A wedged seat, sometimes referred to as a Perch Seat, is angled so that the back is higher than the front. This 7 to 10 degree angle tips the pelvis into an anterior tilt which can prompt upright posture. The wedge promotes “active sitting” during which the core muscles are engaged and the sitter is alerted to engage more attentively with presented activities. Children with low muscle tone who slouch may be good candidates for wedged seating.
The size of a simple perch seat will be based on the size of the child to ensure that the child’s feet will be flat on the floor and that the seat is high enough for the angled top ot do its magic.
A: The distance from the back of the child’s knee (in sitting) to the bottom of the foot.
B: The distance from the back of the child’s knee (in sitting) to the back of the buttocks plus an inch or so.
C: The distance across the widest part of the child’s hips (in sitting) plus about 2 inches.
D: The height of the back of the support pieces after you determine the angle (you will not need to know this measurement when you are measuring the child, it will be calculated later).
The perch is made up of a total of 5 pieces of cardboard, one long piece that will be bent to form the front, top, and back of the perch (#2 in the photo above). Three pieces (#1), which make up the two for the sides and an extra piece to place in the center of the perch for additional support and a piece that will form the base of the entire structure (#3).
Start by drawing out the first side piece. Make sure you orient the flutes in the corrugated material so that they run up and down so as to better support weight.
In planning the size of this piece we need to account for the thickness of the material that will run around it. The cardboard that we use is typically 5/8 inch thick. Therefore we are subtracting 1 ¼ inches from both A and B.
Meaure A (minus the thickness allowance) first. Then mark what a 7-10 degree tilt is up from that point.
Meaure out B (minus the thickness allowance) along this line. You will then drop a line straight down from the back point, making sure that you have a right angle at the bottom.
Cut out this piece and then cut two additional identical pieces, making sure again that the flutes run up and down. Make sure all three support pieces are exactly the same.
Next cut one long strip that will become the front, top, and back of the perch (#2).
The desired width of piece #2 will be measurement (C), and the length will be measurements (A + B + D + 2 inches). The additional 2 inches is to ensure that it is long enough when it is bent to fit around the supports. Cardboard bends more easily when you fold it along the flutes, so make sure that the flutes run across the strip.
Once the piece is cut, measure in from the end (A) minus the thickness allowance of the base and the top. In our case it would be (A) minus 1 and 1/4 inches.
Make another line about 1/4 inch to 3/8 inch parallel to this one (dotted line in the photo above). Use a blunt tool (like the back end of a spoon) to make an indentation along this line.
Turn the piece over and line up the indentation just off the edge of the table. Push down to fold.
Draw a line where the end of the folded part is and measure from here (B) minus the thickness allowance (1 and 1/4 inches).
The back bend is more severe, so it will take up more space. To account for this increase mark the line for scoring about 1/2 inch from this line (dashed line).
Score with a blunt object (back end of a spoon), position on the edge of the table, and fold.
Wrap the long bent piece (#2) around one of the supports and mark the spot where the back should end. Once you mark each end of piece (#2) draw a line and trim the excess cardboard.
Glue the two sides and the middle support into place.
Use clamps to hold the parts in place until glue cools and becomes hard.
Measure (or trace) the perimeter of the bottom and cut piece (#3) that will form your base.
Once you ensure the base piece lines up with the edges of the top structure of the perch glue it into place.
Tape or paper the edges of the corrugated material, and proceed to pain and decorate the perch so that it will be appealing to the intended user!