Building a free standing deck is easily accomplished with the proper tools and materials and a little instruction. This article will discuss the basic procedure for constructing a sturdy, level, durable free standing deck. There are many composite decking, railing and fencing materials currently on the market at a much higher price than ordinary lumber. The advantages of using composite materials are that they are low-maintenance, resilient, authentic in appearance and the deck will almost certainly outlive the owner. Consult the manufacturer’s specifications for installation instructions and fastener techniques for the product of your choosing. If you decide to go with wood, remember that pressure-treated lumber is required for any wooden structure that is exposed to the elements or in contact with moisture, the ground or concrete.
Tools and Materials Needed
- Cylindrical cardboard forms (one for each post)
- Ready-mix concrete
- Post hole digger
- String line
- Framing hammer
- Anchor bolts
- Galvanized #8 nails
- Galvanized #16 nails
- Circular saw
- Decking material: lumber or composite (frame, decking, railing, posts)
- Joist hangers
- Bolts, nuts, washers
Step 1: Build the Foundation with Deck Footings
The most expeditious and economical way to support the deck is with individual concrete footings. The deck frame will include vertical supports or posts (4 x 4 or 6 x 6); each post bears on a separate concrete footing. The footings are poured into 12-inch diameter cylindrical cardboard forms set in holes dug deep enough to penetrate the frost line. An anchor bolt 6 inches long is placed in the center of the form extending about an inch above the top surface of each footing. A 3 by 3-foot (minimum) concrete pad will be needed at the base of the deck stair for the landing. Pour the pad over a 4-inch layer of compacted gravel; the pad itself will have a thickness of 4 to 6 inches.
Step 2: Install the Posts
The base of each post is secured to a bracket, which is anchored to the top of the footing. When the concrete has set, fasten the bracket onto the anchor bolt with a nut and a washer and secure the posts to the brackets with #8 galvanized nails. Use a level to make sure that the posts are plumb before starting work on the frame and check them periodically.
Step 3: Assemble the Deck Frame and Install the Decking
The decking will be supported by horizontal ribbon joists or “bands” that are bolted to the posts at the desired height. Larger decks will require cross beams that bear directly on the posts; the joists will in turn be supported by the cross beams. The joists will run in a direction parallel to the short dimension of the deck and will attach to the band with joist hangers. Decking is typically available in nominal dimensions of 5/4 x 6 inches. The decking will be fastened onto the band joists with #16 galvanized nails or deck screws, overhanging a short distance along the perimeter. Layout and cut the stair stringers; use decking to install the treads.
Step 4: Construct the Railing
For smaller decks, the posts can extend all the way up to form the end posts for the railing. The railing will consist of a top rail or cap, a bottom rail and 2 x 2-inch balusters at 5 inches on center. The top rail is generally required to be 36 inches above the deck floor.