What is Blockwork Marking ?
Blockwork marking is the process of transferring the wall layout from the approved drawings onto the actual floor/slab at site before starting block masonry work.
In simple terms:
Block work marking tells the mason exactly where the block wall has to be constructed.
Tools and Equipments used for Blockwork Marking:
| Tool / Equipment | Purpose |
|---|---|
| Measuring tape | Checking wall lengths, offsets, openings and dimensions |
| Chalk line / snap line | Marking straight wall lines on the slab |
| Chalk powder / marking powder | Creating visible reference lines |
| Marker / paint marker | Identifying wall lines, openings and reference points |
| Steel scale | Checking small dimensions and offsets |
| Try square | Checking 90° corners and small layouts |
| Spirit level | Checking local horizontal/vertical alignment |
| Laser distance meter | Quick and accurate distance measurements |
| Laser level | Transferring horizontal levels and reference lines |
| Auto level | Establishing and checking required elevations |
| Total station | Accurate setting-out of coordinates, gridlines and wall locations |
| Plumb bob | Transferring vertical reference points where required |
| String line | Maintaining straight reference/alignment lines |
| Wooden/metal pegs or pins | Establishing temporary reference points |
| Hammer | Fixing pins/pegs where required |
| PPE | Safety during marking and site activities |
Procedure for Blockwork Marking :
- Transfer the 1m Mark to all the columns along which block masonry has to be done
- An Aluminum Straight edge of length not less than 2m is marked at every at 200mm(190mmblock thickness + 10mm mortar thickness), Starting from one edge, up to 2m.
- Wherever block work has to be done, the mark on the straight edge corresponding to a height of 1m from the bottom is coincided with the 1m mark, which has been transferred onto the columns.
- Tie the String line from the column to column at whichever course that has to be constructed along alignment of the wall as per drawing.
- This will ensure perfect horizontally of each course of block masonry and also control the mortar joint thickness.
- Ensure that the locations of openings like windows, doors and ventilators are known.
- In between the sill level and the bottom of the beam has to be measured.
- Calculate the number of full blocks and the mortar joints that can be accommodated within this height (as the mortar joint thickness and the block height is known).
- There is a possibility of a gap occurring between the beam bottom and the topmost full block courses tht can be constructed.
- The height of this gap (adjuster coarse height) is marked at the lintel level or Above the sill level. Further marking is continued as before up to the beam
- It is preferrable to start a marking coarse from the peripheral walls and then continue marking the inner walls an of Apartments.
Inspection Method for Blockwork Marking :
Visual Inspection
Check:
- Visibility of marking
- Continuity of lines
- Wall intersections
- Reference points
- Opening locations
- Clarity of identification
Tape Measurement
Use a calibrated measuring tape to verify:
- Wall length
- Opening width
- Opening location
- Offsets
- Wall thickness
Measurements should be taken from established reference points rather than from random nearby walls.
Laser Level
A laser level can be used to transfer or verify:
- Horizontal reference
- Wall alignment
- Level references
- Opening levels
Auto Level
An auto level may be used where accurate elevation transfer is required.
Typical applications include:
- Sill level
- Lintel level
- Floor reference
- 1 m level
- Other specified elevations
Total Station
For large buildings or projects requiring higher setting-out control, a total station may be used to establish:
- Gridlines
- Wall coordinates
- Column references
- Major offsets
- Building control points
Cross-Check With Drawings
Finally, compare the physical marking with the latest approved drawing.
This is one of the most important steps.
A dimension may be physically measured correctly but still be wrong if the wrong drawing revision was used.
