UK Universal Beam sections and Eurocode 3
UK building control requires structural steel beams (RSJs / Universal Beams) to satisfy both ultimate limit state (bending moment and shear) and serviceability limit state (deflection).
Common domestic sizes include 178x102x19 UB, 203x133x25 UB, 254x102x22 UB, and 254x146x31 UB in grade S275 or S355 steel.
Worked example: 4-metre load-bearing wall opening
A ground-floor wall removal spanning 4.0m carries 12 kN/m combined dead and live load.
A 203x133x25 UB beam provides a moment resistance well above 24 kN·m with deflection of 6.7 mm, complying with Building Regulations Part A.
UK beam sizing inputs
Beam Profile
Select standard British Universal Beam (UB) serial size.
CALCULATOR QUESTIONS
UK Universal Beam (UB) deflection calculator questions
What size steel beam do I need for a 4 metre opening?
For typical domestic openings carrying ceiling and roof loads, a 203x133x25 UB or 203x102x23 UB is commonly specified, subject to engineering calculation.
What does RSJ stand for?
RSJ stands for Rolled Steel Joist, the historic term now replaced by Universal Beams (UB) and Universal Columns (UC) in modern UK construction.