We give you a two year warranty on structural and workmanship. The only thing not covered is natural characteristics of the wood.  Pressure treated lumber may warp, crack, split and have unusual shrinkage. It is our policy to do right by the homeowners and if there is only one board that goes bad we will replace at our cost.  More than one and we cover labor costs. If you have a composite deck, most composites have manufacturers warranties that cover from 10 to 25 years.