How to Build a Basic Deck

terrace deck construction - man installing wpc composite decking boards
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Overview
  • Working Time: 5 days - 1 wk
  • Total Time: 1 wk, 3 days - 2 wks
  • Skill Level: Advanced
  • Estimated Cost: $2,000 to $5,000

Building a deck creates a fun, comfortable space for family and friends to socialize, enjoy al fresco dining or barbecues, or just savor a moment with a cup of coffee. A deck is also a solid asset to any property and provides substantial resale value.

Building a basic deck doesn't need to be hard when you break it down into smaller sub-projects. Working through the process slowly and understanding everything that you're doing helps you build the deck safely, with no room for error.

Stages of Building a Basic Deck

  1. A basic square or rectangular deck attaches to the side of the house. To ensure a strong attachment, one side of the deck is attached to the house's structural members with a ledger board.
  2. The opposite side of the deck is supported by a heavy beam. The beam is parallel to the house and rests on vertical posts. The posts are supported by concrete footings sunk into the ground.
  3. The ledger board forms one side of the deck's four-sided outer framework. The other three sides are formed by one header joist parallel to the house and two outer rim joists perpendicular to the house.
  4. Within this framework are wood floor joists running perpendicular to the house.
  5. Deck floorboards are attached to the top of the joists.
  6. A staircase allows access to the deck from outside of the house.
  7. Installing a railing provides safety to the deck. Elevated decks with stairs need handrails around the deck perimeter and along the stairs.

What Is a Ledger Board?

Integral to building an attached deck, a ledger board (or ledger) is a horizontal piece of lumber that attaches to the side of the house. Bolts run through the ledger and into the studs of the house. Once the ledger is installed, joists can be attached at any point on the ledger.

Codes and Permits

In most areas, you will need to apply for a permit for an attached, elevated deck at the local permitting office. One advantage of building a detached ground-level or floating deck is that it often does not require a permit, as long as it remains below a certain height, often 30 inches.

By contrast, this project's deck is attached to the house, a condition that usually triggers permitting. Also, because the deck can be built higher, rails and balusters are required.

When to Build a Deck

Early autumn is prime season for building a deck, especially when you hire professionals to do it. Job orders tend to taper off for builders around that time. The ground is easy to work with as it isn't frozen. Temperatures are cooler and it's still dry, in most areas. Completing the deck in autumn means that it will be ready for use next spring.

As a do-it-yourselfer, though, building the deck in autumn may create pressure to finish before winter sets in. So, if you don't mind losing a couple of weeks of deck usage, starting the deck build in late spring will mean longer workdays and drier, warmer weather.

Before You Begin

The deck should be accessible from the house, through a back or side door. Never place a deck flush with the height of the flooring in the house. Instead, drop the deck by at least 3 inches.

The deck site should be level and clear of large obstructions in the ground, such as tree roots. Clear the site to the intended size of the deck, plus another 6 to 8 feet of buffer room for working.

Cost of Building a Deck

Building a small attached deck by yourself with pressure-treated wood floorboards will cost $2,000 to $5,000, depending on the size of the deck.

A professionally built deck of 300 square feet, with two benches, stairs, and a railing will cost more than $14,000 on average across the United States.

The choice of deck floorboards is a major factor in the overall cost of the deck. Pressure-treated wood flooring costs $2.50 to $4.00 per square foot. Wood composite decking is up to four times more expensive: $9 to $15 per square foot. At the top end of the price scale for decking are tropical hardwood species such as ipe, at between $17 and $20 per square foot.

Deck Floorboard Materials

  • Pressure-Treated Wood: Pressure-treated lumber is cheap, easily obtainable, and highly weather- and insect resistant. It's used as flooring on a majority of decks. The downside is that it's not very barefoot-friendly, since it produces splinters. Over time, too, pressure-treated wood will begin to crack and warp.
  • Composite Wood: Made of recycled as well as new plastic, plus wood fibers, composite wood decking never needs staining or coating. It doesn't split, rot, warp, or splinter. But composite wood decking doesn't span well, so you'll need to decrease the joist spacing.
  • Cedar: Cedar is about twice as expensive as pressure-treated wood, but it weathers well due to its inherent oils and tannins. Cedar generally resists insects. Stain takes well to cedar. But, like pressure-treated wood, it has a tendency to split and splinter.
  • Tropical Hardwoods: Tropical, imported hardwoods such as ipe represent the top end of decking materials. Their hardness and density mean that they don't take stains well, but they can be oiled for protection. Tropical hardwoods must be attached to the joists with special hidden clips.

Safety Considerations

Observe all safety recommendations that come with the power tools that you will be using. Height can be a safety concern when building elevated decks; even an elevation of a foot or two can be enough to cause injury.

