Wood, springs padding, dowels, staples, nails, nylon webbing, and foam are the materials used in upholstery frame construction. The inherent quality of the finished sofa, loveseat, chair, sectional, or ottoman is based on, obviously, the quality of its parts and method of construction. High quality framing is made the old fashioned way, by hand, and the starting ingredient in frame construction is the wood. Only kiln dried hardwood joined by dowels, glued, and blocked for durable structural integrity, is used in upholstered products sold at Model Interiors. The seating spring system in is either a sinuous coil, helical coil drop-in unit, or an eight -way hand tied spring system (the top end of the market). In eight-way hand tied construction, the helical springs are hand-tied in eight different directions which provide for uniform load distribution, and longer life. Another durable seating system, the most critical element in frame construction, is what is termed a drop-in coil unit.
This is a pre-fabricated coiled spring unit that is made into a single piece tied together with wire of varying gauges, and then dropped into the seating area of the sofa, loveseat, chair, or sectional frame. This is a faster and less expensive construction method than eight-way hand tying, but since it uses vertical helical coils, it offers some of the same quality features. The sinuous coil seat construction method is designed with regularly spaced sinuos wire attached to the front and back frame of the upholstered furniture, and then each unit of wire spring is tied together horizontally. This is the fastest and cheapest method of seat construction.