un-cut ends in the ground.
  • How do I remove mold from my deck?

    Mold that you find on pressure treated wood is not an indication of a fungal attack. Mold can grow on the surface of many products including wood (treated and untreated) due to exposure to moisture. To remove mold from your treated deck, use mild soap and water solution and a stiff brush.

    Mold Growth

    Mold and mildew are present everywhere in our environment, both indoors and outdoors. Mold and mildew need four things to thrive: air, water, temperatures between 32 and 120°F, and a food source, conditions that are common wherever humans live, work, and play.

    The best way to minimize mold and mildew growth is to control water and food sources. When it comes to mold or mildew on wood decking, water and organic matter are the primary conditions that enable mold and mildew colonies to thrive. To minimize these conditions, make sure water has the ability to flow away from the deck surface and areas surrounding the deck to lessen the absorption of water. Ensure there is adequate ventilation between deck boards and underneath the deck surface, so water can rapidly evaporate.

    And since both mold and mildew feed on dead or decaying organic matter, so it is important to keep your deck clean of leaves and debris.

    Cleaning Your Deck

    To minimize mold on your decking, clean your deck as often as needed, at least twice each year. Climate conditions vary in different regions of the country and may necessitate more periodic cleaning.

    Remove leaves, debris, and other organic materials that provide a food source for mold.

    If mold is present, there are many commercial products available for cleaning mold. We recommend commercial cleaners containing oxalic acid. For best results, follow the manufacturer’s instructions and use cleaners within their stated shelf life. Do not mix recommended cleaning products together as harmful chemical reactions could occur.

    We do not recommend household chloride bleaches or foaming cleaners as they can strip the preservatives and damage the wood fibers leaving an unnatural whitewashed appearance.

    To maximize application coverage, remove excessive organic growth or clumps prior to applying the cleaner.

    Coatings for High Mold-Prone Environments

    For environments prone to high mold growth, there are commercially available coatings and finishes that seal the wood surface when applied and they should be maintained per the manufacturer’s instructions.

    • Coatings should be applied within one week of cleaning for best results.
    • Prior to coating, properly clean the decking, rinse thoroughly with water and allow to dry completely.
    • Sweep off any pollen and debris.

    Tips for Minimizing Mold

    • Maintain a deck that is dry and clean.
    • Ensure gutters / down-spouts and dryer vents do not discharge directly on decks.
    • Ensure adequate ventilation under and between decking boards.
    • Minimize water puddles under decks and the use of wet mulch up against the deck structure.
    • Cleaning a deck just after the last of the major pollen events (when your car doesn't change color from the pollen anymore) will minimize the seasonal outbreak of mold and mildew.
    • Periodically rinse off your deck using a garden hose with a spray nozzle, especially after the major pollen events. Skilled professionals may use pressure washers with wide fan tips but in the wrong hands, your deck can be damaged. Exercise extreme caution when using pressure washers.
    • Ensure the gaps between the decking boards remain free of debris so that regular rain showers can remove pollen and organic debris between cleanings.
    • Avoid fertilizer over-spray.
  • What are safe practices when working with treated wood?
    • Wear gloves, goggles and dust mask when working with treated wood.
    • Wash hands thoroughly with mild soap and water after working with treated wood.
    • Do not burn or use treated wood debris as mulch.
    • Do not use treated wood where it may come into direct or indirect contact with drinking water or a component of food, animal feed or beehives.
    • Dispose of treated wood debris in accordance with local regulations.
  • What are the similarities and differences in Viance Preserve CA and Preserve ACQ?

    Preserve® CA and Preserve® ACQ

    Preserve CA-C

    • CA-C is a copper-based wood preservative that has been used to pressure treat wood products worldwide. The first form of copper azole (CBA-A) was standardized by AWPA in 1995 followed by CA-B in 2002. CA-C was first standardized in 2009.
    • CA-C contains a soluble copper component as the primary biocide and two triazole fungicides propiconazole and tebuconazole as co-biocides to help control attack from copper tolerant fungi.