What You'll Need

Equipment / Tools

  • Ratchet wrench set
  • Bubble level
  • Pencil
  • Circular saw
  • Chisel
  • Hammer
  • Tape measure
  • Cordless drill
  • Caulking gun
  • Mason's string
  • Scrap two-by-fours
  • Plumb bob
  • Post hole digger
  • Wheelbarrow
  • Hand saw
  • Garden hoe
  • Electric miter saw
  • Speed Square

Materials

  • 15 two-by-eights, pressure-treated
  • 2 six-by-sixes, pressure-treated
  • 3 two-by-sixes
  • Four-by-fours
  • Two-by-twos
  • Laminated LVL beam or two eight-by-eights
  • 2 notched staircase stringers, pressure-treated or ground-contact
  • 4-inch by 1/2-inch lag screws, with washers
  • Galvanized flashing
  • Exterior-grade caulk
  • 3 concrete tubes
  • 2 bags of gravel
  • Quick setting concrete
  • 3 J-bolts
  • 3 metal post anchors
  • 3 metal saddles
  • Joist hangers
  • 10d galvanized nails
  • Deck screws
  • 2 galvanized metal angle brackets

Instructions

  1. Size and Cut Ledger

    1. Use the bubble level and pencil to outline the shape of the ledger on the siding.
    2. Set the circular saw to siding depth and cut on the outline.
    3. With the hammer and chisel, cut away areas of the siding that the saw blade could not reach.
    4. Remove cut siding and dispose of it.
    5. Measure out the pressure-treated two-by-eight to the size of the cutout.
    6. Cut the two-by-eight.
  2. Attach Ledger to House

    1. Cut galvanized metal flashing to the length of the ledger.
    2. Install the flashing at the top of the cutout, under the siding.
    3. Attach the ledger with nails to the ledger cutout. Do not attach the nails to the house studs, as you need to reserve these for the lag screws.
    4. With the cordless drill, drill pilot holes for the lag screws, plus counterbores (to sink the heads of the lag screws). Do this at every other stud, two holes per stud.
    5. With the ratchet wrench set, drive the lag screws and washers into the studs.
    6. Using the caulking gun and exterior-grade caulk, caulk all around the ledger, including the lag screw holes and the flashing.
  3. Determine Post Footing Locations

    1. Measure outward 8 feet from the ledger to the general location of the three post footing locations.
    2. With the scrap two-by-fours, build five batter boards.
    3. Stake the batter boards outside of the expected dimensions of the deck: three at the end and one on each side.
    4. Run one mason's line between the two side batter boards, above the expected location of the post footings.
    5. Run three mason's lines from the ledger to each of the three end batter boards. The lines should be above the expected footer location.
    6. At the three crosses formed by the mason's lines, drop a plumb bob to the ground.
    7. Mark the location on the ground where the plumb bob touches. Leave the lines and batter boards in place for now.

    Tip

    Batter boards are temporary staking posts used for running lines. With this project, nail or screw together scrap two-by-fours to build five U-shaped batter boards. Each board should be 2 feet wide and 3 feet high. Cut the legs at angles for easier staking.

  4. Dig and Pour Footings

    1. Dig the three footing holes at the plumb bob marks. Dig below the frost line or as specified by code in your area.
    2. Add 3 inches of loose gravel to the bottom of each hole.
    3. With a hand saw, cut the concrete tubes to the depth of the footing holes, plus another 2 inches. Insert each in the footing holes.
    4. Mix concrete in the wheelbarrow with a garden hoe.
    5. Fill the concrete tubes with concrete to the top.
    6. While the concrete is still wet and pliable, insert J-bolts in each one, with the threaded side upward and about 1 inch exposed. Locate each J-bolt with the plumb bob.
    7. Remove the batter boards and lines.
  5. Attach Posts

    1. Place metal post anchors over each of the J-bolts on the footers.
    2. Place a nut on each of the threaded J-bolts and tighten it down.
    3. With the electric miter saw, cut three six-by-six posts. Each post should be the length of the distance between the top of the concrete footing and the bottom of the wood beam that will be later be placed on them, along with an extra 1 foot.
    4. Nail the posts into the metal post anchors.
    5. Plumb the posts. Set each plumbed post in place by staking it with scrap two-by-fours.
    6. Add the cut points on the posts. Do this by running a two-by-four as a mock joist from the ledger across to each post. Start the two-by-four at level, then drop the far end to allow for a 1/4-inch drop per 5 feet. This slope will let water drain away from the house.
    7. Mark the cut point on each post, using the bottom of the two-by-four as a reference point. Wrap the mark around the post with the Speed Square, but do not cut it yet.
  6. Install Beam

    1. If not using a laminated exterior-grade beam, create your own by clamping and gluing two two-by-eights together with construction adhesive and nailing them in place.
    2. Hold the beam up to the posts and mark post locations on the beam.
    3. With the circular saw, cut off the posts on the marks made earlier.
    4. Install the saddle hardware on the top of each of the posts. Be sure that the open saddles all run in the same direction in order to accept the beam.
    5. Insert the beam and attach the beam to the saddle hardware with galvanized screws.

