Residential Building Cost by Thumb Rule (Rate Per Square feet)

RESIDENTIAL RCC BUILDING COST BY THUMB RULE

Thumb rule to calculate the Steel quantity required for Slab, Beams, Footings & Columns:

For Residential buildings 4.5Kgs-4.75Kgs /SFT

For Commercial buildings 5.0Kgs-5.50Kgs/SFT

For more accurate results you can also use BN Datta recommendations:

As per B N Datta, the Steel quantity used in different members of the building can be calculated easily using the following recommendations.

Structural Member Percentage of Steel

Slab: 1% of the total volume of concrete

Beam: 2% of the total volume of concrete

Column: 2.5% of the total volume of concrete

Footings: 0.8% of the total volume of concrete

Example:

Thumb rule to calculate Steel quantity of above slab = Volume of Concrete x Density of Steel x % of Steel of Member

Steel quantity required for above slab = 3 x 7850 x 0.01 = 235Kgs

Thumb rule to calculate the Shuttering area:

Shuttering costs 15-18% of the total construction of the building. 

Shuttering is framed to bring the concrete in Shape. 

The Thumb rule to calculate the shuttering required is 6 times the quantity of concrete or 2.4 times of Plinth area.

Suppose, the concrete quantity is 0.5m3

then the shuttering area required is 0.5 x 6 = 3m2

Components of Shuttering:-

Shuttering Ply, Battens, Nails are components of Shuttering.

Shuttering Ply Quantity calculation:

The shuttering Ply has a length, width & depth of 2.44 x 1.22 x 0.012

The No. of Shuttering Ply sheets = 0.22 times of Shuttering

Suppose, the area of shuttering required = 3m

Then the Shuttering Ply required = 0.22 x 3 = 0.66m2

Battens Quantity Calculation:

Shuttering batten usually have a length & width of 75mm x 40mm.

Batten Quantity = 19.82 x No. of Ply Sheets

if the construction requires 25 Ply sheets, 

the total quantity of Battens are 19.82 x 25 = 495 Battens

Nails & Binding Wire Quantity in Shuttering:

75gms of Nails are used for 1m2 of Shuttering

75gms of Binding wire is consumed for every 1m2 of Shuttering.

Thumb rule for Shuttering oil Quantity:

Shuttering oil is used to de-frame or de-assemble from the concrete easily.

Total required Shuttering oil is = 0.065 x Total Area of Shuttering

(or) For every 15Sqm of shuttering 1 liter of shuttering oil is consumed.

Example :

15m2 is total area of shuttering, then Shuttering oil required = 0.065 x 15 = 0.975 lts

For Accurate Shuttering Area Calculation, You can check here Shuttering area required for slabs, columns, Beams, Footings

Thumb rule for Cement, Sand, Coarse Aggregate Quantity in Different grades of Concrete :

Concrete Mix    Cement Quantity   Coarse Aggregate Quantity  Fine Aggregate Quantity

M5 (1:5:10)           2.82 Bags                        0.98m3                                0.49m3

M7.5(1:4:8)           3.48 Bags                        0.97m3                                0.48m3

M10(1:3:6)            4.50 Bags                        0.90m3                                0.45m3

M15(1:2:4)            6.60 Bags                        0.88m3                                0.44m3

M20(1:1.5:3)        8.40 Bags                        0.84m3                                0.42m3

For Accurate calculation refer to Concrete Mix design for Different grades of concrete

Thumb rule for Cement quantity in Brickwork, Cement Masonry & Plastering work in construction:

Brickwork Thumb rule:

Brickwork for 1Cum                Cement Qty in Cum    Cement Qty in Bags

230 mm Brickwork                           0.876m3                        25.4 Bags

115 mm Brickwork                            0.218m3                        6.32 Bags

Cement Masonry Quantity Thumb Rule:

Cement Masonry Type & Mix                            Cement Qty in Bags       Cement Qty in Kgs

200mm in Cement Masonry work of ratio 1:6        0.124Bags/m2                6.2Kgs/m2

150mm in Cement Masonry work of ratio 1:6        0.093Bags/m2                4.65Kgs/m2

200mm in Cement Masonry work of ratio 1:4        0.206Bags/m2                10.3Kgs/m2

