Measurement of Masonry Brick Works in Construction including Deductions
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Measurement of masonry works in construction is required for calculation of quantities of materials in masonry and to measure completed work. Masonry works are those where cement and fine aggregates without any coarse aggregates are used for construction purpose.
Masonry works are such as brick masonry, concrete block, stone or rubble masonry are generally measured in volume, but are also measured in terms of area where the thickness of masonry is limited to single brick or single block. Tiling is measured in area.
While measuring the quantities of masonry work, the wastage of materials such as bricks, cement or sand is not taken into account. Also, the types and classes of bricks, blocks or tiles are not considering while measuring the quantity of work. This is taken care in pricing of the different masonry works. Each type of masonry works are measured separately into categories to calculate exact cost of construction based on its price.
Rules for Measurement of Masonry Works:
Following are the general rules for measuring masonry works:
1. Masonry is measured as “net in place” with deductions for openings such as doors, windows, ventilation etc.
2. Different shapes of masonry units are measured separately such rectangular, circular etc.
3. Masonry at different heights are measured separately because masonry at higher elevation from ground may require scaffolding and hoisting.
4. Masonry work is measured separately in the different categories such as:
b) Backing to facings
c) Walls and partitions
d) Furring to walls
e) Fire protection
5. Masonry work which requires cleaning of surface are measured in area such as square meter or square feet.
6. Any special treatment to masonry surfaces are measured in area such as square feet or square meter, with the count of number of coats applied.
7. Any joints in masonry structure such as expansion joints or control joints are measured in length such as meter or feet with description of type of joint. Also the type of joint filler material for the joint used is indicated in description.
8. For different types of mortar, or mortar with different types of admixtures are measured separately. These are measured in volume such as cubic meter or cubic feet.
9. If any reinforcement is used in masonry, then it is measured separately.
10. Extra items in masonry construction such as anchor bolts, sleeves, brackets, and similar items that are built into masonry are described in the measurement and measured separately.
11. Enumerate weep holes where they are required to be formed using plastic inserts and such like.
12. Measure rigid insulation to masonry work in square feet or square meters, describing the type and thickness of material.
Measurement of Brick Masonry
For measurement of brick masonry, general rules specified above are used along with following points:
Brick masonry is measured in volume for thickness more than single bricks. For masonry with single bricks, it is measured in square meters.
Facing bricks are measured separately.
Different types or class of brick masonry are measured separately.
Measurement of Concrete Block Masonry
Concrete block masonry are measured as general rules described above along with following points:
Different types of concrete block masonry such as type and size of concrete blocks are measured separately.
Special units required at corners, jambs, heads, sills, and other similar locations are measured separately.
Measure concrete to core fills and bond beams in cubic feet or cubic meters, stating the strength and type of concrete to be used. These are measured separately for different types of concrete block based on strength.
Measure in linear feet or meters reinforcing steel to core fills and bond beams, stating the size and type of rebar to be used.
Deduction for Openings and Bearings in Masonry Works Measurements
No deduction is made for following:
(1) Opening each up to 1000sq cm 0.1 square meter
(2) Ends of beams, post, rafters, etc. up to 500 sq.cm or 0.05 sq.m in section.
(3) Bed plate, wall plate, bearing of balcony (chajja) and the like up to 10 cm depth. bearing of floor and roof slabs are not deducted from masonry.
For other openings deduction are made in following manner:
Deductions for Rectangular Opening:
Full deduction is made for rectangular openings in masonry walls
Deductions = L x H x thickness of wall
Deductions for Reinforced Concrete and Reinforced Brickwork:
Reinforced concrete and reinforced brickwork may be in roof or floor slab, in beam lintel, column, foundation etc and the quantities are calculated in cubic meter. Length, breadth and thickness are taken correctly from the plan, elevation and section or from other detailed drawings.
The quantities are calculated in cubic meter exclusive of steel reinforcement and its bending but inclusive of centering and shuttering and fixing and binding reinforcement in position. The reinforcement including its bending is taken up separately under steel work in as per weight.
For this purpose, 0.6% to 1% (usually 1%) of R.C.C. or reinforced brickwork by volume may be taken for steel if other details are not available. The volume of steel is not required to deducted from R.C.C. or reinforced brick work.
Reinforced concrete and reinforced brickwork may also be estimated inclusive of steel and centering and shuttering for the complete work, if specified. Centering and shuttering are usually included in the R.C.C or R.B. work but may also be taken separately as per square meter of surface in contact with concrete.
Deductions for Flooring and Roofing Works:
The base line concrete and floor finishing of cement concrete or stone or marble or mosaic etc. are usually taken as one job or one item and the quantity is calculated in square meter multiplying the length by the breadth.
The length and breadth are measured as inside dimensions from wall to wall of superstructure. both the work of base concrete and floor finishing are paid under one item.
Supporting structure is taken separately in cubic meter and the lime concrete terracing is computed in square meter with thickness specified under a separate item including surface rendering smooth. The compacted thickness of lime concrete terracing is 7.5 cm to 12 cm average. Lime concrete terracing may also be calculated in cubic meter with average thickness.
Plastering usually 12mm thick is calculated in square meter. for wall the measurement are taken for whole face of the wall for both side as solid, and deducting for opening are made in following manner.
(1) No deduction is made for the end of beams, posts, rafters etc.
(2) For small opening up to 0.5 square meter no deduction is made, and at the time no additions are made for jambs, soffits and sills of these opening.
(3) For opening exceeding 0.5 square meter but not exceeding 3 square meter deduction is made for one side and other face is allowed for jambs soffits and sills which are not taken into account separately
(4) For opening above 3 square meter deduction is made for both faces of the opening and the jambs, soffits and sills are into account and added.
Pointing in wall calculated in square meter for whole surface and deduction similar to plastering is made.
Ornamental and large cornice is measured in running meter or running foots for the complete work which includes masonry, plastering, moldings etc. and paid for in running meter.
Similarly, string course, corbelling, coping etc are measured and paid for in running meters for the complete work.
Pillars are taken separately in cubic meter foe their net volume and quantities are calculated.
Wooden beams, posts, wooden roof trusses, doorpost etc. come under this items and the quantities are computed in cubic meter. The dimension of finished work shall be taken.
This computed weight in kg or quintal and the quantities are calculated correctly by multiplying the weights per running meters by length. the weight per running meter can be obtained from the steel section book. For steel joint the length is equal to the clear span plus two bearing the bearing may taken third forth thickness of wall or 20 to30 cm.
White Wash or Color Washing or Distempering:
The quantities are computed in square meter and are usually same as for plastering. The inside is usually white washed or distempered and this item will be same as for outside plaster. These item need not be calculated separately but simply written as same as for outside plaster and inside plaster.