Make an accurate floor plan of the room on a sheet of graph paper. Use the scale "two squares equals 1 foot" for this plan.
Measure approximately 6 feet back from the planned screen wall to site your floor-level first seating section. This first seating section should be approximately 32-inches wide, the width of most couches and club chairs. Draw the second seating section, your first raised section. This raised section should be no less than 66 inches wide: 32 inches to accommodate a couch or chair width and a 34-inch aisle space for access and legroom. Add a second raised section if space permits. Transfer these seating sections back to the floor plan to check your overall design. Account for a center aisle space and entryways.
Calculate the raised seating platform dimensions. Each platform should be 66 inches wide by the desired length and should stand 6-inches high for the first raised section and 12-inches high for any second raised section.
Build a "picture frame" with standard 2-by-4 studs, to the correct dimension. Add cross supports every 12 to 16 inches on center along the length and width of the frame. Use angle irons to reinforce any joints. Cut "legs" for the platform to the finished height of the platform, minus ¾ inches. Install a 2-by-4 leg every 12 to 16 inches on center along the length and width of the frame. Attach the legs to the frame using two 3/8-inch carriage bolts per leg. Countersink the bolt heads.
Flip the platform on its legs. Adjust for level. If you intend to finish any sides of the platform with plywood, add ¾ inches to the top plywood panel dimensions for each side panel you intend to install. Cover the top of the platform with ¾ inches plywood. Attach the top with screws set 6 inches on center. Install any side panels. Cover the platform top and sides with appropriate floor covering material.
Move the platforms into position and install your seating. If the platforms seem to move or "walk" out of position too much, bolt or screw the sections together (out of sight) to form one large unit. You can also anchor the units to the wall or floor.
Construct a step for any second raised section if desired. If your second tier is 12 inches high, build a step 6 inches high by 11 inches wide, by the length desired. This will be a safe and comfortable step unit.
Things You Will Need
- Graph paper
- Measuring tape
- 2-by-4 pine or fir lumber
- 3/4-inch A/C plywood
- 2-1/2-inch wood screws
- 3-inch angle irons
- 1-1/2-inch wood screws
- 3/8-by-4-inch carriage bolts
- 3/8-inch nuts
- Floor covering material
- Power tools
- Platforms can be heavy and hard to maneuver so construct the platform(s) inside the theater room. Consider leaving sides that "won't show" uncovered for easier moving.