150mm in Cement Masonry work of ratio 1:4        0.144Bags/m2                7.2Kgs/m2

100mm in Cement Masonry work of ratio 1:4        0.103Bags/m2                5.15Kgs/m2

Plastering Quantity Thumb Rule:

Type of Plastering                        Cement Qty in Bags                     Cement Qty in Kgs

Rough Plastering                                0.09Bags/m2                                4.5Kgs/m2

Internal Wall Plastering                        0.09Bags/m2                                4.5Kgs/m2

Duct Plastering                                    0.09Bags/m2                                4.5Kgs/m2

External Wall plastering                        0.175Bags/m2                            8.75Kgs/m2

Stucco Plastering                                0.175Bags/m2                                8.75Kgs/m2

Lathen Plastering                                0.55Bags/m2                                   27.5Kgs/m2

Construction cost estimation heads are:-

Services works – The service works cost varies between Rs 305 – 320 /- per Square feet and about 17 % of total construction cost. 

This construction cost estimation head includes essential services like plumbing, electrical, HVAC, fire fighting, etc. The cost of CP, sanitary, and other fitting are also included under this head.

Finishing works – This includes all finishes work i.e flooring, painting, marble works, woodworks, MS  railing, Gypsum plaster, etc. The cost varies between Rs 420 – 450 per Square foot and about 23 % of the total construction cost.

Civil works – This is the highest construction cost estimation head involved in this construction phase which includes excavation, footings, RCC work, Blockwork, plaster, etc. The cost varies between Rs. 980 – 1000 per Square feet and about 53% of the total project cost.

 

Consultant cost – In this the consultant cost varies between Rs 43 – 45 per Square foot and about 2.5 % of total construction cost. This includes the cost involved for architectural design, structural design, services design, etc.

Site establishment and temporary works – This construction cost estimation head includes the cost for barricades, clearing site, water and electrical charges for construction activities, site office construction, etc. The cost varies between Rs 85 – 90 per Square foot. and about 4.5 % of the total construction cost.

The below table gives a more detailed idea about construction cost estimates for each activity

Sr. No.            Contract Code and Name                    Cost per Sq ft            % of the total cost

(A)                  Consultants

1                    Architectural designing                        21.85                                    1.2

2                    Structural designing                                7.28                                        0.4

3                    Services                                               13.11                                    0.7

7                    Model making                                      1.098                                    0.1

9                    Plot Survey                                          0.13                                      0.0

Total                                                                               43.83                                    2.4

(B) Civil Works

1                    Excavation                                            15.96                                0.9

2                    Anti termite treatment                           0.10                                    0.0

3                    Substructure Waterproofing,                3.96                                    0.2

4                    RCC works, Blockwork, Plaster, 

                      Misc civil works                                        966.76                            52.0

Total                                                                                986.80                            53.1

(C) Finishing Works

1                    Flooring                                                142.01                            7.6

2                    Kitchen Platform with Sink                  21.41                                1.2

3                    Entrance lobby & signage                    9.15                                   0.5

4                    Woodworks                                         67.81                                3.6

5                    Waterproofing                                       12.74                                0.7

6                    Gypsum Plaster                                    36.52                                2.0

7                    P.O.P false ceiling                                6.49                                    0.3

8                    External Painting                                 20.82                                1.1

9                    Internal Painting                                  21.26                                1.1

10                 staircase painting                                 1.91                                    0.1

11                 Lift Shaft Painting                                0.34                                    0.0

12                Duct Painting                                        2.53                                    0.1

13                Ceiling paint                                            7.62                                  0.4

14                Aluminum Window                                46.19                                2.5

17                M.S Railing                                            11.16                                0.6

18                Facade work                                            6.19                                0.3

Total                                                                            419.69                                22.6

(D) Services

1                Plumbing & pumping                            51.57                                    2.8

2                CP Sanitary                                            44.45                                    2.4

3                Fire fighting                                            23.43                                    1.3

4                Electrical                                                76.44                                       4.1

5                Lifts                                                        82.40                                    4.4

6                IBMS                                                     16.33                                     0.9

7                Solar water system                                4.39                                        0.2

8                DG Set                                                    6.59                                        0.4

Total                                                                            305.63                                16.4

Initial Total (A+B+C+D)                                            1755.96                              94.4

Site Establishment                                                        33.01                                1.8

Electrical & water charges 1.5%                                26.33                                    1.4

Contingencies for temporary works                            17.55                                   0.9

EHS budget                                                                  8.77                                    0.5

Construction Cost / Sq ft                                            1859.22                                  100

This Estimate can be changed with respect to site specification, material quality, time, rate of labour, location of the site, etc. 

