Thermal requirements for Walls, Attics/Ceilings, Floors above unconditioned spaces, foundation walls, and slabs are provided in terms of Effective Thermal Resistance which considers the thermal bridging components in a wall as well as the insulation.

Effective RSI considers:

• studs, furrings, blocking, joists
• sheathing, drywall finish
• sill plates, bottom plates, top plates
• lintels, headers

Effective RSI does not consider:

• Pipes, ducts, through-wall vented equipment, shelf angles, anchor ties, etc.
• Balcony and canopy slabs, beams, columns
  • as long as insulation is tight against it
  • the total area of all of these penetrations is a maximum of 2% of the wall area.