I have two of these.  One in my back yard for storing ride on mower,  garden tools etc. Have had this one for about seven years.  Anchored to wooden floor. Just started to rip along the centre line.  Tarped for the winter.  The second one i have had for about five years and houses my van in the winter.   Expanding bolts drilled into the ashphalt have kept it secured.  Both have withstood high winds and heavy snow.   Starting to rip along the lower part of the roof line.   Important to remove heavy drifts of snow with a snow rake.   Have to replace both in the Spring, but not happy with the cost of replacement covers compared with the cost of the complete package