Types of bands in masonry structures

Bands (ring beams) in masonry

A band is a continuous horizontal reinforced element (RC, reinforced brick or timber) running around all walls of a building at a given level. It ties walls together so they act as a box, and reduces bending of walls out of plane.

Types of bands (NBC 202 / IS 4326)

1. Plinth band: at plinth level, over the foundation wall. Needed when soil is soft or likely to settle unevenly; it also acts as a damp-proof course base and reduces differential settlement.
2. Lintel band: at lintel level of doors/windows; most important band. It ties walls together and carries lintel loads. Lintels can be merged in this band.
3. Roof band (eaves band): at the top of walls under the roof. Needed where roof is of sloping/flexible type (sheeting, timber, trusses) to anchor the roof.
4. Gable band: a band running along the top of gable-end triangular walls to hold the gable.
5. Sill band (optional): at window sill level, for extra stiffness in tall wall areas.

Details: thickness of RC band at least 75 mm; width equal to wall thickness; concrete M15 or richer; two bars of 8-12 mm diameter depending on the span (about 8 mm for spans up to 5 m, larger for longer spans) with 6 mm stirrups at 150 mm c/c. Corners and junctions must have continuous reinforcement lap, and the band must be continuous around the building.

   ____ roof band ______
  |  []   []   []   | <- lintel band (ring)
  |__|__|__|__|__|__|
  |                  | <- plinth band
  ======== foundation