Pressure-treated wood is a popular choice for outdoor construction items such as decks, porches, playgrounds, pergolas, and fences, as it resists moisture, rot, and insects. However, the chemicals used to preserve the wood can react to metals, causing fasteners, connectors, and brackets to corrode far faster than usual. This type of corrosion is called galvanic corrosion.

Galvanic Corrosion

Galvanic corrosion is an electrochemical process that occurs when dissimilar metals contact each other in environments containing moisture. One of the main ingredients used to create pressure-treated wood is copper. Galvanic corrosion occurs when copper compounds in wood meet the hardware used in outdoor construction.

Metals Most at Risk of Corrosion when Used with Pressure-Treated Wood

Some metals fail more quickly than others. Here’s a look at how various metals perform.

  • Plain carbon steel is very vulnerable to galvanic corrosion and will corrode quickly.
  • Electro-galvanized steel (thin zinc coating) is not suitable for use with treated lumber and will quickly corrode.
  • Hot-dipped galvanized steel (heavy zinc coating) is better, but only if it meets ASTM A153 or better standards.
  • Aluminum is highly reactive with copper compound and should be avoided.
  • Stainless steel is the best option when grades 304 and 316 are used.
  • Copper and brass fasteners are more compatible but are rarely used due to cost and strength concerns.

Preventing Galvonic Corrosion with Pressure-Treated Woods

  1. Use the right hardware, including nails, bolts, screws, connectors, and brackets.
  2. Create a barrier. Use a protective rust-stopping coating such as HinderRUST on your fasteners, and/or use a plastic or rubber barrier between the metal and wood.
  3. Pay attention to your design. Keep water from pooling around your structures and ensure plenty of airflow to help keep the metal and wood dry.
  4. Inspect regularly to check for rust, deterioration or wood damage.

HinderRUST

HinderRUST, manufactured by Fluoramics, is a moisture-displacing rust inhibitor that provides surface film management by creating a thin boundary film of anti-corrosion properties to serve as a barrier against air, salt, chemicals, and water.

HinderRUST is a rust stopper engineered with Tufoil Technology, a proprietary technology that is solvent-free, non-flammable, and won’t evaporate away. It acts as a lubricant and wetting agent that spreads HinderRUST across the treated surface, displacing water and enabling it to bond to the surface and protect it from corrosion.

HinderRUST stops corrosion on all metals, including equipment, hardware, firearms, galvanized steel, fixtures, autos, tools, machinery, stainless steel, dies, and molds.

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