DIY Island Deck

Remove any furniture, stones or slabs from the area where the deck is to be built. Dig out any grass in the area using a shovel. Dig down 6 inches into the ground using the shovel. If the island deck is being built near a building, dig down 6 inches at the side closest to the building and 8 inches at the opposite end, then slope the ground in between the two.

Compact the ground using the plate compactor to create a solid surface to support the deck. If you have sloped the ground, ensure the compacted ground remains sloped rather than allowing the compactor to level it off. Dig a 1-foot-deep hole every 1 foot along the length and width of the area using the shovel, for the deck support posts to sit in.

Measure and cut enough lengths of 2-by-4 18 inches in length using a circular saw, to create enough support posts to fill the holes you have dug. Varnish each post using-exterior grade varnish and a paintbrush. While the varnish is drying, measure the length and width of your deck area using a tape measure. Note the measurements on a piece of paper.

Cover the compacted ground with sheets of polythene. Cut holes in the polythene where the holes for the support posts are, so the posts can push through the sheeting. Mix a batch of concrete from 1 part cement, 3 parts sand and 1 part water. Plant the support posts in the holes you dug for them. Pour cement into each hole to hold the posts in place. Allow 48 hours for the cement to set.

Pour gravel onto the polythene sheets and rake it all flat so it is level with the surrounding ground. Measure and cut two 2-by-4 timbers to the deck length you recorded earlier, using a circular saw. Cut two more 2-by-4 timbers to the width of the deck as recorded earlier.

Draw a 1-by-1 inch square on each end of the 2-inch-wide faces of the 2-by-4 timbers. Cut out these squares using a hacksaw to leave 1-by-1-by-4-inch cutouts. Apply wood glue to the cutouts. Fasten the timbers together by the cutouts to form a rectangle with basic mortice joints in the corners. Reinforce the joints with a hammer drill and screwdriver drill bit to place two countersunk long screws per joint.

Determine which is shorter, the length or the width measurement of the deck. Cut enough 2-by-4 timbers to this shorter length less 4 inches to place a support brace every 2 feet along the inside of the rectangle you just built. Screw the support joints to the inside of the wooden frame using 2 countersunk long screws per joint. You will now have a rectangular frame with support beams every 2 feet along either its length or width.

Varnish the frame with exterior-grade varnish. Allow the varnish time to dry. Raise the frame onto the deck support posts. Screw the frame to the posts using L-brackets. Arrange decking on the top of the frame so the frame is fully covered. Screw the decking slats in place on both the frame and the support beams running through the inside of the frame. Varnish the decking with exterior-grade varnish and a paintbrush.

Decide where the steps shall be placed for the deck. Cut four pieces of 2-by-4 timber 5 inches long. Cut two pieces of 2-by-4 18 inches long. Screw one of the 5-inch pieces to the end of one of the 18-inch pieces using a countersunk long screw, so the 5-inch piece stands vertical and the 18-inch piece is horizontal.

Screw another 5-inch piece to the other end of the 18-inch piece. You should now have two 5-inch pieces standing vertically with a distance of 16 inches between them, and an 18-inch piece screwed in front of them. Screw another 5-inch piece onto the back of each 5-inch piece.

Screw the remaining 18-inch piece in front of the first 18-inch piece. You now have the frame for your steps. Lay decking slats on top of the pairs of 5- and 18-inch pieces. Screw the slats to the step frame to complete the steps. Varnish the steps. Allow the varnish to dry. Attach the steps to the deck support posts using L-brackets.