Designing Decks with Wood
Although decks share common building materials, differences in color, texture, and harmony make a design distinctive. Color can link the deck with your home and help set the mood. Earth tones generally appear warm and complement traditional settings. Blues, grays, or blacks appear cool and enhance contemporary designs.
Texture also affects the appearance of a deck. Both decking patterns and baluster styles establish a visual texture that can make your design a harmonious addition to your landscape.
Selecting lumber Sizes
To build a deck that is visually appealing and structurally sound, you need lumber in sizes that fit the scale, strength, and span requirement of your design.
Compared to the work of framing your deck, installing decking boards will seem easy. But don’t take this part of the project for granted. The surface must endure more weather and wear than any other part of the deck, and it will be the first thing anyone notices about your work. Choose materials and sizes that complement your design.
Determine joist spans: Using the same procedures, compute the maximum joist spans. Running the numbers again shows you that your 2×10 western pine joists spaced 16 inches (or less) on center will span beams that are set 13 feet apart—more than enough for your 10-foot deck.
If your previous computations had resulted in a joist spacing of 32 inches, you could span only an 8V2-foot space between the beams. In this instance, you could still use the lumber of your choice, but you would need a third beam.
Calculate post spacing: Now you need to figure out how far your beams can span—that is, how far apart you should place the posts. In general, you want your beams to be large enough to keep the number of posts to a minimum, but not so large that they are out of proportion with the rest of the design.
Let’s say you like the looks of 6-foot post spacing. Look down the 10-foot column (that’s how far your beams are spaced from your previous computations) in the “Beam Spans” table, opposite, until you find the 6-foot spacing for western pine.The table indicates that you’ll need a 4×10 beam for posts spaced every 6 feet. If you change your mind and want posts spaced every 8 feet, you’ll have to use a 4×12 beam. The trick is to balance beam size with the number of posts. Too many posts results in undue complexity, difficulty, and expense. Too few posts results in a risk of instability.
compute post size: Multiply the spacing between beams (10 feet, in our example) by the spacing between posts (6 feet in our example) to compute the load area in square feet (60 square feet in our example), find this number in the “Sizing Posts” table, opposite, and follow the column down to “Western pine.”
Remember the deck railing
You’ll perform the most complicated computations when you figure out the sizes of various structural members. Choosing railing stock is less frustrating and pretty much follows standard sizes.
Use 2x stock for rails and 2x2s for balusters, unless your design calls for special stock. Whenever possible, purchase rail and cap pieces long enough to avoid splicing.
No lumber is perfect, so to get the materials that are right for your deck, take an exploratory trip through your lumberyard. Look at the different species and examine their color and grain patterns. Assess quality differences among the grades.
Compare pressure-treated with untreated products. If you don’t have a good idea of what you’d like to use, take your scaled plans with you and ask a salesperson to give you recommendations and an idea of costs. Then take a second look. Keep in mind that stains and sealers will make the finished wood look darker. There’s no general guideline that can help you estimate the exact effect of finishes. Each product “takes” differently on each species. To get a rough idea of how your deck will look when finished, look for samples displayed with the finishing products. The samples will represent the approximate outcome of the finish on your wood.
Go through the lumber racks, pick up each board, and check for defects. Sight down the length of boards on both the flat side and the edge. Are they crooked? Warped? Or square and flat? Check for knots. Are they small and tight? Or loose and large? Look for checks and splits. If the wood hasn’t been kiln-dried, you can expect more checks and splits to develop as the lumber seasons.
Take time to inspect every board before you buy it, and be careful how many imperfections you accept. Flaws in decking boards or the stock you’ll use for railings will detract from the appearance of the deck and may cause premature wear. Some defects in framing lumber won’t affect the strength of the structure. Others can be structurally dangerous and may be hidden once you install them.
Some defects—such as knots, shakes, checks, or splits—are natural (that doesn’t make an abundance of them acceptable, however). Others, such as torn grain or warping, are the result of milling errors or poor drying conditions.
If you’re planning a simple project, the best way to estimate your lumber needs is to use your dimension plan and count all the pieces of each size. That way you can give your supplier a list of the exact number of 2x4s, 2x6s, and so forth. Keep your costs down by keeping the waste to a minimum. Most lumber comes in even lengths, so if you need a 3-foot and a 6/^2-foot 2×10, you’ll need to order a 10-foot board from which to cut them.
Ordering lumber requires attention to detail. You’ll need a list of each size stock, the species, what kind of footings (if any) you’ll be pouring, and how you will finish the structure. You may be able to negotiate a better price for materials if you place the full order with one supplier. When you’ve sorted everything out and have a good idea of what material you need, shop around to compare both material costs and service. You can quickly get an idea of costs by visiting your lumberyard and asking the salesperson to give you the materials cost for a basic deck of your size. Ask for estimates from several suppliers.
You might find that a higher-grade stock costs less at one yard than lower-grade materials at another. If you can’t get the material to the site yourself, factor in delivery costs before ordering.
Waste not, want not
This is an adage that does not apply to construction work. You’ll waste a certain amount—it’s unavoidable. Order 5 percent more than your materials list calls for.
