• Colour and preservative protection in one step

• A finished project from the start - no need to initially stain

• Proven product performance with the longest lasting colourant on the market

• Works in unison with the CA and ACQ environmentally advanced preservatives

• DesignWood with CA or ACQ penetrates deep into the wood for more protection.

• CA and ACQ preservatives are made from 100% recycled copper.

• Commercialized in the United States in 1992, ACQ earned the U.S. Environmental Protection
   Agency’s Presidential Green Chemistry Challenge Award. Its widespread use in North America and
   Europe eliminated the use of CCA in residential use.

• ACQ is CSA approved and has provided proven protection in Canada in severe environments

  since 2002.

• CA and ACQ with DesignWood meet requirements of National Building Code of Canada (NBCC).

• Ideal for Decks, Fences, Trellis’, Docks and Playsets

• Lifetime Limited Warranty against termites and fungal attack

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

• Allow treated wood to dry prior to application - typically around 60 days after installation. Test the
  wood with a few drops of water to see if the wood is dry enough to readily absorb water, then test a
  small portion of the deck.

• Apply a water repellent sealer at least every two years to keep your project looking great.

• Butt boards tightly together during installation as they will shrink slightly in width and thickness as
  they dry out.

• Pre-drill holes about 3/4” from the edges 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.

• Keep your outdoor living space looking its best with the right cleaners and sealers to
  enhance its long-term beauty.

• Liquid detergents, water and a stiff bristle brush will remove most mildew and dirt.

• Always follow the manufacturer’s mixing and application instructions.

• Never use household chloride bleaches on wood as it can cause damage to the wood

  fibers and fasteners.

• Care should be taken if a pressure-washer is used for cleaning, as excessive pressure may
  cause damage to the wood.

While there is scientific consensus that treated wood can be used for garden and

vegetable beds, the information below explains what chemicals are used in Viance

ground contact treated wood for residential use and the results of numerous

scientific studies.

Viance treated wood for raised garden bed

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 is widely

available under the brand name Preserve® from 84 Lumber and independent

lumber dealers across North America.

CA and ACQ preservatives contain copper, the primary fungicide and termiticide in Viance’s ground contact product. The fungicide prevents soil fungus from attacking the lumber and works to deter insects, including termites. Copper is also a common fungicide for food crops used by consumers for growing vegetables and is a disinfectant in swimming pool chemicals.

Of interest to the home gardener is whether any of the preservative components in treated wood used to construct a raised bed garden could render the food crop unsafe for consumption. The available evidence suggests no. John Harrison, President of JRH Toxicology, a consulting firm specializing in scientific advice to the industry and government, writes in 2017 that CA and ACQ have been carefully evaluated for safety and registered by the Health Canada Pest Management Regulatory Agency (PMRA) for use in residential construction applications. He stated in a bulletin titled, Treated Wood in Raised Bed Gardening, “Scientific evidence and data have shown that using pressure treated wood for raised bed or box gardening is safe to adults and children in terms of the plants grown and used in these containers.” He further explains, “All chemicals in consumer products have a toxicity and most are very low, so they are not a problem, especially those regulated by the federal government. This is also the case with currently registered wood preservatives that contain copper. In fact, small amounts of copper are necessary for human and plant life and termed “an essential trace element”.

Dr. Scott Leavengood, Associate Professor College of Forestry at Oregon State University and Director of the Oregon Wood Innovation Center authored an article for the OSU Extension Service, titled “Raised bed lumber, pressure treated safe?” In this article, Leavengood gives his opinion that the consensus among researchers is that the low levels of chemicals in preservative treated wood that leach out of the wood into the soil are likely to be taken up by the plants only in very small amounts. There has been no evidence to suggest that the level of the chemicals is significant enough to be of concern for human health.

In a 2014 study, wood research scientists Love, Gardner and Morrell at Oregon State University found that in growing radishes, carrots and potatoes in a copper azole treated Douglas-fir planter, the copper levels were not higher in roots or tubers of radishes, carrots or potatoes compared to beds constructed from untreated wood. They also state that when people are concerned about the migration of wood preservatives, they can use polyethylene (plastic) to line the inside of the planter. Their scientific results indicate that although plastic lining is “not entirely necessary”, it can be used if there are safety concerns. The use of a plastic barrier will also extend the life of the preserved wood and help keep the raised bed garden soil within the bed area. For proper drainage, the plastic material should not be used underneath the raised bed garden.

Safe practices for working with treated wood recommend treated wood not be used where it may come into direct or indirect contact with drinking water or a component of food, animal feed or beehives. The USDA prohibits treated lumber for soil contact use in their certified National Organic Program published in 2011. The updated draft dated September 5, 2018 states that CA and ACQ are not currently allowed because they are not included on the National List of allowed synthetic materials (7 CFR part 205, page 425).

Viance recommends for those who have concerns to line the interior walls only with heavy plastic sheeting. There have been no justified claims that today’s treated lumber causes any negative effects from leaching into the soil.

Sources:

https://plantcaretoday.com/pressure-treated-lumber-for-a-vegetable-garden.html

https://www.finegardening.com/article/are-pressure-treated-woods-safe-in-garden-beds

https://extension.oregonstate.edu/raised-bed-lumber-pressure-treated-safe

Love, Connie & Gardner, Benjamin & J. Morrell, Jeffrey, (2014) Metal accumulation in root crops grown in planters constructed from copper azole treated lumber European Journal of Wood and Wood Products. 72. 10.1007/s00107-014-0789-5.

https://extension.psu.edu/environmental-soil-issues-garden-use-of-treated-lumber

https://hgic.clemson.edu/factsheet/treated-wood-in-the-landscape/

https://www.woodpreservation.ca/.../Bulletin-Treated-Wood-In-Raised-Bed-Gardening...

https://www.ams.usda.gov/sites/default/files/media/NOP%205036%20Treated%20Lumber%20Draft%20Guidance.pdf

https://www.ams.usda.gov/rules-regulations/organic/national-list