    Tip

    Saddle hardware can be rather expensive, costing $50 to $75 each. But using saddles saves you from the alternate method: cutting notches in the posts.

  7. Build Header and Outside Joists

    1. Attach the two outside joists. Each joist will be placed at an end of the ledger. Use joist hangers to attach them to the ledger.
    2. Set the two outside joists in place so that they run from the ledge across to the beam and extending beyond the beam.
    3. Attach the header joist to the two outside joists. Do this by face-nailing through the header joist and into the outside joists.
    4. This outer frame of header and outside joists should be checked for square. Measure each diagonal; the two numbers will match if the frame is square. Adjust as needed.
  8. Hang Flooring Joists

    1. With the tape measure, mark off every 16 inches (or as specified by your deck plan) along the length of the ledger. Start at one of the outer joists, counting this as your first joist.
    2. Repeat the same measuring process on the deck's header joist.
    3. Nail joist hangers on-center at each of the marks.
    4. Cut the flooring joist two-by-eights to the specified length with the electric saw.
    5. Fit the joists into the joist hangers.
    6. Nail the joists into the joist hangers.

    Tip

    When attaching the joist hangers, nail just one side of the hanger. Place a short piece of scrap two-by-eight into the joist hanger. Close up the free side of the hanger and nail the hanger into place on the ledger or header board. Then, remove the scrap two-by-eight. While not necessary, this helps form perfectly sized joist hangers—ready for the joist to be inserted.

  9. Lay Decking

    1. Dry-fit the deck floorboards on the deck framework to get a sense of how many are required to fit the distance from the house to the header joist. The last floorboard should be flush with the edge of the header joist. Leave a 1/8-inch gap between floorboards.
    2. Starting at the house, attach the floorboards to the deck joists with deck screws.
    3. With the last five to six floorboards, you may need to slightly alter the floorboard gap so that the last board will be flush with the header joist. This is preferable to ripping the last floorboard to width.
    4. With the circular saw, cut off the ends of the floorboards so they are flush with the outer rim joists.
  10. Install Staircase

    1. Cut the notched staircase stringers to the required length.
    2. Attach the stringers to the desired location on the side of the deck, using the angled brackets. A common staircase width is 36 inches.
    3. Cut the two-by-sixes so that there are two per staircase tread (step).
    4. Use deck screws to attach the treads to the stringers. Space the two boards on each tread by 1/8 to 1/4 inch.
  11. Build Railing

    The quantity of rail materials to order depends on the size of the deck. Calculate each 6-foot linear stretch of deck railing as having two 36-inch four-by-four posts, one 6-foot two-by-four as a top rail, one 6-foot two-by-six at a railing cap, and 18 36-inch two-by-twos as balusters.

    1. For the railing posts, cut the four-by-fours to a minimum of 43 1/4 inches. This spans the width of a two-by-eight (7 1/4 inches) plus the minimum code-required height for deck rails of 36 inches.
    2. With the auger bit, bore two holes in each four-by-four to a depth of 1/2 inch in order to sink the lag bolts in the posts.
    3. Attach the railing posts to the side of the deck with lag bolts, lock washers, and nuts. Alternatively, you can use lag screws to avoid tightening nuts under the deck, if the deck is close to the ground.
    4. Run a two-by-four across the top face of the posts.
    5. Run a two-by-six along the very top of the posts, as a cap.
    6. Attach two-by-two balusters 4 inches apart from each other between the posts.

    To ensure your deck railing is up to code, follow these guidelines:

    • The railing must rise at least 36 inches above the top of the deck flooring.
    • Place posts no farther apart than 6 feet from each other.
    • Vertical balusters between posts should be no more than 4 inches apart—side-to-side, not on-center.

When to Call a Professional

Building a deck by yourself saves money, but it raises other issues. Do-it-yourself decks are easier to build when they are single-level and are square or rectangular. If you'd like other shapes, multiple levels, or accessories like benches, it may be best to hire professionals.

Second-story or other high decks can often stretch the limits of most do-it-yourselfers' skills, tools, and ability to gather similarly skilled helpers. Hire pros for tall or any complicated type of deck.