Team

CBEC India

Top Terrace Waterproofing - Standard Work Procedure

 Top Terrace Waterproofing

Introduction:

This standard operating procedure enumerates the scope of Waterproofing work in toilets to be executed in Tower area as specified in the approved drawings.

Responsibility:  

The respective Tower-in-charge is responsible to execute the work as per procedure.

Safety & protection:

PPEs like safety belts at height, helmets, safety goggles etc. should be used properly. 

Ensure the working area is kept clean for easy access.

Proper illumination to be provided during the work, if required.

Educate the workmen through pep-talk meeting. 

Preparatory works:

Cleaning of slab base and sides of beams shall be carried out as regards all those materials, mortar, oil etc. thoroughly by wire brush and the area shall be washed clean.

PVC sleeves should be removed.

Slab should be filled with water and next day should be inspected for leakages.

If Leakages found, then cracks should be open out by making grove and pressure grouting by socket should be done. After completion of treatment sunken slab should be again recheck for any leakages.

Ensure all plumbing lines are installed on top of slab as per slope specified in approved drawing.

Work Method:

Brick bats should be soaked thoroughly for about 15 minutes prior to their placing.

Cement mortar in 1:4 proportions should be prepared and laid on slab. Mortar mixed shall be used within 1Hour of preparation.

 Pre-soaked brick-bats shall then be laid in straight / radial, by inserting brickbats to a depth of about 15mm by light tamping with the help of mallets. Distance between adjacent layers of brickbats shall not exceed 25mm.

 Application of brick-bats shall proceed from one corner. Thiyya (level pads) for the same shall be given by Site Engineer, considering into account adequate slope towards rain water drain.

Mortar should be filled up to half height of brick bats and it should be cure for minimum 3 days. 

After curing is over, the surface shall be applied with a finishing coat of cement sand mortar in the proportion 1:4 with waterproofing compound (Fosroc Conplast X 421 IC) @ 150ml per bag of cement till top of brick-bats.

 Top coat shall be of neat cement slurry of adequate consistency and shall be done monolithic with topping of brick-bats with slope towards rain water drain.

Finished surface shall then be cured for at least 7 days by ponding and then tested for leakages, if any.

Team 

CBEC India

Kitchen Platform - Standard work Procedure

 Kitchen Platform

Introduction:

This standard operating procedure enumerates the scope of Tiling work to be executed    in Tower area as specified in the approved drawings and at places when instructed by the Tower-in-charge.

Responsibility:

The respective Tower-in-charge is responsible to execute the work as per procedure.

Safety & protection:

PPEs like safety belts at height, helmets, safety goggles and ear plugs etc. should be used properly. 

Ensure the working area is kept clean for easy access.

Proper illumination to be provided during the work, if required.

Educate the workmen through pep-talk meeting. 

 

Preparatory Works:  

Check the height of Platform vertical is as specified in drawing. Vertical top should be in level.

All visible edges of platform granite should be polished before fixing it in place.

Slot the wall 2 in depth at correct height as specified in drawing for inserting platform in wall.

Cutting of Kitchen sink and gas hole should be done as per approved drawing and checking the pluming points on wall.

At wall where the gas cutout in platform comes chase the portion to fix the flexible pipe for gas. Gas hole is to be taken from skirting and through wall take it below platform.

Work Method:

At sink area first fix the secondary marble and then fix the sink as per drawing and plumbing points on wall.

Apply the resin hardener adhesive on top of vertical. And place the platform in position by inserting it by 2 in wall.

Check the top level of platform it should not have any slop.

Fill the wall chase area in mortar of 1:4.

Do fix skirting in place as per drawing.

At gas hole put the flexible pipe in wall with a sample gas pipe inside of it, for insuring the correct curvature of pipe and fill the wall chase portion with cement mortar of 1:4.