Avoid scrimping on the quality and quantity of fasteners in your project. After all, it’s the fasteners that hold all your hard work together. Framing fasteners come in a variety of forms—nails, screws, lag screws, bolts, and metal framing connectors. You may need one or more masonry fasteners, too, if you build your deck on a slab or otherwise attach it to a concrete surface.
Nails hold things together by the friction they generate against wood fibers. The size of a nail is determined by its length expressed as pennyweight, abbreviated as d (which stands for denarius, an ancient coin; it referred to the cost of 100 nails of a given size).
- COMMON NAILS, used for general construction, have large heads and thick shanks. They hold well but are hard to drive and may split the wood.
- BOX NAILS, thinner than their common cousins, reduce splitting in stock that measures /Vinch or thinner.
- RlNGSHANK AND SPIRAL-SHANKED NAILS grip the wood fibers better than common or box nails and don’t easily work their way out. They are very difficult to remove.
- FINISHING NAILS have slender shanks and small, barrel-shaped heads that can be countersunk. Use them for trim work and wherever you don’t want the heads to show.
- CASING NAILS are heftier versions of finishing nails with more holding power.
- BRADS are miniature finishing nails used for attaching thin, fragile pieces.
Nails or Screws?
For most projects, nails will prove the least expensive fastener. Screws cost more, but they create a stronger joint, and ultimately that can mean a longer-lasting structure. And even though driving an individual screw may take slightly longer than pounding nails, screws can save you time in the long run. An air or power nailer makes nailing go extremely fast and can be well worth the cost of the rental fee. You may want to practice on scrap before engaging this tool in construction.
Once a board is split by a nail or screw, not only is the board unsightly, the fastener has lost almost all its holding power. Small splits will almost certainly grow in time. Save time and disappointment by drilling pilot holes wherever there is a possibility of splitting—especially close to the end of a board.
Drill a pilot hole using a drill bit slightly smaller than the nail. Test by drilling a hole and driving the nail. It should be snug enough so it takes some hammering to drive it in.
Try this trick for attaching softwood trim: Insert the finishing nail in the chuck of your drill. Drive the nail with the drill until it contacts the framing. Finish driving the nail with a hammer.
Many types of combination heads will not hold a phillips tip securely against the torque of a cordless drill, especially when fastening 2x framing. If you’re stripping your combination-head screws when you go to sink them, switch to a square tip.
The metal used to fabricate a nail makes a difference. Some nails rust readily; others won’t ever rust.
- GALVANIZED NAILS are the most common type. Hot-dipped galvanized (HDG) nails are more reliable than electrogalvanized (EG). They resist rust, but no galvanized nail can guarantee rust-free performance. The coating often flakes off.
- ALUMINUM NAILS won’t rust, although they aren’t quite as strong as HDG nails and can be very difficult to drive (they bend), especially in hard woods.
- STAINLESS STEEL NAILS won’t rust, but they are very expensive, and not all suppliers stock them. They’re a good choice and worth their expense for projects built near salt water.
Nails and screws are the mainstay fasteners, but bigger connections call for heavy-duty hardware:
BOLTS: Bolts, nuts, and washers provide a solid connection with excellent load-bearing strength. They hold parts together by compressing their surfaces, and their size is designated by their shank diameter (under the head) and their length. Use only those with a hot-dipped galvanized finish, and predrill them with a drill bit of the same diameter.
- MACHINE BOLTS have a hex or square head.
- CARRIAGE BOLTS have a rounded head for a decorative or finished appearance.
What Size Fastener? –
The longer and thicker a nail, the better it holds. However, if a nail is too thick for the stock, it will split the wood and have almost no holding power at all.
Although it might seem that building a deck calls for a wide selection of fasteners, those listed below will get you through most projects.
- Common, spiral, or ringshank nails (lOd or 16d) for framing—in 2x or thicker stock
- Box or ringshank nails (8d or lOd) in lx or thinner stock
- Finish nails (8d or lOd) for trim
- Decking screws (#10, in appropriate lengths)
Tighten machine screws with two wrenches (putting washers under the head and nut). Carriage bolts have a square shank under the head that pulls into the wood and keeps the bolt from turning. Tighten both fasteners until they are just snug and make the slightest indentation in the surface of the wood.
LAG SCREWS: A lag screw is a bolt in a screw’s clothing. Its large size will attach heavy framing members and hardware. Lag screws have a hexhead (square heads are available but uncommon). Tighten them with a wrench.
MASONRY FASTENERS: Masonry fasteners are similar to nails or screws. Some are made of hardened steel; others rely on expansion and friction to grip the masonry.
FRAMING CONNECTORS: Framing connectors are designed for a number of special purposes.
Most manufacturers supply nails (usually blunted to reduce splitting) for framing connectors, but you can use common nails of the closest size, cinching the nail if it’s longer than the framing.
Get a Grip
Whether you assemble your deck with nails or screws, make sure that two-thirds of the fastener shank is in the lower (usually the thicker) member of the joint. Where possible, and to get the best holding power, drive the fasteners at an angle, toward or away from each other.
If it weren’t for the weather, you wouldn’t have to worry much about the durability of your deck. But wind, rain, snow, ice, and sun exact a heavy toll on wood. The right finish can help protect your deck and enhance its look.
There are many ways you can finish your deck, depending on the type of lumber, your preference of color, and the deck’s environment. Here are some guidelines you can use in selecting a finish and applying it.