Tongue & Groove is another superior build quality in sheds and buildings. This allows the panels to slot into each other rather than overlapping and sitting on top of each other. These tend to be mid-range quality, as this build style ensures a more structurally rigid and superior structure. Tongue & Groove elements are also available in Overlap Sheds. You may have an overlap shed, but see than elements such as the floor or roof come in a T&G style.