Project Guide

How to Build a Deck

Ground-Level Deck: Dig Holes for Posts
A tube form is leveled for a concrete deck footing.

These instructions review how to build a deck that will be approximately 8 feet wide and 10 feet long. This assumes the deck will be on level ground and not attached to your home, with an estimated building time of 16 to 24 hours. 

  • Begin by using batter boards and mason's string lines to lay out the location of the footings, which will provide the deck’s foundation. 
  • Use a posthole digger or power auger to dig six holes for footings of 8 inches in diameter and 12 inches deep. They should be in rows parallel to each other. 
  • There is no frost line since this is a freestanding deck. Place concrete tubing forms in the holes and level the footings about 1 inch above ground level. 
Pour Concrete and Place Post Anchors
Two people align anchors for deck posts.
  • Mix six 60-pound bags of ready-mix concrete in a wheelbarrow. Pour cement into the footings, then place post anchor bolts into the center of each footer before the cement begins to harden. 
  • Backfill hole with gravel around the tubing forms. 
  • Align anchors with a long straight board. Check diagonal measurements to square the anchor positions. 
  • Allow concrete time to cure according to manufacturer’s instructions.

Tip: Leave enough of the bolt above the footer to connect to the anchor. 

Attach Beams to Post Anchors
Beam attached to post anchor with hammer and nail.
  • Use double 2- x 6-inch deck boards as framing beams. Attach them within the post anchors with nails or structural screws. The anchor is 3-1/2 inches wide and the beam is 3 inches thick, so install a 1/2-inch-thick pressure-treated shim between the beams and one side of the anchor at each footing. 
  • Check beam alignment and adjust as necessary to make certain beams are square. 
Attach Rim Joists and Angle Brackets
Rim joist attached to beam with power drill.
  • Using a power drill, attach 2- x 6-inch rim joists to the ends of the beams. 
  • Install angle brackets to provide additional support for the corner joints of the frame.
Attach Inner Joists to Beam Faces
Inner joist attached to beam with hammer and nail.
Install Boards and Add Fasteners to Joists
Deck board attached to joist with a power drill.
  • Align the edge of the first length of decking with the outside edge of the beam. 
  • As you install the decking boards perpendicular to the joists, drive two fasteners through each board into the center of each joist. Position each fastener 3/4 to 1 inch from the edge of the board. 

Tip: For the best appearance, stagger the seams between adjacent rows of decking. 

Trim Deck in a Straight Line
Power saw trims deck boards.
  • Snap a chalk line to mark a straight cutting line along the edges of the deck. 
  • Cut decking to length with a circular saw to insure the edges are uniform. 
Raised Deck: Lay Out Footings and Attach the Ledger Board
Man lays out footings for raised deck.

These steps outline how to build a raised deck that is 24 feet long and 14 feet wide, intended to be attached to a house and sturdy enough to accommodate future additions such as a roof. 

  • Use batter boards and mason’s string lines to lay out locations for seven support footings of 12 inches in diameter. 
  • Determine height of deck and attach a 2- x 12-inch ledger board to the house to establish the deck position. Remove siding from exterior wall if necessary. 

