soils (certain types of soil don’t compact well, whereas others can’t be depended upon to remain in place without extra support)
Ramping up — a checklist
Many structures, such as decks and large shade structures (like pergolas), must meet building-code requirements. Irrigation systems are subject to plumbing codes, and lighting and wiring projects are subject to electrical codes. Observe the following list of construction basics for outdoor projects, and bring in the professionals for some or all parts of the project that aren’t in your wheelhouse:
Investigate regulations. Contact your local building department to find out which regulations apply to your project and whether you need to obtain a permit. Although states or provinces have standardized building codes, municipalities often refine them even further.Your home may also be subject to the guidelines or rules enforced by a neighborhood or homeowners’ association, which may include a design-review process that usually requires submitting a measured drawing (scaled plan), not just a rough sketch.
Draw plans. Work out construction details on paper, not on the job, by making scale drawings (quarter-inch, or small-square metric, graph paper makes this task so much easier). Sometimes elevation drawings are helpful; these drawings show plans from the ground up to illustrate height relationships. Part 1 discusses what to draw.
Require adequate foundations. Structures must be supported on concrete footings, gravel beds, or similar foundations. Designs vary with local climate, soil, and slope conditions, but the basic requirement is to place the weight of a structure on solid ground (below the frost line — the depth to which the ground freezes during winter, which can be 4 feet, 1.2 m, or even deeper) or on a stable, well-drained bed. Also all rot-prone wood must be elevated at least 8 inches (20.3 cm) above grade (aboveground level).
Choose building materials carefully. Wood remains popular, but you have other options. See the section, “About Wood Alternatives,” later in this chapter.
Utilize corrosion-resistant fasteners and hardware. Use nails, screws, and hardware that are galvanized or otherwise treated for outdoor use. For galvanized nails, we recommend HDG (which means hot-dip galvanized). Use fasteners that grip, such as spiral-shank nails or galvanized deck screws, for better holding power. One secret to building long-lasting outdoor structures from wood is to nail, screw, strap, glue, and connect the heck out of ’em!
If you use wood, choose finishes that last. Preservatives (which protect wood from destructive organisms), sealers (which repel moisture), semitransparent stains (light-bodied stains that reveal grain pattern), solid stains (which mask the wood), and paints help wood structures last for years. Some products contain two or more finishes, such as stains that contain a sealer, preservative, and/or ultraviolet-ray blocker. The most effective finishes are those that penetrate the wood, such as water repellents, water-repellent preservatives, and semitransparent stains, and those that are designated specifically for outdoor wood structures, not just for general use.
Manage materials carefully. Estimating, ordering, obtaining, delivering, and storing materials is a major part of construction. Many materials are readily available from home centers, but you may have to locate a masonry yard, concrete supplier, fencing specialist, or similar outlet for others. Discuss delivery fees with suppliers.Plan your job so that you move materials only once by storing them near (6 to 10 feet, 1.8 to 3 m from) the construction site. Stack lumber on a flat, dry, shaded surface, such as a patio or garage floor, to keep it from warping. (Keep lumber off dirt or grass.) Create shelf space to store nails, bolts, screws, and similar hardware. Store bags of cement or mortar mix out of the weather. Use a wheelbarrow or arrange for a helper to move sand, gravel, and masonry materials from the street to your yard. Avoid storing materials and equipment under a tree (within a tree canopy area) because the resulting soil and root compaction can lead to tree death, if not right away, in a couple of years.
Have a plan for debris. Figure out ahead of time where to haul your debris in the likely event that regular trash services won’t pick it up. To make disposal easier, separate trash, clean fill, toxins, and reusable scraps. Arrange for a disposal service to haul everything away, if you can’t do so yourself.
Understanding wood and its alternatives
Lumber remains the most widely used construction material, certainly for decks and fences; however, lumber isn’t your only option. The following sections examine wood and lumber alternatives and help you make your choice of which to use based on your project’s size and needs, your taste, and your budget.
About wood
All wood is not created equal. Only certain grades (called heart grades) of certain species (cedar, redwood, cypress, and some tropical woods) are naturally resistant to decay. Many nondurable woods, such as pine and Douglas fir, aren’t decay resistant, but they are available as pressure-treated with preservatives and stains. They’re treated for either aboveground use or for ground contact.
Here are some general tips to bear in mind when looking at wood for your projects:
Consider strength. These requirements vary depending on whether you’re considering a deck (that needs to support furniture, perhaps a grill, and a number of people at times) or a structure such as a pergola, arch, or fence that will only support the growth of a vine. Southern pine, Douglas fir, and cypress are stronger than redwood, cedar, and other pines. Black locust is becoming more popular and larch, where available, may be suitable. In recent years, there has been a disheartening decline in lumber quality as tree plantations grow the wood too fast and/or harvest it too young, resulting in reduced strength and durability.
Inspect your potential purchases for flaws. Sight along a board looking for warping and twisting. Knots are okay if tight and in-grown, whereas loose ones are a bad sign.
Pay attention to size. The thickness and width of boards are expressed in nominal dimensions, such as 2x4 or 1x6, but the actual dimensions are less: ½- to ¾-inch (.5 to 1.9 cm) less (a 2x4, for example, is 1½ by 3½ inches, or 3.8 by 8.9 cm). For length, boards come in 2-foot (.6 m) increments from 6 to 20 feet (1.8 to 6.1 m).
Be selective with the type. Choose boards with a high percentage of heartwood (the darker, richer-colored wood) and dense growth rings (at least eight per inch/2.5 cm). In addition, remember the following:Some woods, such as the heartwood of cedar and redwood, resist decay naturally. These woods also tend not to warp as much as other species. Although cedar and redwood lack strength for major load-bearing members, such as deck joists, they work well for fences.Nondurable woods (southern pine and Douglas fir, for example) that have been pressure-treated with preservatives make good fence materials. Bear in mind that treated lumber fencing really shouldn’t be used adjacent to edible plants (or used to make raised beds for food gardening — see Chapter 10), because the chemicals do leach into the soil over time. You can improve the appearance of most wood by staining or painting it, so consider durability and strength first.
About wood alternatives
You can construct many hardscape projects from lumber alternatives, principally plastics and composites, which we discuss here:
Plastic materials such as PVC (polyvinyl chloride) vinyl and fiberglass reinforced plastics (FRP) are generally used for fencing, arbors, deck skirting, and lawn edging. Many styles and sizes are available; they’re strong and versatile and require no maintenance. Some plastic fence materials are sold as kits, making installation easy.
Composite decking boards (CDB) are made from recycled or reclaimed materials with polyethylene (HDPE