Flexible pipe should be then cut at the face of skirting and below platform at the face of wall and sealed properly.

Fix the facia patti (Architrave) as per approved drawing with resin hardener. Coins should be inserted into facia patti and platform to increase its stability.

Apply the approved sealant around sink and platform joint neatly to make it waterproof.

Grout the joints with approved grout and clean the platform.

Do apply light coat of clear oil on granite face for protection.

Post Checks:

Check the gas hole for its operation.

Check the level of platform.

Check for alignment of sink with plumbing points.

Check for any visual defect.

Team

CBEC India

Toilet Waterproofing - Standard Operating Procedure

Toilet Waterproofing

Introduction:

This standard operating procedure enumerates the scope of Waterproofing work in toilets to be executed in Tower area as specified in the approved drawings.

Responsibility:  

The respective Tower-in-charge is responsible to execute the work as per procedure.

Safety & protection:

PPEs like safety belts at height, helmets, safety goggles etc. should be used properly. 

Ensure the working area is kept clean for easy access.

Proper illumination to be provided during the work, if required.

Educate the workmen through pep-talk meeting. 

Preparatory works:

Toilet plumbing lines are installed in Blockwork and chases are rendered with non-shrink grout prior to cleaning activity of sunk is undertaken.

Cleaning of sunken slab base and sides of beams shall be carried out as regards all those materials, mortar, oil etc. thoroughly by wire brush and the area shall be washed clean.

PVC sleeves should be removed.

Sunken slab should be filled with water and next day should be inspected for leakages.

If Leakages found, then cracks should be open out by making grove and pressure grouting by socket should be done. After completion of treatment sunken slab should be again recheck for any leakages.

Work Method:

Base coat using cement mortar in proportion 1:3 with waterproofing compound (Fosroc Conplast X 421 IC) @ 150ml per bag of cement shall be applied over top of base slab of sunk. Maximum thickness of base coat shall be 25mm at upper end of slope.

Proper slope shall be given to base coat as per drawing towards drain spout and drain spout to be fitted simultaneously with the base coat, as an additional precaution to take care of seepage, if any. Drain spout shall be 25mm in diameter UPVC with GI mosquito mesh coupling to be fixed on both end. It should project at least 4 beyond wall surface.

Base coat shall also be applied to the sides of the toilet sunk up to one foot above the finished floor level (F.F.L) of the adjacent floor. 

Curing of base coat shall be done by ponding for 3 days and checked against leakage. Leakage, if observed shall be rendered with reapplication of base coat to ensure no leakage.

 Floor traps and other plumbing lines shall be installed, Slope of 1:100 shall be provided for toilet piping and water proofing. Floor trap shall be fixed with respect to finished floor level (F.F.L) of the toilet.

Area of pipe which is going through the hole / opening provided in beam should be made rough by applying cement solvent and sprinkling crush sand over it so that bonding between mortar and PVC pipes will be ensured.

Brick bats should be soaked thoroughly for about 15 minutes prior to their placing.

Cement mortar in 1:4 proportions should be prepared and laid on slab. Mortar mixed shall be used within 1Hour of preparation.

 Pre-soaked brick-bats shall then be laid in straight / radial, by inserting brickbats to a depth of about 15mm by light tamping with the help of mallets. Distance between adjacent layers of brickbats shall not exceed25mm.

 Application of brick-bats shall proceed from one corner. Thiyya (level pads) for the same shall be given by Site Engineer, considering into account adequate slope.

Mortar should be filled up to half height of brick bats and it should be cure for minimum 3 days. 

After curing is over, the surface shall be applied with a finishing coat of cement sand mortar in the proportion 1:4 with waterproofing compound (Fosroc Conplast X 421 IC) @ 150ml per bag of cement till top of brick-bats.

 Top coat shall be of neat cement slurry of adequate consistency and shall be done monolithic with topping of brick-bats.

Finished surface shall then be cured for at least 7 days by ponding and then tested for leakages, if any.

IMPORTANT NOTES:

Water-proofing once done, shall not be broken or pierced. If water proofing is to be punctured, due care shall be taken to limit the damage to the restricted area. The cracks due to hammering shall not spread over the large area.

