The Big Wood App is designed to assist carpenters, building inspectors, architects and more to determine whether a selected timber type is the right size for the span given, and is also capable of providing a list of the timber to use for a specific span. The version currently supports Rafters, Ceiling Joists and Underpurlins, however the plan is to add more elements later on. Also the app only supports N1/N2 Wind Speeds at this stage, however if enough requests are made we will most certainly look at expanding this range in the future. All values taken are from AS 1684.