Backyard deck planning involves more than picking a spot and choosing boards. A safe, long-lasting deck starts with understanding the structural rules, selecting the right wood, and committing to regular upkeep. Whether you are building new or refreshing an older deck, a few key steps can help you avoid common pitfalls.

Short version: Focus on DCA 6 guidelines, call 811 before digging, use treated or naturally durable wood, apply penetrating finishes, and keep wood away from soil.

What DCA 6 Covers and Why It Matters

The American Wood Council’s Prescriptive Residential Wood Deck Construction Guide, commonly called DCA 6, is a widely referenced document for single-level residential wood decks. According to the AWC, DCA 6 provides prescriptive construction methods based on the 2015 International Residential Code (IRC). It is not a universal building code; a local jurisdiction may adopt it, modify it, or require different standards. The guide states that all construction and materials must be approved by the authority having jurisdiction. So before you begin, check with your local building department to learn which rules apply in your area. Permits and inspections are handled locally, and requirements vary.

DCA 6 addresses several structural details: ledger board attachment to the house, footing design, guard and handrail requirements, and stair construction. It also sets minimum post sizes (6×6 nominal) and specifies corrosion-resistant fasteners and connectors. However, the guide explicitly excludes decks supporting large concentrated loads such as hot tubs, and decks in areas with snow loads exceeding 40 psf. For any load-bearing work beyond these prescriptive limits, the AWC recommends that alternative designs be approved by the local authority. If you are not experienced with structural framing, consider hiring a qualified builder or deck inspector to review your plans.

Before You Dig: Contact 811

Any backyard deck that requires footings, posts, or trenches means digging. The national before-you-dig service, 811, reminds homeowners that even shallow projects can hit buried utilities. According to 811, you should contact the service or visit your state 811 center’s website a few business days before you start digging. You will need the project address, county, nearest cross street, and the exact digging area. After you contact 811, wait for utilities to mark their lines with paint or flags, and dig carefully around those marks. The 811 service notes that not calling before digging is the top cause of utility damage each year, and even hand tools like shovels can strike lines buried just inches below the surface.

Choosing the Right Lumber

Deck lumber must resist decay and insects. The American Wood Council’s DCA 6 requires that all lumber be either a naturally durable species (such as redwood or western cedars where 90 percent or more of the width of each side is heartwood) or preservatively treated according to American Wood Protection Association standards. Lumber in contact with the ground must be approved for ground contact. The USDA Forest Products Laboratory’s Wood Handbook notes that wood species vary in how well they hold finishes; lower-density woods with narrow latewood bands, like western redcedar and white pine, tend to provide better finish performance than high-density species with wide latewood bands.

When selecting treated wood, it is important to know that chromated copper arsenate (CCA) treated wood is no longer manufactured for residential uses. The U.S. Environmental Protection Agency states that CCA manufacturers voluntarily discontinued residential uses in December 2003. If you have an older CCA-treated deck, the EPA suggests applying a penetrating protective coating regularly to help reduce leaching of chemicals. For new construction, choose wood treated with other EPA-approved preservatives or naturally durable heartwood species.

Finishes That Protect and Last

The finish you apply to a deck does more than add color; it shields the wood from moisture, sunlight, and mildew. The USDA Forest Products Laboratory’s guide on finishes for wood decks strongly recommends penetrating finishes over film-forming ones. Penetrating finishes include water-repellent preservatives (WRPs), colored WRPs, and semitransparent stains. According to the FPL, film-forming finishes like paints and solid-color stains tend to trap moisture and peel, especially on horizontal walking surfaces. A WRP finish may last about one year on exposed surfaces, but it is easy to reapply and soaks into end grain well. Colored WRPs and semitransparent stains, which contain more pigment, can extend the service life significantly.

The Wood Handbook adds that semitransparent oil-based stains penetrate without forming a continuous film, so they resist blistering and peeling. If you are unsure which finish to use, the FPL suggests starting with a WRP; you can switch to a semitransparent stain later. Before applying a new finish, clean the deck with a deck cleaner or brightener to remove mildew and dirt. The FPL cautions against aggressive power washing, which can erode soft wood fibers, and advises allowing the deck to dry for at least two warm, windy days after cleaning. For railings, where abrasion is less of a concern, paints and solid-color stains may perform adequately if the design avoids trapping moisture.

Keeping Termites at Bay

Subterranean termites are a serious threat to wood decks, especially where wood contacts soil. The University of Missouri Extension explains that subterranean termites live in the soil and build shelter tubes to reach above-ground wood. They enter structures through cracks as small as 1/32 inch, gaps around plumbing, or direct wood-soil contact. To reduce the risk, the Extension recommends several practices: remove all wood debris from the soil before backfilling, maintain at least 4 to 6 inches between the soil surface and the bottom edge of siding or other wall coverings, and never allow wood to extend into or through concrete to the soil. Use treated lumber for sill plates and other components near the ground. The Extension also notes that termite damage progresses slowly, so if you find signs of infestation, you have time to select a qualified pest management professional. Regular inspections of wood near the foundation can catch problems early.

Putting the Plan Together

A thoughtful deck plan ties these elements together. Start by sketching the deck’s location and dimensions, keeping in mind that DCA 6 applies to single-level decks where the overall length is equal to or less than the overall width. Check with your local building department about permits, inspections, and any local amendments to the IRC. Call 811 a few business days before digging footings. Choose lumber that meets the DCA 6 requirements for decay resistance, and avoid CCA-treated wood for new builds. Plan your finish: a penetrating stain or WRP will be easier to maintain than a film-forming coating. Design the deck to keep wood away from soil, and include a termite inspection strategy. If the project involves complex framing or heavy loads, consult a qualified builder or structural engineer. For more ideas on integrating a deck into your overall backyard layout, see our backyard design resources. And if you are also considering a ground-level hardscape, read How to Plan a Backyard Patio: Size, Site and Surface. For more on structural options, browse our backyard structures section, and for upkeep advice, see our backyard maintenance tips.

Frequently asked questions

Do I need a permit for a backyard deck?

Permit requirements vary by city, county, and state. The American Wood Council’s DCA 6 guide is a prescriptive standard, but local building departments decide whether to adopt it and what permits are necessary. Always contact your local building department before starting construction.

Can I build a deck directly on the ground?

No. DCA 6 requires that all lumber in contact with the ground be preservative-treated wood suitable for ground contact. Even then, the University of Missouri Extension advises avoiding wood-soil contact to reduce termite risk. Decks are elevated structures; a ground-level platform would be a different type of project, such as a patio. For patio planning, see our patio guide.

How often should I refinish my deck?

The USDA Forest Products Laboratory states that a water-repellent preservative finish may last about one year on exposed surfaces, while pigmented penetrating stains can last longer. The exact interval depends on sun exposure, foot traffic, and climate. Inspect the deck each year and refinish when the old finish has worn thin, which is the point the Wood Handbook uses for exterior wood.

For more detailed guidance on deck materials, construction, and maintenance, visit our Decks category page.

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