Step 1
Turn the chair upside down with the bottom of the chair facing up. Depending on the manufacturer, the chair may feature screws or nails that keep the seat attached to the chair frame. Remove the seat from the wooden chair frame by unscrewing it from the frame using a screwdriver. If the seat had been nailed to the frame instead, remove the nails using a hammer or a pair of pliers, taking extra care not to crack the wood as you pull the nails out.
Step 2
Turn the seat upside down to reveal the staples holding the fabric to the seat. Slide the butter knife under the edge of any staples holding the fabric in place and pop the staples loose.
Step 3
Peel away the fabric from the seat and set it to one side. Slide the edge of the utility knife under the original padding and wiggle it from side to side. Push the knife around, loosening the padding until it comes off the bottom board or backing.
Step 4
Sand the bottom board with medium-grit sandpaper, removing any glue residue left behind. The glue holds the padding to the board. Set the board on top of the foam and trace around the board. Trim the excess foam away, following the line you made.
Step 5
Coat the bottom of the foam with spray adhesive, which makes the foam slightly tacky. Spray more adhesive on the board itself. Set the foam directly on top of the board and press it down gently, letting the glue adhere the pieces together.
Step 6
Arrange the fabric over the top of the foam and board. Drape the fabric over one side of the pieces and turn it around so that you can see the bottom. Staple the fabric to the board and pull the fabric down taut on the opposite side. Add more staples and repeat on the other two sides, pulling the fabric taut and smooth as you staple.
Step 7
Reattach the seat back to the wooden chair frame using the screws or nails you had removed previously.