1. WIDTH and DEPTH: measure the width and depth of the chair. Use this depth measurement even if the chair is deeper than appropriate. If the seat is too deep, a back support (directions included) should be made which will sit on top of the built-up seat and lessen the depth of the chair.
2. HEIGHT: subtract the present height of the chair seat from the desired height of the chair seat.
1. Cut out the rectangles of Triwall and polyurethane (soft) forma that match the width and depth measurements of the chair. Cut the Triwall using a razor knife, steak knife, band saw or jig saw, and the foam with a heavy-duty scissors.
2. Cut out a rectangle of the vinyl material that is approximately 7 inch longer and 7 inch wider than the size of the Triwall (or add 3 ½ inches to each of the four sides), for allowance in folding the vinyl over the back of the Triwall. If a layer of polyethylene (hard) forma is to be added (see step #4 below), the vinyl material should be 12 inches longer and 12 inches wider than the Triwall (add 6 inches to the four sides).
3. If the thickness of the Triwall and polyurethane (soft) foam combined raises the chair seat to the desired height, proceed to cover them with the vinyl:
a. Lay the vinyl face down on your work surface. Center the foam on the vinyl. Then lay the triwall on top of the foam, so that the edges are aligned with the foam.
b. Now begin stapling the vinyl to the back of the Triwall, using a heavy-duty staple gun. For best results, anchor the center of each side with a few staples to hold all parts together, and then work outward towards the corners.
c. Overlap corner fabric and staple down. Trim off the excess vinyl material after stapling.
4. If the thickness of the Triwall and polyurethane (soft) foam combined does NOT raise the chair seat to the desired height, than add a piece of polyethylene (hard) foam (same dimensions as the Triwall) or an additional piece of Triwall between the Triwall base and polyurethane (soft) foam. Then cover with vinyl material as described in step #3.
1. Wedge-Shaped Built-Up Seat: Use an electric carving knife to carve an angle into the polyethylene (hard) foam described in Step 4. The thickest part of the wedge should be at the front of the seat. Then follow Steps 1 through 3 to assemble and cover the seat. The size of the polyurethane (soft) foam may need to be adjusted once the wedge shape is cut.
Be sure chair is the correct size for the student WITH the wedge in place.
2. Built-Up Seat with Thigh Guides: Carve the polyethylene (hard) foam describes in Step 4 so that is has lateral walls, using the electric carving knife. Then follow Step 1 through 3 to assemble and cover the Seat. The size of the polyurethane (soft) foam may need to be wider to compensate for the curvature of the seat.
Designed by JoAnn Kluzik, MS, PT, PCS, Physical Therapist, while working at Cotting School