Cushions are often the first part of a couch to show wear, and replacing the cushion filler can rejuvenate the whole sofa. Sheet foam or foam chips break down and disintegrate, and fiberfill will lose its resilience and loft. Replacing the filler begins with deciding how firm you want the cushions to be after restuffing. Most sofa cushions have a zipper to make removing and restuffing easier. If there is no zipper, carefully snip the threads of a seam that faces the back of the sofa, restuff the cushion and sew the seam closed.
The most common stuffing in couch cushions is sheet foam. The firmness and density of the foam determines how soft the cushions will be and what lifespan can be expected. Most foam sofa seat cushions have a density of 1.13 Kilogram per cubic foot. The most common firmness is 35, indicating that 15.9 Kilogram of pressure must be applied to force 12 inches of foam down to 8 inches. Sheet foam is priced based on thickness, firmness, density and expected longevity. High-quality foam can be expensive compared to fiberfill or foam chip stuffing.
Foam chips produce a much looser cushion than sheet foam. The chips are produced from foam and can be purchased based on similar criteria. Foam chips are available in soft, medium and firm densities and must be enclosed in a fabric case before inserting into a cushion. Cushions of foam chips should be generously overpacked because the filler will pack down initially. This filler is less expensive than sheet foam, but the life expectancy is shorter.
Polyester fiberfill is a man-made substitute for down that should be enclosed in a fabric case before placing in the cushion. Cushions stuffed with fiberfill will often appear to be down cushions; they will not have a uniformly flat surface and will be soft when sat on. Fiberfill will pack down under pressure and may not rebound fully, rebounding less each time. It is not recommended for use alone as seat cushions on a sofa.
Often two or more fillers are used together to produce a high-performance cushion filler. Bonded terylene, a quilt-bat like material, is wrapped around sheet foam, adding softness to the edges, loft to the centre, and reducing friction of fabric against foam. Firmness in fiberfill or chip cushions can be increased by positioning a piece of very firm foam in the middle of the insert.