Dig Holes for Footings and Set in Concrete
Man aligns anchors for concrete footings.
  • Using a power auger, dig 48-inch deep holes for the seven footings, which will be able to bear the weight of additions to the deck. 
  • Flare the bottom of the center footing in the row parallel to the house to 24 inches. Flare the remaining footings to 18 inches. 
  • Mix forty-four 60-pound bags of ready-mix concrete in a portable power mixer. 
  • Pour concrete by method in Step 2.
  • Install and align anchors for 6- x 6-inch posts after the concrete has cured for 48 hours. 
Plumb and Brace the Posts
Braces support deck posts.
  • Secure the 6- x 6-inch posts to the anchors with structural screws or nails.
  • Plumb and temporarily brace the 6- x 6-inch posts in place with diagonal support beams.
  • With a power saw, trim post tops to the proper height after positioning. Using a level, establish trimming lines that are aligned with the bottom of the ledger board. 
Build Beams on Top of Posts
Beams attached to top of posts.
  • Build a 24-foot beam made of doubled 2- x 12-inch boards with nails driven about 8 inches part. Place on top of the row of posts parallel to the house. 
  • Attach beam to the tops of the posts using adjustable post caps. This beam serves as the header joist because joists will be attached to its inner face. The two rim joists will also serve as deck beams to help carry the weight of future remodeling. 
  • Build in place the additional beams 14 feet long. The remaining length will support the landing at the top end of the stairs. 
  • Attach the end of the adjacent 14-foot beam to the ledger board with a double joist hanger. 
Install the Inner Joists and Rail Posts
Joists installed on raised deck.
  • Determine the spacing of the inner joists according to building codes and mark on the beams. Install 14-foot long 2- x 12-inch joists. 
  • Use joist hangers to attach joists to the ledger board and beam header joist with deck nails or screws.
  • Fasten blocking pieces between joists in the middle of the span to prevent twisting. 
  • Most of the temporary bracing can be removed from the posts after joists are installed. 
  • Determine locations of railing posts, including at the corners by the house, at the outside corners and at the top of the stairs, according to building codes. 
  • Install railing posts along the outside of the deck framing using deck anchors attached to the joists. Secure the posts with carriage bolts.
Install the Decking and Railings
Man installs deck boards.
  • Attach five 4- x 6-inch decking boards perpendicular to the joists and fasten with deck screws. No additional blocking is necessary because seams between boards should be centered over joists. 
  • Install 2- by 4-inch railings along the back side of the rail posts, including a bottom rail three inches above the decking and a top rail flush with the top of the posts.
  • Secure wood balusters to top and bottom railings along the outside of the deck with wood screws.

Tip: For the best appearance, stagger the seams between adjacent rows of decking. 

Locate Footings for Stair Landings and Set in Concrete
Footings for deck stair landing set in concrete.
  • After building the main deck platform, locate the footings for the stair landings and pad: it will be more accurate to measure relative to an existing deck structure.
  • Mix thirty-two 60-pound bags of concrete in a portable power mixer for this step. 
  • Make one 12-inch diameter footing for a 6- x 6-inch post to support the upper landing, as per the earlier method in Step 2.
  • Make four 8-inch diameter footings for 4- x 4-inch posts to support a small transition landing in the stair run. The stair run will make a 90-degree turn at the landing to end on the 4- x 4-foot pad. 
  • Dig out a 4-inch deep, 4- x 4-foot hole and insert a matching wooden frame. Pour cement into the hole to make a landing pad 4 inches thick. 
  • Attach post anchors to the footings as per Step 3.
Raise the Landings and Build the Stairs
Deck stairs built on posts.
  • Plumb posts and install the framing for the staircase landing. 
  • Attach decking to the joists. 
  • Calculate size of the stair runs and make stringer supports for the stairs. Stairs should be at least 36 inches wide. Space the stringers about 12 to 16 inches apart. 
  • Secure the top of the stringers to the deck with hangers. 
  • Build the upper and lower stair runs in place with decking planks for treads (and toe kicks if desired). 
  • Secure the bottom of the stringers to the concrete landing pad by attaching cleats between the stringers, and securing them to the pad with anchor bolts.
Install the Staircase Railings
Rails installed on deck staircase.
  • Calculate the staircase railing post locations, notch posts and attach to the outside of the stringers. 
  • Install the staircase railings and balusters according to the method from Step 13.
  • The two posts at the bottom end of the upper stair run should be longer than other posts because they also serve as posts for adjoining railings – this will save the time and cost of installing two additional posts. 

Learning how to build a deck, whether a relatively simply ground-level platform or a more complex raised deck with rails and a staircase, requires a command of basic carpentry and a commitment of time and resources. Once completed, a deck adds value to your home and helps you enjoy the outdoors in greater comfort.

For help with installing your deck, contact the experts at the The Home Depot Installation Services department.