Pier blocks make it easy to create a freestanding deck that is not connected to the home. The average do-it-yourself homeowner with minimal carpentry skills can easily create a good-looking, functional deck in a day's work. A 12-by-8 foot freestanding deck requires no sawing or hammering with a simple ladder frame and pier blocks.
Lay out the concrete pier blocks into six columns and three rows. The columns should measure 11 feet, 10-1/2 inches from the center of the first pier to the center of the last pier, with the piers spaced approximately 28 inches apart. The rows should measure 6 feet from the center of the first pier to the center of the last pier, with the piers spaced 3 feet apart.
Check the square of the foundation by placing an 8-foot-section of lumber onto the first and last row of blocks then using a 12-foot-section to mock out a simple wood rectangle. The end pieces of each wood section should meet and be square, according to the carpenter's square. If not, adjust the piers accordingly.
Tape a cord to the top of the first pier on the first column and extend it to the top of the last pier in the column. Measure the level of the cord with a bubble level. If a pier needs to be adjusted to create a level line along the column, then remove or add some dirt under the pier as necessary. Always pack down any added dirt with a tamper. Continue to level each column the same way until the structure is level along the columns.
Move the cord to the first row and ensure that each row is level in the same manner. If you adjust a row pier, you will have to go back and remeasure the level for the column it is in to make sure it hasn't changed as well. Continue to measure and adjust until the entire foundation is level.
Fill in the spaces between the concrete pier blocks with landscaping fabric wrapped around the interior foundation piers. Add 1 to 2 inches of gravel on top of the foundation. This will prevent grass and weeds from growing under the deck and provide drainage to keep it from holding moisture in the shade of the deck.
Place six of the 8-foot sections of lumber into the slots on top of the piers along each row with an equal amount of wood hanging over each of the six piers along both sides. Since this is a ladder frame, these are the "steps" in the ladder.
Set one of the 12-foot lumber sections along the butt end of the 8-foot boards. This will be the "side" of the ladder. Check the square again on each end with the carpenter's square
Install three screws through the 12-foot lumber section and into the butt end of each 8-foot section. Have an assistant on the other end of the 8-foot boards press each one against the 12-foot section to make the job go faster. Attach another 12-foot section to the other side of the deck in the same manner to create a completed ladder frame.
Place the first 12-foot section on top of the ladder frame and against the end. Square the section corners with the carpenter's square then screw through the section into the frame below along the length of the section. Add the next section to the frame and butt the corners together tightly. Screw that section down as the first one. Continue to add sections until the deck is finished.