Sofa Frames & Springs

Hardwoods (the woods of deciduous trees) are strong, durable and can withstand weight over an extended period of time making these the better choice for wood frame sofas.

Kiln drying, which removes any moisture from the wood to prevent warping and helps the sofa frame retain its shape over time, is a standard industry procedure carried out by all respectable wood suppliers and should be the only acceptable choice for a luxury sofa design.

This type of wood is another industry standard and the most responsible and sustainable approach to wood furniture construction. Producers of FCS-certified woods adhere to the Forest Stewardship Council’s 10 rules which include “maintain[ing] or enhanc[ing] the social and economic wellbeing of workers” and “maintain[ing], conserv[ing] and/or restor[ing] ecosystem services and environmental values” of their forests as well as striving to “avoid, repair or mitigate negative environmental impacts”.

Popular woods for high-end sofa frames are maple, beech, alder, poplar and ash which means that quality frames will also be quite heavy.

These types of wood can also work well for sofa frames, however, care should be taken to discover the lengths to which the manufacturer has gone to produce the strongest and best quality wood and where this will be used. Sometimes, even in luxury sofa manufacturing, composite woods or softwoods are used for sofa frames in non-stress areas. This is acceptable if affixed properly because these areas do not take weight.

Used on their own, softwoods and composite woods will be unable to provide the correct sofa support to the sitter on their own and will likely splinter or buckle within a few years. Metal frame sofas also exist but are typically not as comfortable as a hardwood frame.

The eight-way hand-tied method - the most traditional coil spring suspension - results in one of the most comfortable sofas. Also known as a coil sprung system, it consists of individual hourglass-shaped couch springs of varying thicknesses being individually affixed to the webbed seat base. This is done by hand and the knots are tied in an eight-way configuration - front to back, left to right and diagonally in both directions.

Fixing the coil springs individually provides the most tailored support because each can respond, independently, to differing weight pressures. This offers support and distributes weight correctly.

Also known as sinuous springs, S-springs or zig zag springs, serpentine springs are flat and feature repeating, zig zag curves. These wires are attached to the sofa deck from front to back.

These springs come in various thicknesses depending on the desirable comfort level, i.e. higher and firmer or lower and softer, and straight cross wires are placed at right angles to the serpentine springs to provide further support. Springs with tighter curves and with more turns provide more strength as do plentiful wires placed close enough together so that the sofa has an even and supportive seat surface.

Pocket sprung units are made up of multiple coils, individually wrapped in a lightweight fabric and bound together at the top and bottom with metal rings. These pocket spring systems are not as desirable as other spring systems because they are usually made of inferior materials and can weaken and wear out. They are known for being uncomfortable and can be noisy too. Pocket spring units would never be recommended for high-end upholstery.

Buyer beware - some sofa manufacturers will claim that their sofas are eight-way tied because they are spring-based when, in reality, they are pocket sprung sofas.

Upholstery webbing is the simplest form of sofa deck and consists solely of a webbed base without any additional spring system support which means that is doesn't provide responsive support. Although rarer, web suspension works well in some instances and was used prevalently in Mid-century design, for example. Webbing alone is a popular option for slimmed down modern sofas because it doesn’t require the same depth as spring systems.

If used alone, it should be of a high enough quality to ensure resiliency and fitted correctly so as to not cut through any surrounding foam.