Clear out the room and measure the floor. Roll out the rubber flooring and mark cut lines on the flooring slightly larger than the dimensions of the room. Cut the material using a utility knife with a hook-blade attachment by fitting the hooked part of the blade over the edge of the flooring and pull it smoothly to cut.
Lay out the rubber flooring in the room, lining up the straight factory edge of the material against a wall. Work the flooring into place, smoothing out any air bubbles.
If there are posts or columns in the room, roll back the flooring and mark the size and location of the opening on the underside of the material. Make several cuts across the outline like slicing a pie. Also cut a straight line from the hole to the edge of the flooring that will rest against the wall. Roll the flooring back into position and smooth it around the post.
Slip a scrap of plywood under the flooring before cutting the hole to protect the material below. Cut holes in the flooring a little small for a tight fit. The holes can always be made larger if needed.
Once the flooring is completely in place, trim away any excess around the walls.
Choose a threshold ramp that fits the height of the threshold. They come in sizes up to 4-3/4 inches high. The ramp used in this project was made from recycled tires. Position the ramp sections around the threshold and mark for cuts to accommodate the door jambs. Use a jigsaw to make the necessary cuts, cleaning up the cut edges with a utility knife.
Dry-fit the ramp sections around the threshold. Trace around the ramp section on the indoor side of the threshold and use a hook-blade utility knife to cut away the rubber flooring underneath the section.
Spread construction adhesive on the subfloor and glue down the indoor ramp section. Apply pressure to the piece for up to three hours. Repeat the process for the outdoor section of the ramp.