Concrete and block/brick junction treatment before plastering

nishead4 Masonry December 25, 2017 | 4

The G I mesh is fixed at the block work and concrete structure junction to avoid formation of cracks during temperature variation due to difference in thermal expansion of these materials.
Due to different coefficients of thermal expansion for Concrete and block masonry, cracks may develop in the plaster at the junctions.
Galvanized Iron mesh rolls of 200mm width is fixed to increase the tensile strength of plastering to reduce the cracks.

G I mesh

Galvanized Iron mesh rolls are available in different sizes like 100mm, 150mm, 200mm. we would prefer 200 mm width for this purpose.

Locations:

Junctions between wall and concrete column(200mm mesh)
Junctions between wall and concrete beam(200mm mesh)
The chasing done on the walls for electrical and plumbing line works.(100mm or 150mm mesh)

Tools required

Step by step procedure

The surface on which mesh has to be fixed should be thoroughly cleaned for any dead mortar or any other foreign particles.
Hacking of the concrete surface should be completed.
Bull fixing should be completed.
The gap if any between the column or beam bottom and the block masonry should be well packed with masonry mortar.
Mesh is cut to the required size and kept ready for fixing.
Marking is done on the wall at a distance of 300mm c/c.
Hole is drilled as per marking done.
Rawal plug or wooden pieces are fixed in the holes.
The mesh should be 200mm in width so that the mesh can cover 100mm on either side of the junction.
The GI mesh is then fixed rigidly over the junction using nails and square washers.
Once the mesh is fixed over the junction it is plastered/packed with rich cement mortar to a suitable thickness such that a minimum of 6 to 8mm plastering thickness.
The surface is made rough when the mortar is wet, so that there is a good bonding surface internal plastering work.
Finally curing should be ensured at least 2 to 3 days before starting regular plastering