Things to check for when buying a shed or storage building:
What size are the studs and what is the measurement between studs? Most of the strength of your building is in stud dimensions and spacing between studs. A strong shed wall will have 2”x4” studs with a 16" on center spacing. Exterior fasteners should be dip galvanized and of adequate length.
What is the exterior made of? How much maintenance will it require? A good building will have a maintenance-friendly exterior. Check a painted building for quality paint. Quality paints can give you many years of maintenance-free enjoyment with very minimal effort in the upkeep of the structure. Overall, a painted building should hold up as well as a steel siding, and much better than a pressure-treated and stained exterior.
What is on the roof? Good quality steel or Architectural shingles can give you from 45 years to Lifetime manufacturer warranties.
Check the trim and floor: A good floor will have ¾” sheeting for strength and longevity. The floor joists spacing should be 16" or closer for strength.
¾” trim board is a standard thickness for house trim and shows quality on shed structures.
What is the sub-frame made of? A pressure-treated sub-frame is a must for a shed due to the constant ground contact of the structure.
A major weak point on a garage style structure can be "bracing" around garage doors. If there is inadequate framing or bracing on the garage door wall, the building may start to lean in high wind areas.
Check the doors. How do they close? Do they feel heavy and solid? A door that is lined on the inside stiffens the door and prevents warping. Remember, the door and hardware are major components of your building and should last for the lifetime of the shed.