Birds Mouth Cut Calculator

Calculate Birds Mouth Cut Dimensions

About Birds Mouth Cut

A birds mouth cut is a notch cut into the bottom of a rafter to allow it to sit properly on the wall plate.

Purpose:

  • Provides proper seating on wall plate
  • Distributes load evenly
  • Prevents rafter from sliding
  • Creates clean, professional appearance

Key Measurements:

  • Seat Cut: Horizontal cut depth
  • Heel Cut: Vertical cut depth
  • Cut Angle: Angle of the notch
  • Remaining Depth: Uncut portion

Safety Guidelines:

  • Never cut more than 1/3 of rafter depth
  • Maintain structural integrity
  • Use proper cutting tools
  • Follow local building codes

Common Applications:

• Residential roof construction
• Shed construction
• Gazebo building
• Pergola construction
• Deck construction

Tools Required:

• Circular saw or handsaw
• Speed square
• Pencil for marking
• Measuring tape
• Safety equipment

Proper birds mouth cuts ensure structural stability and professional appearance in roof construction projects.