Repairing of the punctured area shall be done by using bonding agent and expansive grouts.

Team

CBEC India

Which material is suitable for sealing tie rod holes of RCC wall? Technical Data Sheet

 PENECRETE MORTOR

DESCRIPTION

PENECRETE MORTAR consists of Portland cement, specially treated quartz sand, and a compound of active chemicals. The active chemicals react with moisture and the by-products of cement hydration to cause a catalytic reaction, which generates an insoluble integral crystalline complex. These crystalline complexes grow in the presence of water and block the capillaries of the concrete and minor shrinkage cracks, thus waterproofing the concrete. Chemical activation begins when the powder is mixed with water and may take several days to completely block the capillaries, depending on ambient temperature and environmental conditions.

APPLICATIONS

Applied in conjunction with PENETRON for: Installation of seal strips, reglets and coves at joints to assure water tightness Patching of tie holes and faulty construction joints Patching and filling of routed out cracks Repairing of spalled and honeycombed areas.

ADVANTAGES

Can be applied to the positive or negative water pressure sides of a structure Resists strong hydrostatic pressure Seals cracks up to 1/64” (0.4 mm) Easy to use – needs only to be mixed with water prior to application Allows the concrete to “breathe” Can be skim coated or feather edged Can be applied to moist concrete Fast setting Inorganic – contains no polymers NSF 61 certified for use in potable water applications Non-flammable Resists abrasion and mechanical wear Freeze/thaw resistant Zero VOC - PENETRON powdered products contain zero volatile organic compounds and are safe for use both outdoors and in confined indoor spaces.

DIRECTIONS FOR USE

Surface preparation:

All surfaces to be patched, repaired, or sealed with PENECRETE MORTAR must be clean and sound. Cracks should be routed out to a U-shaped configuration, approximately 3/4” (19 mm) wide and a minimum of 3/4” (19mm) deep. Tie holes should be roughened prior to filling. Spalled and honeycombed areas must be thoroughly cleaned and chiseled back to sound concrete prior to repair. Remove all dirt, cement laitance, form release agents, curing compounds, paints, coatings, etc. by means of wet or dry sandblasting, high-pressure water jet, or other suitable mechanical means. Surfaces must be well moistened to dull dampness at the time of application. The concrete should be damp with no wet sheen on the surface.

Mixing:

Routed cracks, coves, and non-moving joints: Add water to PENECRETE MORTAR until a medium-stiff, trowelable consistency is reached. The texture of the mix should be pliable enough to be trowelled into the cracks with some pressure, but not so pliable that it would run out or sag out of the crack. The approximate mixing ratio (by volume) is 4.5 parts powder to 1 part water. Alternatively, 3.4 oz (101 ml) of water to 1 lb (454 g) of PENECRETE MORTAR powder.

Tie holes and pointing applications: Add only a small amount of water. Mixed consistency should be that of “dry earth,” holding a shape when squeezed in your hand but easily crumbled when pressed between fingers. Mix only as much material as can be used within 20 minutes.

Application:

Cracks/seal strips (reglets & coves): After proper surface preparation and routing to appropriate configuration, prime areas to be patched or repaired with a slurry coat of PENETRON and while “green” (tacky), fill cavity flush to the surface with PENECRETE MORTAR in mortar consistency.

Spalled and honeycombed areas: Prepare surface and chisel back to sound concrete. Prime area to be repaired with a slurry coat of PENETRON. While still “green” (tacky), apply PENECRETE MORTAR™ in layers of 1/2” (13 mm) not to exceed 2.5“ (6.4 cm). Each layer should be allowed to set long enough that it will leave only a slight indent, approximately 1/16” (1.6 mm) when pressed with a finger. Where possible, the surface of the repair should be packed tightly using a hammer and block of wood. Tie holes and pointing applications: Prepare surface and chisel back to sound concrete. Prime area to be repaired with a slurry coat of PENETRON and while still “green” (tacky), apply PENECRETE MORTAR in “dry earth” consistency. PENECRETE MORTAR should be tightly rodded into tie holes or packed tightly using a hammer and block of wood.

