BISON SHEDS are high-quality, premier grade garden buildings. They are robust sheds and summerhouses, made in Britain using slow-growing Scandinavian trees. The wood has a tight grain, therefore each building is stronger and will last many years. The timber is pressure-treated (Tanalised™) using the next-generation Tanalith-E™ preservative. Tanalised™ products have a very long lifespan, and with minimal maintenance, can easily last 20-25 years. Bison Sheds come with a 15-year preservative warranty against rot, however the colour will change to a natural silvery/grey if they are left untreated*. Bison garden buildings come in several styles: apex and pent storage sheds, beautiful garden studios, and cosy octagonal summerhouses. Each model comes in various sizes. Very heavy framing is used, therefore every Bison building has a strong structure. The 16mm thick walls, floor, and roof are much thicker than most other UK garden buildings. Interlocking boards (tongue and groove) are used in all Bison Sheds. NO chipboard, OSB or other low-grade timber is used in Bison Sheds™. Joinery-made doors and window frames are of high quality, and are morticed & tenoned for strength and a long life. Upgrades are available for many of these buildings, and options include toughened glass, double-glazing, and flower boxes for the windows. Door upgrades are also available, such as wider doors, double doors, stable doors. Security, options like window grills, security bars, and security hinges can be purchased too. *Tanalised™ garden buildings are guaranteed against rotting. However we highly recommend coating the outside with a waterproof treatment such as Restol Wood Oil, or Protek Stable Coat. This will prevent dampness inside your building.