The structure is the complete frame of your sofa that will give it its shape. It can be made of wood or metal (especially for models offering relaxation functions), but the most resistant are often in solid woods such as pine known for its solidity. A frame generally includes plywood, particle or fiber panels to fill the interior of the framework, whose strength can be considered good from the moment their its thickness exceeds 15mm.
In terms of assembly, stapling remains the most common method because it’s the most reliable, although it is possible to find structures both stapled and glued for even more strength.
If you choose a convertible sofa bed, the opening mechanism should be strong if you plan on using it often. On most models of the convertible sofa bed, there are generally three types of mechanics, each corresponding to a frequency of use envisaged for the sofa:
- Daily use—Unfold the sofa directly, without removing any cushions
- Regular use—Remove the back cushions before unfolding the sofa, but the seat cushions remain attached to the structure
- Occasional use—Remove the back and seat cushions before unfolding the sofa and installing the bed
The sofa’s suspension supports the cushions receiving the pressure, both for the seat and the back of the sofa. This is the element that will provide the sofa with most of its comfort. There can be two types used for the seat, in most cases concealed by canvas.
Intertwined straps—This is made from elastic textile strips and is noted as one of the most comfortable systems. The strips are placed flat but can also be crisscrossed in order to enhance the strength of the seat. It has also been noted that this is the only system that can be used for corner sofas.
Springs—This system has a more durable elasticity. Each spring responds to pressure in an isolated way in order to offer independent comfort. There are a few different types of springs such as the classic spiral spring and the wire suspended flat spring, but certain professionals consider the pocket springs or zig zag springs of the best quality for sofas. As for the backrest suspension, which requires less strength since it receives less pressure, manufacturers often use elastic straps or a fixed support. They often use a panel made from wood fibers.