I purchased this shed along with the extension kit last summer. I had no difficulties assembling/ installing and the shed stood up well until a heavy snowfall late in the winter at which time the roof collapsed. All trusses and roof panels were bent beyond repair. Warranty department was quick to replace entire roof asking only that I pay for shipping. Warranty staff were responsive, easy to work with, helpful and polite. They honored the warranty with no questions.  My only criticism is that I  learned of the snow load kit only after the collapse.  Retailer said nothing about this at time of purchase.  I would suggest that retailers, particularly in snow country, be advised of the kit and that they better inform customers of the need.