    Preserve ACQ

    • ACQ is a copper-based wood preservative that has been used effectively around the world for over 25 years and was initially introduced in 1987. ACQ was introduced to the US in 1992.
    • ACQ is composed of a soluble copper component and a quaternary ammonium compound (Quat) as a co-biocide.


    • Both are water-based wood preservatives.
    • Viance’s brands, Preserve CA-C and Preserve ACQ are both made from 100% recycled copper and are soluble formulations capable of penetrating deeper in the wood cells. Not all competitors’ products contain recycled copper.
    • Both leave a dry, paintable surface.
    • Because the appearance and performance of CA and ACQ treated wood is very similar, they have been used interchangeably in many instances. It is rare for the average consumer to notice any significant difference in appearance between CA and ACQ treated wood.
    • The EPA states, “These wood preservatives have lower toxicity profiles when compared to older wood preservatives."
    • Both preservatives meet the stringent industry standards of the American Wood Protection Association (AWPA), the leading authority on wood preservation science. Both are standardized by the AWPA for a wide variety of residential, commercial and agricultural construction projects including above ground exposed use (UC3B), ground contact general use (UC4A), freshwater immersion (UC4B), and salt-water splash applications (UC4B)
    • Both are field-tested, proven-to-last, accepted as an industry standard, and are building code compliant (IRC and IBC).
    • Both are NAHB Home Innovation Research Labs Green Certified Products for Resource Efficiency and are eligible to contribute points toward a building’s certification under the National Green Building Standard™ (NGBS).


    • The main difference between the two types of treated wood is the co-biocides that are used to combat copper tolerant fungi. Copper Azole uses a blend of azoles as the co-biocide. ACQ uses a quaternary ammonium compound (Quat) as a co-biocide.
    • The differences are few and any differences typically only affect the producers. When properly produced, the differences in the treated wood are insignificant to the point where the retailer and consumer will not notice.
    • The performance of CA treated wood and ACQ treated wood is basically equivalent when properly treated and used in the correct application. When choosing between CA treated wood and ACQ treated wood, the purchaser should consider the following:
      • Performance history of the treating company
      • Quality of the substrate treated and results of treatment
      • Support available

    Fasteners and Connectors

    CA and ACQ treated wood are in the “excellent range” as defined in the Corrosion Engineering Handbook. Viance provides the following guidelines regarding fasteners used with Preserve CA and Preserve ACQ treated wood:

    • Use building-code approved, corrosion-resistant fasteners and connectors suitable for use in pressure-treated wood.
    • For fasteners, use of hot-dipped galvanized (meeting ASTM A 153) or stainless-steel fasteners.
    • For connectors, use G185 hot-dipped galvanized connectors for exterior applications.
    • For Permanent Wood Foundations and corrosive environments, such as Coastal areas with saltwater spray, use code approved stainless steel fasteners and connectors.
    • CA and ACQ are not suitable for direct contact with uncoated steel or aluminum building products.


    Preserve CA and Preserve ACQ treated wood are covered by a Lifetime Limited Warranty from fungal decay and termite attack when installed in accordance with applicable building codes. See details of their Lifetime Limited Warranty for terms and conditions.

    More Information


    See the bulletin at this link.

  • What is the peel and stick product I use for this FRT application?

    An architect in Alaska asked about a peel and stick product for this application: 

    We have a project where we will use FRT plywood as roof sheathing to attach asphalt shingles (IBC provision allows is use this building type we are designing to). This sheathing well be attached to galv. sheet metal "Z' framing to provide a ventilation pathway. below the sheathing. Our concern it corrosive action between the metal framing and the FRT plywood. I'm thinking about calling out a peel and stick membrane between the metal framing members and the sheathing. Is there a recognized product used for the purpose? 


    There is a peel and stick membrane tape that we recommend for use between metal framing and D-Blaze FRT sheathing. Please see the link below.


    If you have any additional questions please feel free to contact me.


    Todd Schoffstoll, Western Regional Manager

    704.340.3376 (Office and Mobile)