If you have one of grandma's chairs in the attic that needs a new rush seat, you do not have to have a professional reseat it. It requires a lot of patience, but you can reseat a rush chair at home.
Cut a twelve foot section of rush. Untwist the end slightly and tack it to the top of the left side rail near the corner post.
Wrap the rush over the top of the front rail, bring the rush under and back over the top the left rail where you began. Bring the rushing under the rail and over the top of the opposite side rail.
Pull the rush tightly as you weave. Pull the rush across and over the right side rail, bring it under and come back to the top, over the rush you just pulled from the left and pull it over the top of the front rail, pulling it toward the back rail.
Attach the rush to the back rail in the same method, looping it over the top and bringing it under. This time loop back over the rush and the right rail. Bring it under and loop it over the left rail. Bring the rush under and up, and loop over the rush you just laid and the back rail.
Adjust the rush as close to the corner as possible. Wrap the rushing around the back rail and stretch the rush to the front rail, loop over, under and over to the left rail and you're about to begin row two. Continue rows in this fashion making certain they are close together.
Create padding from cardboard, to prevent wear. After you complete a few rows, cut diagonals to fit the four corners from eight rectangles of cardboard, two for each corner. These should not be more than 1/3 the width of the chair, and less than half of the length, since they should not overlap.
Stop periodically to use the evener to make certain rows are close and evenly spaced (dressed) on all sides.
Bring the cord up through the center when you have filled the chair seat. Dress the rush so that there is room to stretch the cord over the front rail to the underside of the seat.
Turn the chair over and loop tightly under an opposite strand and tie with a half hitch. Pull the half hitch tight and do three or four more times.
Cut away excess cord and tuck the knot into the center to be covered by the weave.
Dress the entire chair, top and bottom, making certain that no loops over the rail protrude above the others.
Brush on tung-oil sealant to both the top and bottom. Let it stand fifteen minutes, wipe off excess and dry overnight.
Always keep the rushing pulled tightly.
When tying off the rushing, it's of utmost importance to keep it pulled tight. A second set of hands is advisable.