General Instructions for Laying Concrete Hollow Block:

  • Unlike bricks, the concrete blocks should always be kept dry whilst forming the wall.
  • The first layer should be laid by placing the blocks on C.C. roof or plain surface with addition of mortar.
  • The masons should be instructed to hold a gauge when laying the blocks to prevent the mortar from filling the blank space.
  • 1”-1.5” blank space should be kept under the beam or the roof, which will later be filled with brick chips during plastering.
  • Should keep 1.5” space from the wall before laying the blocks which will be casted with brick chips during plastering after 5 to 6 days.
  • Can construct a wall with 4 layers of 90mm blocks, 5 layers of 100mm blocks & 6 layers of 140mm blocks in one day.
  • Should lay the blocks with conventional mortar from the very next day in general process, but before that, the wall should be cured properly with water. Should always keep in mind that, a block wall should be cured at least for 10 days.
  • Use a #3 bar(10mm bar) inside the hollow space of door or window from floor to lintel level and fill the hollow spaces of the block by grouting (1:2:2).
  • If a wall length is more than 10 feet then the middle blank space should be filled with a #3 bar from the floor level to lintel level and then cast the space with grout.
  • Concrete ratio of 1:2:4 and rod should be casted as per instructed lintel design.
  • At the end of day’s work cover the working area, with polythene during the rainy season.
  • Dry out the wall before plaster work.
  • Outer wall should have a plaster of thickness ¾” and inner wall should have a ½” plaster on both sides. Mixing ratio of plaster and casting should be 1:5. Should cure the space with water for at least 10 days after plastering.
  • Should measure the wall length before laying the blocks. Size of the blocks should be maintained to lay the blocks. The joint of each block should be ½”, hence breaking or cutting any block won’t be necessary.
  • If the measurement of the block is not equal on both the sides or less then adjustment can be done during laying the blocks. The height of the root should be measured in the same manner before laying the blocks. If a blank space of 2”-3” is seen under the roof, then fill the gap with brick pieces.