The decorative lintels were made of five beams of oak wood The bottom beam was wider than the width of the Ulam Entrance by two cubits - a cubit on either side - so that its length was twenty two cubits. The beam above it was bigger than this bottom beam by two cubits, and each ascending beam was in turn bigger than the previous one by two cubits. The top beam was thus thirty cubits. * (Source: Midot 3:7). 
The Entrance Curtain
Contents:   Part I,    Part II,    Part III,    Part IV,    Part V,    Part VI,    Part VII