Shop Treated Decking

Arlington Coal and Lumber Company is your trusted source for top-quality treated decking and lumber. We provide accurate material take-offs and reliable job site delivery for professional contractors, custom builders, and DIYers throughout Greater Boston, Massachusetts, New Hampshire, and the surrounding New England region. Visit our regional locations: Arlington Coal and Lumber Company, Burlington Lumber Company, Wilmington Builders Supply, Sudbury Lumber Company, Chelmsford Lumber Company, and Hudson Lumber Company.

Why choose treated decking from Arlcoal.com? Treated decking products, often called pressure-treated wood, start as milled softwood (typically Southern Yellow Pine due to its superior cellular structure for chemical absorption). The wood is placed in a pressurized cylinder where a vacuum removes air and moisture, forcing a liquid preservative deep into the wood. This creates a highly durable material resistant to fungal decay, wet rot, and wood-boring insects.

The most common and effective modern treatments are copper-based, including:

• Micronized Copper Azole (MCA): Uses finely ground copper particles suspended in water, resulting in a lighter color and significantly less metal corrosion on fasteners.
  
  
• Alkaline Copper Quaternary (ACQ): A water-based preservative offering robust protection against decay fungi and insects.
  
  
• Copper Azole (CA-C): Features organic fungicides, frequently specified for residential decking and above-ground trim.
  
  

These treatments create a powerful biocidal barrier, extending the wood's usable lifespan in challenging outdoor environments. Treated lumber lasts significantly longer than untreated wood in exterior applications, providing a structurally sound solution. It machines cleanly with standard woodworking tools and accepts exterior stains and paints well once the wood has dried sufficiently after installation.

Ideal applications for treated decking and framing:

• Decking substructure: Treated lumber is mandatory for the structural framework of a deck, including posts, beams, joists, and stair stringers. Using treated wood ensures the foundation remains sound for decades, even if composite decking is used for the surface.
  
  
• Ground-contact applications: Critical for any wood in direct contact with soil or fresh water, requiring a higher chemical retention level (AWPA UC4A or higher). This applies to fence posts and support posts resting on concrete footings.
  
  
• Fences: Essential for buried fence posts and bottom rails close to damp ground, preventing premature failure at the base.
  
  
• Retaining walls: Specified for structural wood retaining walls, as the lumber is constantly exposed to heavy soil moisture.
  
  
• Outdoor structures: Excellent for framing gazebos, pergolas, sheds, picnic tables, and outdoor playsets where weather durability is paramount.
  
  
• Raised garden beds: Modern copper-based treatments are safe for building raised vegetable garden beds, providing structural borders that resist rot.
  
  

Professional installation tip: The copper content in modern pressure-treated wood will rapidly corrode standard steel. You must use structural fasteners and joist hangers that are hot-dip galvanized (meeting ASTM A153) or made from Type 304 or 316 stainless steel. Additionally, apply a brush-on copper naphthenate wood preservative to any cut end-grains to maintain the chemical envelope and prevent moisture wicking.

Start your next exterior project right with the local experts at Arlington Coal and Lumber Co. We maintain a massive inventory of various grades and dimensions perfect for everything from structural deck framing to essential landscaping timbers. We supply the exact materials required to meet building codes. Explore our wide selection of top-quality pressure treated products, including dimensional lumber, treated framing, treated posts, plywood and lattice, treated plywood, and stringers and balusters (balusters and stringers).