​The 2012 Residential Building Code became effective March 1, 2012.

Here are some of the new code sections or changes to the Residential Building Code:
 
R302 Fire-Resistant Construction
Code sections in other parts of the code related to fire-resistant construction have now been consolidated into this section.
  
Table R302.1 Exterior Walls
The minimum fire separation distance not requiring fire-rated walls is now 5 or more feet.
  
R302.2 Townhouses
If an automatic residential fire sprinkler is installed, a common, 1-hour fire-resistance-rated wall is permitted (a 1-hour reduction).
  
Table R-302.6 Dwelling/Garage Separation
Not less than 5/8” Type X gypsum board on the garage ceiling to separate from habitable rooms above.
  
R302.7 Under-Stair Protection
Enclosed accessible space under stairs shall have walls, under-stair surface and any soffits protected with ½” gypsum board.
  
R302.13 Combustible Insulation Clearance
Combustible insulation shall be separated a minimum of 3 inches from recessed lighting, fan motors and other heat-producing devices.
  
Figure 307.1 Minimum Ceiling Height at Bathroom Fixtures
This table specifies where the required minimum 6’8” headroom measurements are to be taken and the minimum clearances in front of the fixtures.
  
R310.1 Emergency Escape and Rescue Required
The 2012 code requires that ALL basements, habitable attics and all sleeping rooms must have an emergency escape and rescue opening. There is an exception for basements used for mechanical equipment and not exceeding 200 square feet.
  
R312.2 Height
A requirement has been added that requires the height of a guard to be measured from the top of any fixed seating immediately adjacent to the rail.
  
R312.3 Opening Limitations
Where the 2009 code allowed passage of up to a 6” sphere in intermediate rails or ornamental guards, the 2012 code has reduced that to a 4” sphere. The 2009 exceptions for side stairs and the triangular openings created by a tread and riser are still applicable.
  
Table R403 Minimum Width of Concrete or Masonry Footings
There have been some reductions in the minimum footing sizes.
  
Figure R403.3(1) Concrete and Masonry Foundation Details
Note 1 has been revised to read: Foundations shall extend not less than 12 inches below finished grade and in no case less than the frost line depth.
  
R403.4.1 Crushed Stone Footings
The 2012 code includes prescriptive footings (crushed stone or concrete) that may be used for precast concrete foundations.
  
R404.5 Precast Concrete Foundation Walls
The 2012 code includes prescriptive requirements for precast concrete foundation walls.
  
R408.2 Ground Vapor Retarder
This section has been revised to remove the requirement for a vapor retarder for all wall-vented crawl spaces. You may reduce your venting requirements to 1/1500 of the under-floor area where the ground surface is treated with an approved vapor retarder installed in accordance with this section.
  
Table R602.3(1a) Fastening Schedule
This is a new table added that includes power-driven fasteners.
  
R602.10 Wall Bracing
This section has been completely rewritten with all new requirements for wall bracing.
  
R612.2 through R612.4 Window Fall Prevention Protection
If any part of the clear opening of the operable portion of a window is located more than 72 inches above the exterior grade, then the lowest part of the clear opening must be at least 24 inches above the floor of the room in which it is located.
 Exceptions: 
1. The window is a fixed unit.
2. The opening does not allow the passage of a 4” diameter sphere.
3. The window is equipped with a fall-prevention device meeting ASTM F 2090.
4. The window is equipped with an approved window opening-limiting device.
  
R807.1 Attic Access
The minimum attic area requiring attic access has changed from 100 square feet to 400 square feet.
  
Chapter 11 Energy Efficiency
This chapter has been completely rewritten.