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Preparing for the Project

The transition from theory to practice can be the most difficult phase of a deck-building project. This is the point where doubts may start to plague you.

■ Will the deck be big enough?

■ Can I really afford to build it?

■ Do I have the skills needed to build a deck?

Listen carefully to the doubts and try to answer them thoroughly before proceeding. Don’t rush into the project. Think through all of the procedures and consequences. If you’ve recently moved into the house, it might be too soon to build a deck. By waiting a full year, you’ll have time to observe the house and yard through a full course of seasonal changes and weather conditions.

Budgeting is a tricky—and highly personal—part of the project. With thorough planning, however, you can avoid surprises. As long as you supply all of the labor, you can determine your out-of-pocket expenses by preparing a detailed list of materials (drawn from your equally detailed plans), which you can take to several suppliers for estimates. If your budget is tight, only you can decide if you want to borrow the money and build today or save your money and build tomorrow.

Deck building is straightforward work, but parts of it are physically demanding. And all of it requires close attention to detail. If you remain concerned about your ability to build the deck you want, narrow down those parts of the job that trouble you the most. Perhaps you worry about getting the ledger installed correctly or the posts set plumb and in a straight line. If so, take on the role of general contractor and subcontract parts of the job. You may be able to hire an experienced carpenter to do those segments of the job that you feel uncomfortable about. This mini-apprenticeship may be all you need to boost your confidence for tackling your next remodeling project. No matter how long it takes, resolve your doubts before ordering lumber. Once that delivery truck backs into your driveway, you want to have a building permit in hand, a clear idea of what your deck will look like, and a plan for who’s going to handle the work.

Caution - Whose Property Is It? Properly owners often are surprised to learn about the many restrictions placed upon their building projects. Just because you know where your property lines are and plan to stay within them, don't assume you've covered all the bases. You may be required to observe setback stipulations. Some locales insist that you keep all parts of a new deck a specified number of feet away from adjoining property lines. You may even have to have your lot surveyed to verify property lines. Historic districts and subdivisions may limit the size or style of the deck you can build. You may be able to challenge the restrictions by requesting a variance, but the time to do that is before you build, not after you've started the project.

Keep it legal. Like most major home improvements, a deck addition must be done in compliance with local building codes and zoning laws. Submit plans to your town or county building department for approval and to obtain a building permit. Depending on its policies, the building department also may require inspections to make sure you’re following the approved plans. This legal supervision ensures that your design will be built properly. Remember, building codes prevent your neighbors from doing things you might not like. Failing to comply with codes could result in having to remove what you’ve built. Not everyone is covered by zoning laws or required to get a building permit. But it’s up to you, not the authorities, to find out what laws cover your project.

Play it safe. The elements that make decks useful, fun, and good-looking, such as stairways, railings, multiple levels, hot tubs, or high elevations, also create safety hazards, especially for children. Complying with local building codes doesn’t guarantee a safe deck. Legal requirements represent minimum standards; your situation may demand more. Minimize risks by observing these precautions:

■ When building a deck railing, space the balusters no more than 4 inches apart, even if your local code allows wider spacing.

■ Treat deck stairs the same as indoor stairs; if young children are around, put a gate at the top and bottom.

■ If you install built-in benches, make the railings behind them at least 24 inches above the seat to prevent a child from climbing or tipping over the side.

■ Hot tubs should be fenced off with a childproof gate. If that’s not practical, use a secured cover.

Make a trial run. Mark the perimeter of your deck and its various levels with flour. Place your lawn furniture inside the perimeter to get a feel for how much space you need. Use strings to indicate railing heights. Set the string lines at the height of the proposed deck to give you a sense of its profile.

Take a Shortcut

■ You may be surprised at the time- and money-saving services available at your local home center or lumberyard. They may offer ready-made plans, either sold individually or collected in book form. If you find a plan you like and your building site presents no unusual problems, the cost of printed plans can be money well spent.

■ If you want a simple deck that’s neither large nor fitted with many custom features, consider buying a precut deck kit. Some larger home centers and lumberyards offer these complete deck packages at attractive prices.

Calculating Spans

Posts, beams, joists, and decking comprise the structural members of a deck. Their spacing and sizing are critical to ensuring a deck is safe and secure. Building codes vary, and it is up to you to contact your local building department for guidance in designing your deck. When calculating allowable spans, be aware that specifications vary depending on the type of wood you use. Also, spans often change for a deck that is higher than 12 feet. And when you change the size or spacing of one structural member, it can affect the size and spacing of others. For example, you could use fewer posts, spaced farther apart, if you use a larger beam.

The table at right lists spans typically allowed for pressure-treated (pt) Southern yellow pine. The calculations that produce these spans assume that the deck must support a load of 50 pounds per square foot. That figure breaks down into 10 pounds per square foot of “dead weight” (the weight of the construction materials) and 40 pounds per square foot of “live weight” (the weight of people and objects on the deck).

Wood Strength Varies - Species and grades of wood vary in strength. Design your framing with the strength of the wood in mind. Southern yellow pine and Douglas fir have the same allowable spans and are the most common types of pressure-treated framing lumber. Redwood and Western red cedar are weaker and so need shorter spans. Check with your local lumberyard or home center for the types of lumber available and suitable for use in your area.

Choosing Hardware

Using the right fasteners is important. This is no place to save a few dollars. Fasteners and connectors must withstand years of exposure without rusting or otherwise weakening their grip. Every fastener should be suitable for long-term exterior use. Galvanizing is the most common treatment for metal fasteners used outdoors. But there are differences in the methods and materials used in galvanizing. The best process is hot-dip galvanizing, in which the fastener is dipped in molten zinc. The thickest coating of zinc is found on fasteners that meet that standard—ASTM A153. Stainless steel fasteners cost considerably more, but they are extremely resistant to degradation. Use them near saltwater or other regularly wet or corrosive conditions. Aluminum fasteners are not recommended.

Use galvanized nails. When nailing on the decking boards, ring- or spiral-shank nails provide a much better grip than common wood nails. On the other hand, they can be difficult to remove if you need to replace decking. Hot-dipped galvanized nails are best for most decks. Use stainless steel for extremely wet or corrosive applications.

Screws hold well. Stainless steel, anodized, or hot-dipped galvanized screws are excellent choices for fastening decking. Screws for this purpose often are referred to as decking screws. They are available in 2- to 3-inch lengths, with either Phillips or square-drive heads. Do not use regular black-coated screws intended for wallboard or other interior purposes.

Use bolts and masonry connectors for strong joints. The strongest fasteners for joining structural members are machine and carriage bolts. Machine bolts require a washer on both ends; carriage bolts require a washer only on the nut end. Carriage bolts have a rounded head. Use 1/2-inch bolts unless directed otherwise. Lag screws are necessary when access is restricted. Use anchors when fastening ledger boards to masonry or concrete foundations.

Post and joist connectors simplify joint work. Ready-made lumber connectors have simplified many aspects of deck construction. Seismic (or hurricane) anchors help secure joists to beams. Post anchors tie posts to the concrete piers via a J-bolt, eliminating the need to embed posts in concrete. Joist hangers offer a secure pocket for joists, while post caps allow a quick means of supporting beams on posts.

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