Springs and webbings

A number of suspension systems are used for upholstered seating The most common assembles for sofas today are a series of serpentine or zigzag springs, or elasticated webbing made from either rubber or fabric. Other spring systems used include fishmouth sprung front edge units and coil springs.

Serpentine or sinuous springs are fixed to the seat, back and arm sections of the frame, front to back, and securely fixed via various types of metal fixings or clips. Put simply, there should be at least five springs for each seat, dependant on the length. The frame fixing clips should be securely attached and someone sitting on the sofa or chair should not be able to feel any sharp edges through the upholstery. The suspension system provides flexible support for the seat, back and arms and is normally covered, which helps to ensure the user does not easily feel the clips or springs.

Alternately, rubber or fabric elasticated webbing can be used which provides a flexible support system for the sofa or chair. There must be a sufficient number of webs to maintain the support system. The webbing system may be interlaced across the front to back webs to give additional support.

The suspension is the major support system and must be capable of withstanding the constant initial impact of someone sitting down during the life of the furniture. Some sprung seat platforms incorporate a flexible front edge for improved comfort and reduced cushion wear.

Avoid anything that creaks or squeaks.