FAQ – Old

• The built-in wood stabilizer keeps boards straighter and minimizes cracking, checking and splitting.
• An environmentally advanced, non-metallic preservative, HiLine Treated 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 above ground applications six inches or more off the ground.

• 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.

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

• 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.

• 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.

• 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.

• For exterior project applications, treat all field-cut ends of boards and drilled holes with a brush-on wood preservative. Copper naphthenate formulations are available from home centers, lumber dealers and hardware stores. Deck stains and sealers do not provide adequate protection.
• 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, no closer than 1/2″ from board ends or sides, to help prevent splitting.
• Use screws to improve holding performance.
• Install fasteners flush to the wood surface. Do not overdrive fastener.
• Install the un-cut end of support posts in ground contact applications.

• 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.

• 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, 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. 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.

The construction of an in-ground, raised vegetable garden should use materials designed to withstand ground-contact exposure. Treated wood labeled for ground contact can be used to build to build raised beds for edible garden plants. Above ground contact labeled wood, is not intended or approved for ground-contact exposure. HiLine Treated pressure treated for ground-contact exposure, can be used around edible plants, and is available in 2×8’s and wider as well as larger posts such as 4×4’s or 6×6’s which may work as the retaining wall or perimeter of a raised vegetable garden.

Pressure treated wood is the application of a preservative formulation that is forced into the wood under pressure in a large cylinder. AWPA treatments are a safe and proven means to preserve and protect outdoor wood from decay and termite attack. Pressure treatments extend the life of wood, and reduce the impacts on forests, making them truly one of the most sustainable building materials used in the world today.

Wood products for construction are typically treated in a factory, using a pressure process. The product is loaded into a cylinder, and then the cylinder is filled with a solution containing the preservative chemicals. The vessel is pressurized to force the solution into the wood. Most dimensional lumber, as well as plywood, can be treated this way.

Wood is an environmentally sound, economical building material that can be used either indoors or outdoors for a wide variety of structural and decorative applications. Unfortunately, untreated lumber cut from most commercially harvested tree species is subject to attack by insects or to decay caused by fungi and bacteria. The decay or insect hazard is greatest in exposures where the wood is subjected to moisture. Wood in outdoor exposures, either in ground-contact or in above-ground applications, is susceptible to attack. The potential for wood deterioration is greatest in hot and humid climates, which allow insects, fungi and bacteria to thrive. Destruction of untreated wood in aquatic environments can be caused by a variety of marine organisms. Wood should be treated with a preservative system to control the destructive activities of these organisms and ensure long-term structural soundness and serviceability.

Lumber that has been treated to AWPA above-ground retention levels (UC3B) is standardized to provide a level of performance that is appropriate for above-ground applications. Proven above-ground products that meet the AWPA standards have historically performed well without the excessive use, or potential costs, associated with increasing those preservative levels for high-decay/ground contact level treatments.

No. All treated wood is not the same.

Above ground treated lumber is code compliant for use in applications where the wood does not touch the ground (e.g. deck joists and support beams used as critical structural members, decking, railings, and above ground fence pickets), or when use is six inches or more from the ground.

Wood treated to ground contact levels is required for direct contact with the ground (e.g. fence posts, etc.), and in cases where a high-decay hazard is very likely to occur (e.g. soil/leaves/debris build-up or accumulations are left to remain in contact with the wood, poor ventilation, tropical climates, etc.).

In this economy, everyone is looking for ways to save money and stay in business. The building products industry is no exception. With increased competition for sales and market share, lowering the quality of products or services is one way to save money. While a reduction in cost and quality might help some organizations survive on a short-term basis, it can have unintended long-term consequences. For this reason alone, it’s important to provide high-quality products and services to the public to maintain the trust of the customer to gain repeat business and positive referrals. AWPA has been the premier developer of consensus-based standards for treated wood products since 1904, which is why the building codes rely on AWPA Standards.

There are naturally-occurring fungi in the ground that attack lumber, so lumber destined to be used in the ground must be treated to a higher standard, or retention level, of fungi-resistant preservatives in the wood. The end tags on treated lumber will provide you with proper use designations. Look for Above Ground or Ground Contact on the end tag.

Retention levels refer to the amount of preservative retained in the wood following the treatment process. Retention levels can be different based on the wood preservative system used to pressure treat the wood product and its intended end use (ground contact, above ground contact, etc.). It is recommended to purchase treated wood products for the intended exposure condition. Typically, wood products are treated for “above ground use” and “ground contact use”. The treated wood end tag should state the recommended end use for the treated wood product.