Ledger board system

A ledger board for use in constructing a structural extension on an existing structure, the ledger board comprising:

• a monolithic body extending along a longitudinal axis, the monolithic body being attachable to one or more structural members of the existing structure, wherein the monolithic body includes an inner attachment surface for engaging the existing structure and has a cross-sectional configuration defining:
• an upper flashing portion having an outer surface;
• an upwardly open gutter conduit extending along the longitudinal axis below the flashing portion;
• an upwardly facing support surface extending along the longitudinal axis above the gutter conduit;
• an outwardly facing mounting surface extending along the longitudinal axis below the support surface, wherein the mounting surface is an outermost surface of the ledger board and is a vertical surface;
• at least one fastener channel extending along the longitudinal axis below the support surface, wherein the at least one fastener channel is open through the mounting surface;
• and
• a downwardly open siding groove extending along the longitudinal axis;
• wherein the cross-sectional configuration of the monolithic body further defines a fastener duct extending along the longitudinal axis underneath the upwardly facing support surface.