Changes in this edition include:Common walls separating townhouses must now be rated for 2 hours when an automatic fire sprinkler system is not installed.Remodeling of an existing basement does not trigger the emergency escape and rescue opening requirements unless a new bedroom is created.Ramps that do not serve the required egress door are not permitted to have a slope not greater than 1 unit vertical in 8 units horizontal.Carbon monoxide alarms now require connection to the house wiring system with battery backup. A carbon monoxide alarm is required in bedrooms where there is a fuel-fired appliance in the bedroom or adjoining bathroom.Revised lumber capacities have changed the span lengths for floor joists, ceiling joists and rafters in the prescriptive tables of the IRC.New sections and tables provide prescriptive methods for posts, beams, joists and connections in deck construction.The girder and header span tables of Chapter 5 have been moved into Chapter 6. Multi-ply and single header tables are combined. A new section describing rimn board headers is added.