What is the minimum end bearing for bearing joists and rafters?

What is the minimum end bearing for bearing joists and rafters?

• A. 25 mm
• B. 38 mm
• C. 50 mm
• D. 75 mm

Answer: (B)

End bearing length is how far the end of a joist or rafter sits on a support to transfer its weight into that support. For bearing joists and rafters, a minimum of 38 mm provides enough contact area to carry the load without locally crushing the timber or weakening the end, while still letting you seat the end properly on a wall plate or beam and fasten it effectively. A smaller bearing like 25 mm increases the risk of end crushing or fiber damage under load, while larger bearings (50 mm or 75 mm) aren’t typically required for normal residential framing and would waste material and complicate fits.

End bearing length is how far the end of a joist or rafter sits on a support to transfer its weight into that support. For bearing joists and rafters, a minimum of 38 mm provides enough contact area to carry the load without locally crushing the timber or weakening the end, while still letting you seat the end properly on a wall plate or beam and fasten it effectively. A smaller bearing like 25 mm increases the risk of end crushing or fiber damage under load, while larger bearings (50 mm or 75 mm) aren’t typically required for normal residential framing and would waste material and complicate fits.