SOISU
Comfort & Technical Sofa Guide
What is foam density in sofas — 40D vs 46D explained?
Foam density in sofas is measured in kg/m³ (kilograms per cubic metre) and indicates how much material is packed into the foam — it directly affects durability and longevity. 32D foam (low density) flattens within 2–3 years of daily use. 40D foam (medium density) is acceptable for occasional use but shows compression within 5–7 years. 46D foam (high density) retains its shape for 12–15+ years under daily family use and is the industry standard for quality sofas. SOISU's Italian sofas use 46D and above foam cores, which is why they maintain their shape and comfort for decades rather than years. When buying a sofa in India, always ask for the foam density specification — any brand unwilling to state this should be treated with caution.
What is the difference between webbing and spring sofa construction?
Webbing and springs are the two main methods used to support the seat of a sofa. Webbing (elastic or jute straps interlaced across the frame) is a lower-cost construction that works acceptably for light use but sags under daily heavy use within 5–7 years. Spring systems — particularly eight-way hand-tied coil springs — individually support each part of the seat, distribute weight evenly, and maintain their tension for 15–25 years. Eight-way hand-tied springs are the gold standard in quality sofa construction and are the method used in Italian luxury manufacturing. SOISU's sofas are built on hand-tied spring systems, which is one of the key reasons they outlast most Indian-manufactured alternatives by many years.
Which sofa is best for back pain?
The best sofa for back pain has a seat height between 45–50 cm (so your feet rest flat on the floor with knees at 90°), a seat depth of 55–60 cm (deep enough to support your thighs without forcing you to slouch), firm lumbar support in the lower backrest, and high-density foam that doesn't sink excessively. Recliners are an excellent choice for back pain sufferers — a reclined position reduces spinal compression significantly compared to sitting upright on a standard sofa. Avoid very deep, soft sofas where you sink in and cannot maintain a natural spinal curve. SOISU's ergonomic sofa and recliner range is designed with these principles in mind. Our design team can advise you based on your specific requirements at the Prabhadevi showroom.
What is the ideal seat depth for a sofa?
The ideal seat depth for a sofa depends on how you use it. For upright sitting — working, dining, or socialising — a seat depth of 55–60 cm works for most adults, allowing you to sit with your back supported and feet flat on the floor. For lounging and watching television, a deeper seat of 65–75 cm is more comfortable as it allows you to recline into the backrest. The most common mistake when buying a sofa in India is choosing a sofa that looks good in the showroom but has the wrong seat depth for your height. SOISU recommends sitting in each sofa for at least 10 minutes during your showroom visit — comfort only becomes apparent after the first 5 minutes.
What makes a sofa ergonomic?
An ergonomic sofa supports your body's natural posture — specifically your lumbar curve, thigh length, and shoulder width — without you having to make conscious adjustments. The key ergonomic features are: seat height that allows feet to rest flat (typically 42–48 cm from floor), seat depth that supports the full length of your thighs, lumbar support in the lower third of the backrest, armrest height that lets shoulders rest naturally (not hunched or dropped), and foam density that provides firm support without feeling hard. Italian furniture manufacturers have historically led ergonomic sofa design because their products are built to last 20+ years and therefore must perform comfortably across that entire lifespan — unlike lower-cost alternatives designed for 3–5 year replacement cycles.
Which sofa is best for working from home and long sitting hours?
For working professionals spending 6–10 hours on a sofa, an ergonomic sofa with lumbar support, medium seat depth (58–62 cm), and firm high-density foam is the priority. A recliner with multiple lock positions is ideal — you can shift between upright for focused work and reclined for calls or reading. Avoid very deep, soft sofas that cause you to slouch, as this creates chronic lower back strain. A sofa with a straight, supportive backrest rather than a lounged-back angle works better for work posture. SOISU's recliner collection, available at our Prabhadevi showroom, includes models with multiple ergonomic positions suitable for extended daily use by working professionals across Mumbai