The right material can make all the difference in creating beautiful, long-lasting wood decks in Arlington, VA.
When it comes to durability and wood decking materials: water, insects, and weather are the great villains. Naturally, there are three heroes: wood that is pressurized or chemically treated to resist rot, wood that is naturally resistant to rot, and synthetic wood materials.
Lumber is divided into grades based on flaws like knots and splits. The straightest, most pristine boards are reserved for visible deck surfaces. We recommend using the highest grade lumber you can afford, especially where structural integrity is concerned. You can save money buying mid-grade lumber for structural underpinnings of a deck, but avoid the lower grades. Knotty, warped lumber is challenging to work with and can weaken the deck framework critical for load bearing support.
What to look for:
Pressure-treated lumber – The least expensive and most popular deck material is pressure-treated (PT) lumber. Made of yellow pine or fir treated with preservatives to resist water. Look for kiln-dried or kiln-dried after treatment, in green or brown. PT lumber needs to weather for 90 days before it is stained or painted.
Rot-resistant wood – Cedar, cypress, and redwood naturally resist rot and are structurally strong. The exterior surfaces are soft and susceptible to denting and marking. They require careful handling. These wood deck materials are more expensive than PT lumber. You can reduce costs utilizing more expensive wood for components such as railings, built-ins, and surface decking, and using PT lumber for structural framework
Synthetic materials – Synthetic wood materials are your choice for low maintenance. Plastic lumber, manufactured of recycled consumer plastics, is impervious to moisture. Molded in a rainbow of colors, plastic lumber can also be painted. It mimics but does not replicate natural wood. Vinyl lumber, in white and several other colors, is similar to plastic lumber. Look for UV inhibitors injected directly into the vinyl rather than sprayed on post- manufacture. Wood-polymer lumbers are another synthetic wood option. They contain a 50 – 50 ratio of waste wood and recycled plastics that can be stained or painted. These products look and feel like wood but require limited maintenance.
Strength. Real wood is the only deck material approved for structural support use, PT lumber being the strongest. Plastic lumber, vinyl lumber, and wood-plastic composites are not strong enough or too flexible to bear weight
Maintenance. All wood requires regular refinishing to preserve and prolong its durable life. Check annually for loosening nails, splinters, or warped boards. Synthetic materials offer the lowest maintenance with just occasional washing
Decay-Resistant Wood Species for Decks & Porches
As described in Best Practices Guide to Residential Construction, Chapter Four, Best Construction Guide for Building Decks and Porches:
For a price, redwood and cedar are available in structural grades. How rot-resistant the untreated wood is depends on the amount of extractives in the wood, which is greatest in the heartwood cut from dense, old-growth trees. To purchase all-heart, structural-grade redwood or cedar, expect to spend two to three times more than for pressure treated lumber. It is also difficult to find away from the West Coast. Left untreated, even the heartwood of these species is not recommended for ground contact.
Horizontal deck surfaces take a beating. Rain and snow, exacerbated by wet-dry and freeze-thaw cycles, open up widening cracks, and ultraviolet radiation breaks down wood surfaces. The more sun exposure and water a deck sees, the quicker it will deteriorate. In addition, foot traffic makes it hard to maintain protective finishes.
When choosing a decking material, look beyond its short lived original condition to its appearance and maintenance needs down the road. In all cases, use the best grade of material you can afford. With wood decking, select tight, straight grain, few if any knots, and low moisture content.
The most decay-resistant materials are cut from the dense heartwood of old-growth trees, which is expensive and increasingly rare. In redwood, the lighter colored sapwood offers moderate resistance to decay.
Redwood and cedar should, at a minimum, be treated regularly with water repellants. Occasional treatment with a water-repellant preservative will increase the service life.
Tropical hardwoods are typically knot-free with a tight grain pattern that helps keep out water. They are strong, dense, and highly resistant to decay and insects, making them ideal for deck surfaces.