Examine the underside of your couch. Note whether it sits on legs and whether the legs can be removed by twisting. Note whether the frame is wide and sturdy enough to screw legs into if it does not have any, or whether there is room to add corner blocks to provide support for them.
Place sections of 4-by-4 inch wooden posts, paving bricks or concrete blocks under the corners of your couch as long as you do not have infants, toddlers or pets in the home. Secure the posts to the frame of your couch using 6-inch-long wood screws to prevent them from shifting and trapping a child or pet. Turn the posts, bricks or blocks on a diagonal at each corner for greatest support.
Use furniture risers if your couch already has legs. Measure the diameter of the leg to ensure that it will fit into the riser.
Clamp the risers around each leg or place them under each one, depending which type riser is available. Check the risers each time you sit down to make sure the couch legs are fully seated in the recess to avoid slippage.
Remove any twist-off couch legs and replace them with longer ones. Cut the bottom portion from twist-on table legs on a table saw if couch legs are not available in the right length.