Work Procedure for Size Stone Masonry

Work Procedure for Size Stone Masonry
  1. Follow the latest “Good for Construction” drawings duly signed by the architect.
  1. Check for any variations/deviations from the approved architectural and services drawings.
  1. Use silt free (less than 5%) medium gritty clean sand for mortar.
  1. Approved grade cement less than 1 month old should be used.
  1. Ensure that all required tools, accessories and materials are available at the place of work.
  1. The stones should not be soaked in water prior to use. However, a light moistening with water may be done on the top and sides of the stones just before placing of stones in courses, so as to avoid absorption of water from the cement mortar and to ensure development of bond with the mortar.
  2. Before commencing masonry work, the line out shall be carried out for the entire area using a steel tape. The dimensions shall be checked with respect to Architect’s drawings and any discrepancy shall be brought to the notice of Architect.
  3. The stone masonry shall be preferably laid in composite mortar with mix ratio as mentioned in specification and drawing.
  4. The mortar proportions shall be either 1:4 or 1:6. The mortar when mixed shall have a slump of 75mm.
  5. The thickness of mortar joints shall be 10 mm both horizontally and vertically. The mortar shall be spread over the entire top surface of the stone; (over the front and rear shells). Mortar shall not be spread so much ahead of the actual laying to avoid formation of a weak bond. The mortar shall be raked out from the joints with a trowel of each course and is laid to a depth of 10mm to 12 mm, so as to ensure good bond for the plaster.
  6. The height of wall to be done in a day’s work shall be restricted to 1 meter.
  7. The first course of masonry shall be laid with great care, making sure that it is properly aligned, levelled and plumbed, as this will assist the mason in laying succeeding courses to obtain a straight and vertical wall.
  8. The stones for this course shall first be laid dry, (that is without mortar) along a string tightly stretched between properly located corner stones of the wall in order to determine the correct position of the stones and their spacing. When the stones are set in proper position, the two corner stones shall be removed, a full mortar bed spread and these stones laid back in place truly level and plumb. The string shall then be stretched rightly along the faces of the two corner blocks and the faces of the inter-mediate ones adjusted to coincide with the line.
  9. Thereafter each stone shall be removed and re-laid over a bed of mortar. After every three or four blocks have been laid, their correct alignment, level and verticality shall be carefully checked.
  10. As each course is laid at the end / corner, it shall be checked for alignment and level or straight – edge to make certain that the faces of the stone are all in the same plane. This precaution is necessary to ensure truly straight and vertical walls.
  11. When filling in the wall between the ends, a mason’s line shall be stretched from end to end for each course and the top outside edge of each stone shall be laid to this line. The mortar joints in the masonry shall be cured for seven days. The walls shall only be lightly moistened during curing.
After 7 days of curing of mortar joints drive a nail into the joint to test the strength of joints at random. Also look for colour variation in the mortar joints to identify problem areas.

Waterproofing plaster in case of retaining walls should be done for all external surfaces. Bitumen touch-on and Thermocol protection is done before backfilling in layers and compacting.

Required tools must be available at site to ensure correct work. Basic tools of the masonry gang are:

  1. Trowels
  2. Line dori
  3. Sand Sieve
  4. Tube levels
  5. Plumb bobs
  6. Measurement Tape
  7. Spirit levels 1-2m
  8. Aluminium straight edge
  9. Right angle
  10. Chipping Tools
  11. Masons trowels
  12. Masons hammer
  13. Levelling threads
  14. Masons brushes and buckets
  15. Mortar boxes
  1. The first course in masonry is the most important one.
  1. Check if the erected wall is perfect – free from cracks.
  1. Using the tape measure, ensure the diagonals are equal.
  1. Check up if the corners are at right angles using the right angle template.
  1. Check of joint thickness and strength after 7 days (nail test)
  1. Check if proper storm water drains have been provided adjacent to peripheral / retaining SSM walls.
  1. Waterproofing all around / along the building and external masonry walls 50cm above and 50cm below ground level.
  1. Plumb bobs
  2. Spirit levels 3m
  3. Right angle
  4. Measuring tape
  5. Related “Good for Construction” drawings
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