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Preliminary Planning
The location and design of your deck should be influenced by several factors:Decks originally gained popularity as a way of adding outdoor living space on hillside lots. However, many decks today are built on level ground where they offer firm, dry footing close to the home.
- *Anticipated use (private sunbathing, large parties, family relaxation, outdoor cooking)
- *Air currents (allow flow of gentle breezes, block out prevailing winds)
- *Existing structure (should be compatible)
- *Sunlight (desire sun or shade)
- *Privacy (screen certain areas, avoid street noise, landscaping)
- *View (emphasizes a good view, mask a poor one)
- *Safety (children or grandchildren, senior citizens)
- *Access to home (adjoin kitchen, living room or bedroom)
- *Terrain (elevated deck, ground level, split level)
- *Other personal needs and preferences
Decks can be built just inches high or elevated will above the ground. They may be freestanding or attached to the home or other building. They can even be built in a second-story above a garage, carport, or other roofed structure.
It's important; of course, to make certain the deck does not seal access to any utility or drainage lines. If you aren't sure of the location or depth of buried electric, telephone, gas, water or sewer lines, it's a good idea to ask your utilities.
Keep in mind how you intend to use your deck. Will it accommodate benches, lounge chairs, perhaps a table for outdoor dining? How many people will be using the deck at any given time? These are elements which must be considered in planning for proper size and design.
Once you have decided on the basic size, shape and location of your deck, check local building codes. You may find that there are restrictions as to height and size within your sub-division or community. A construction permit will probably be needed, but don't apply for one until you've finalized your planning.
Don't order any lumber or start work until you're sure that your plans meet local requirements. The information provided here should meet any local codes, but you will need to check to see if there are any particular requirements in your town.
Construction tips
Here are some additional suggestions that may help you in building your deck.
- Always nail a thinner member to a thicker member.
- Drive nails at a slight angle toward each other for greater holding power.
- When toenailing, stagger opposing nails so they pass each other.
- Nails and other hardware should be hot-dipped zinc-coated (galvanized) or equally well-protected material. Otherwise, weather may cause them to rust, leaving streaks on your deck.
- For maximum holding power, use ring- or spiral-shank nails. They can help reduce warping of lumber.
- To reduce splitting, when nailing close the the edge of a board, drill a pilot hole about three quarters the diameter of the nail. For dense or brittle wood, blunt the points by striking them carefully with a hammer. Blunt nails cut through; sharp ones pry apart.
- Place nails no close to the edge than about half the board thickness and no closer to the end than the thickness of the board. When nailing closer to the edge, pre-drill holes.
- Use 16d nails on nominal two-inch decking. Use two at each joint with 2 x 4's laid flat; use three for 2 x 6's laid flat.
- Mill ends may not be square. Resquare and trim the ends. Take this step into consideration when figuring lengths and finished deck size. IT is a good idea to leave all the deck boards slightly longer than the finished size and cut them all to the final dimension after they are all nailed down.
- With lag screws, use flat washer under head.
- Use washers under nut and head of machine bolts and just under nut of carriage bolts.
- Wear gloves to help avoid splinters.
- Tops of upright structurals and joist ends should be beveled to a 30 to 45 degree angle for drainage to minimize moisture (see fig. 18, page 11). While pressure-treated wood resists end rot, it remains subject to splitting, checking and chipping caused by moisture-induced swelling and subsequent shrinkage, therefore sealing the deck is a good idea to protect the surface.
- When staining wood, follow the manufacturers' instructions. Wood should be dry for best results.
- Remember, you are about to do finish work, not rough framing. The results will be visible for years to come. There is no substitute for good construction techniques and workmanship. (This is not intended to scare you, just remind you.)
DESIGN
Decks consist of six parts: footings, posts, beams, joists, decking and railing. In planning for these you have three basic considerations: function, structural stability, and appearance.The aesthetics of your deck will probably be most noticeable in your choice of railing and decking, but the location of posts and beams can have a major effect on the appearance of a raised deck.
In almost every instance, your choice lies between several small pieces of lumber or comparatively fewer large ones. A railing, for example, may be held by 2 x 4 posts spaced every 16 inches or less, or it may have 4 x 4 posts capped by a 2 x 6 spaced as far apart as eight feet. (Note: a 2 x 4 isn't always 2" x 4". Actual size of finished dry lumber is typically 1/2 inch smaller than the nominal size.
