DIY Carport Deck
Constructing a freestanding carport deck can serve a dual purpose for your home. The carport creates an open-sided shelter for your vehicles, while blocking them from the sun and much of the moisture they'd be exposed to being parked outside. Placing the carport next to your home in a location where you can install an exterior door on your second floor, allows you to use the carport's roof as a deck for entertaining friends and family. Using this structure for both purposes can keep other sections of your property open for other uses.
Building the Carport
Spray paint the ground to mark the outline of the carport deck. In this example, the deck will measure 15 feet long by 15 feet wide.
Measure the height between the ground and the bottom edge of the doors that will open to the carport. This determines the height of the posts for the carport.
Cut the posts for the carport from pressure-treated 4-by-4 beams. There will be seven exterior posts and two interior posts. Cut the two interior posts to match the height of the bottom edge of the door, plus at least one-third of that length, since at least one-third of the post must be placed into the ground for stability.
When cutting the exterior posts for the deck, add the required height of the deck rails to the length of the posts. Follow local building codes regarding the height of the railing. Wear safety goggles when sawing the wood.
Dig the nine holes for the posts into the ground in a grid pattern. Space them 5 feet apart. Dig the hole deep enough to accommodate at least one-third of the post's height, plus a 6-inch layer of gravel. Renting an augur can make this process much faster than using a shovel.
Place waxed fiber tubes inside each post hole to act as forms for the concrete footings. Pour 6 inches of gravel into each tube and tamp it down.
Drive a wooden stake into the ground next to each post hole. Tie strings to each stake to form a grid going across the area where you're building the carport. The strings are a guide for setting the posts into the ground.
Mix concrete following the instructions on the packaging. Pour 1 foot of concrete into the tubing in the first hole. Insert the first post into the waxed fiber tubing, pushing it against the gravel in the bottom of the tube.
Align the post with the strings. Check it for plumb (vertically straight), using a carpenter's level. Fill the rest of the tubing with concrete and check the alignment of the post again.
Set the rest of the posts into the ground, using the same method you used for the first post. Allow the posts to set in concrete for the time specified on the packaging. When setting the posts, remember to use the two shorter posts in the center post hole, and the post hole in the center of the carport immediately adjacent to the house. The taller posts are placed along the outer edges of the carport.
Backfill the gap between the footers and the ground with dirt.
Place a 15-foot long 2-by-8 beam against the posts that run adjacent to the house. Position it so the top edge is about 2 inches beneath the bottom of the doorway and clamp it in place. Place the beam along the inner edge of the posts, opposite the side where the house is situated.
Attach the beam to the posts by drilling two 1/2-inch holes through the beam and the posts. Insert 1/2-inch galvanized bolts through the holes and secure them with 1/2-inch galvanized nuts. When drilling the holes, offset holes in each post slightly so they're not in vertical alignment to help prevent the wood from splitting. Remove the clamps when you are done.
Install 2-by-8 beams around the perimeter edges of the posts on the other three sides of the carport. When installing these beams, place them on the outer edges of the posts instead of on the inner edges as you did for the first beam.
Install two beams that are 2-by-8. Run these across the three center posts that are parallel to the house, by placing one beam on each side of the posts. Attach the beams to the center post with the 1/2-inch galvanized nuts and bolts.
On the outer edges of the beams, place a galvanized angle bracket in the corners where the center beams and perimeter beams intersect. Screw the angle brackets to the beams with galvanized screws.
Nail galvanized joist hangers to the inner edges of the beams between the center beam and the beam that runs adjacent to the house. Also do this for the second center beam and the beam that runs along the front edge of the carport. Space the joist hangers no more than 12 inches apart.
Cut the joists for the deck floor using 2-by-6 boards. Slide these into the joist hangers. Nail the joists to the joist hangers with galvanized nails.
Cut decking boards for the deck floor. Install them by driving galvanized screws through the decking boards and into the beams and joists.
Installing the Railing
Measure the distance between each post around the perimeter of the deck so you know how long to construct each section of railing for the deck.
Cut a 2-by-4 board and a piece of top handrail to fit between the posts in the first section. The 2-by-4 is used along the bottom of the railing. The top handrail is used along the top of the railing. The underside contains a groove where the top edge of the spindles is placed.
Cut the spindles to the height required by your local building codes.
Mark the location of the spindles onto the bottom edge of the 2-by-4 used for the bottom rail. Space the spindles following local building codes.
Install the spindles by placing them along the top edge of the bottom rail. Drive 3-inch deck screws through the bottom of the rail and into the bottom edge of the spindles.
Place the top rail with the grooved edge facing up, putting the top edge of the spindles into the groove. Attach the top rail to the spindles by toenailing them with a nail gun. Toenailing involves driving a nail through each spindle at a 45-degree angle so it goes through the spindle and into the bottom edge of the top handrail.
Assemble the other railing sections. Use the same method you used when assembling the first section.
Apply a coat of primer to the railings and allow it to dry. Apply the primer with smooth, even strokes. Prevent the primer from beading up along the edges of the railing by running over them with the paint brush.
Paint the railing with two coats of paint. Allow the first coat to dry before applying the next.
Cut two small wooden blocks to match the height at which the bottom rail will rest off the deck floor.
Place one wooden block onto the deck floor next to the posts in the first section.
Measure and mark the midpoint of the posts where the railing is being installed. Measure and mark the midpoint of the top handrail along each side.
Place the railing onto the wooden blocks. Align the marks on the top handrail with the marks on the posts.
Attach the railing to the posts by driving finish-head screws through the bottom rail and top handrail, and into the posts at a 45-degree angle.
Install the other sections of railing using the same process.
Fill the holes over the screws with wood putty and sand it smooth. Prime and paint the patch.
Things You Will Need
- Spray paint
- Tape measure
- Pressure-treated 4-by-4 beams
- Circular saw
- Safety goggles
- Waxed fiber tubes
- Wooden stakes
- Carpenter's level
- Augur (optional)
- 2-by-8 beams, 15 feet long
- 1/2-inch drill bit
- 1/2-inch galvanized bolts
- 1/2-inch galvanized nuts
- Galvanized angle brackets
- Galvanized screws
- Galvanized joist hangers
- Galvanized nails
- 2-by-6 boards
- Decking boards
- 2-by-4 boards
- Top handrail
- 3-inch deck screws
- Nail gun
- Paint brushes
- Finish-head screws
- Wood putty
- Putty knife
- Cut the top edges of the 2-by-4s on the bottom rail at an angle that slopes away from the railing to assist with water runoff.