The deck will be raised 11” (279mm) above the top of your joists. This is to allow for a full depth of attic insulation up to 13.5” (350mm), measured from the floor of the attic plus an air gap above the insulation and below the boards. This essential air gap is there to allow air to flow over the insulation, thereby taking away any humidity which might otherwise condense on the underside of the boards and cause damp.
Note that this height, including the air gap, will allow you to achieve an R-49 depth of insulation, using standard insulation products, suitable for most states in the USA. Consult this guide to see which insulation depth is recommended for your area. If you wish to raise the deck even higher, then we recommend using one row of timber joists beneath the StoreFloor components