Your best guide at this stage is to look at various deck plans and inspect decks completed by friends and neighbors to help decide what you like best.
Choosing decking lumber presents similar alternatives. A popular choice is 2-inch thick lumber in widths of 4 or 6 inches. These can be alternated to make more interesting patterns. There is also 5/4 decking, which has rounded (bullnosed) edges to give the deck boards a more finished, softer look.
Develop your own design using the tables and information that follow. Clicking on the table reference will bring you to the table page. There will be an easy return link back to here on the table page. Take a look at the Tables 1 through 5. The figures given are for maximum spans using pressure-treated wood. Inferior grade wood will not safely span the distances in these tables. More on how to use the tables will follow below.
The design and construction information presented here is for normal usage. If special loading conditions are anticipated or unusual circumstances exist, consult a competent designer.
SUPPORTING A DECK
Elevated decks have generally been supported by 4x4 and 6x6 solid timber posts. Under a properly designed deck, these can provide very satisfactory support. Deck posts support the deck above, they are its foundation. The first consideration, then, should be the ability of a post to support the structure and the people on it.ACCESSORIES AND CONNECTORS
Some of the special connectors and accessories that you should be familiar with are:Make sure all connectors, nails, screws, bolts and related hardware are hot-dipped zinc-coated or otherwise rustproof. Remember, pressurized wood will remain in serviceable condition long after ordinary nails and connectors have been weakened by corrosion. Rust will also cause unsightly stains. The same conditions that cause untreated wood to rot also cause metal to rust.
- Lag screws
- Expansion bolt (for bolting into the cement foundation, if necessary)
- Carriage bolt
- spiral nails
- ring shank nails
- joist hangers
- post fasteners (to fasten a wooden post to a cement footer)
USE THESE TABLES TO HELP PLAN YOUR DECK
Let's say that your deck will extend eight feet from the house and be 14 ft. long. If it is to be just above ground level, there's little need for a railing. However, higher decks call for a sturdy railing.Table 1 shows the appropriate beam size. For example, the distance between the house and the beam is 8 ft. Using (2)2x12's as your beam members allows a span of 7 ft. between posts, a convenient figure for a deck 14 ft. long. A beam can be built up from two small pieces either nailed together or placed a few inches apart on either side of a post. Be sure you have a post under any joints in your beams.
To calculate the size post needed, multiply the beam spacing (eight ft.) by the post spacing (7 ft.). This gives you the load area-56 square feet. Table 2 shows that for a load area less than 72 sq. ft. and a post height under 6 ft, a 4 x 4 post is adequate.
Decking in this example will be a 2 x 6 boards, laid flat. Table 3 shows the safe spans for the decking.
Now refer to Table 4. As in our example, your joists must span the 8 ft. between the house and the outer beam. That can be achieved with 2 x 8 joists spaced 24 inches apart. To avoid any springiness in your deck, however, you should design with joists 16 inches apart.
If a railing is desired, refer to Table 5 to determine proper post sizes and spacing requirements. Be sure to check your local code here since the space between balusters is usually specified to be sure the small heads of children can not get stuck between them.
Estimating
After deciding the type, shape and size of deck you'll build, the next step is to estimate the materials you'll need. If you use a ready-made design, and the materials list is provided, this work is already done for you. But if you design your own deck, or use a variation from a standard plan, you'll have to estimate material requirements. In estimating, it's better to overestimate since you can always use any excess material in other projects, such as benches or planter boxes. There is nothing worse than running out of material and dashing off to the lumber yard before they close (hopefully) right in the middle of the project. (On the other hand, you may just looking for a break!)First, draw a simple sketch of the deck; decking, rails, footings, posts and beams. Sketch the deck to scale, perhaps ¼" per foot. To save money, stick to standard lumber sizes and lengths to the fullest extent possible. For example, deck boards are usually stocked 2 x 4, 2,x 6, or 5/4 x 6 inch and 8, 10, 12,14 and 16 foot lengths. I usually keep a sale flier from the lumber yard handy to be sure I know what sizes of lumber stock. For the decking, calculate using actual dimensions (5 ½ for a 6 in boards) and don't allow for spacing between boards. (More on that later, but I recommend little or no gap between the boards).
We present the second part of this article with step by step instructions in How To Build A Deck Part 2.
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