NOTE: For all applications, PENETRON should be applied as a surface treatment as soon as PENECRETE MORTAR has set (approximately 1-2hours). If this is not practical, leave the surface rough for subsequent surface treatment to bond.

Curing:

Provide protection against extreme weather conditions, such as heavy rain or freezing conditions, during the setting period. Curing is not normally required except during hot, low humidity weather. In these conditions, a light mist of water approximately 24 hours after the repair is completed will help to ensure a controlled cure. In extreme dry heat, water misting may be required more frequently.

SPECIAL CONSIDERATIONS

DO NOT apply PENECRETE MORTAR™ at temperatures below 40ºF (4ºC), to a frozen substrate or if temperatures will drop below freezing during the curing period (approximately 24 hours). This product is not recommended for use in expansion joints or other joints designed for movement. PENECRETE MORTAR™ can be applied in 1/2" (13 mm) layers not exceeding 2.5“ (6.4 cm) to prevent shrinkage cracks in the mortar.

CONSUMPTION & YIELD OF 50-LB (22.7-KG) BAG

All values are approximate depending on surface conditions.

U-shaped cracks and reglets

Size 1”x1” (25 mm x 25 mm)

Consumption 1.0 lb/ft² (4.9 kg/m²)

Yield/bag 50 ft (15.2 m)

Coves, triangular shaped

Size 1.5”x1.5” (38 mm x 38 mm)

Consumption 1.0 lb/ft² (4.9 kg/m²)

Yield/bag 50 ft (15.2 m)

Tie holes

Size 1”x1”x1” (25 mm x 25 mm x 25 mm)

Consumption N/A

Yield/bag 600 nos

Honeycomb and surface patching

Approximately 0.4 ft³ (0.01 m³) / bag

PACKAGING

PENECRETE MORTAR is available in 50-lb (22.7-kg) bags or 55-lb (25-kg) pails.

STORAGE / SHELF LIFE

PENETRON products must be stored dry at a minimum temperature of 45ºF (7ºC). Shelf life is one year when stored under proper conditions.

TECHNICAL DATA

Compressive strength (ASTM C-109):

1 day 1600 psi (11 MPa)

3 days 2400 psi (17 MPa)

7 days 5800 psi (40 MPa)

28 days 6900 psi (48 MPa)

Tensile Strength (ASTM C-190):

1 day 320 psi (2.2 MPa)

3 days 520 psi (3.6 MPa)

7 days 730 psi (5.0 MPa)

28 days 900 psi (6.2 MPa)

NOTE: Cooler temperatures, inadequate ventilation, and higher humidity can extend drying times. All

data derived from tests under laboratory conditions; field conditions may yield slightly different results.

TECHNICAL SERVICES

For more detailed instructions, alternative application methods, or information concerning the compatibility of the PENETRON treatment with other products or technologies, contact the Penetron Technical Department or your local Penetron representative.

SAFE HANDLING INFORMATION

PENECRETE MORTAR contains cement that is alkaline. Will irritate eyes and skin and may cause skin sensitization. Wear appropriate eye, skin, and breathing protection when using this product. Avoid contact with skin and eyes. In case of contact with the eyes, rinse immediately with plenty of water and seek medical advice. For further information, please refer to Safety Data Sheet. KEEP OUT OF REACH OF CHILDREN.

THIS IS THE MOST RECOMMENDED AND SAFE MATERIAL AS PER OUR EXPERIENCE.

Team 

CBEC India

External Plaster Work - Standard Work Procedure

External Plaster Work

Introduction:

This standard operating procedure enumerates the scope of External Plasterwork to be executed in the Tower area as specified in the approved drawings and at places when instructed by the Tower-in-charge.

Responsibility: 

The respective Tower-in-charge is responsible to execute the work as per the procedure.

Safety & protection:

Use double scaffolding always and ensure the scaffolding is adequately braced with the permanent structure, for working at heights. Unless it is tagged as safe for use by Safety Officer no work should be carried out on that scaffold area.

PPEs like safety belts at height, helmets, safety goggles, etc. should be used properly. 

Ensure the working area is kept clean for easy access and protect edges of opening by barricading etc while working.

Inspect the scaffolding before starting work.

Proper illumination is to be provided during the work if required.

Educate the workmen through a pep-talk meeting. 

 

Preparatory works:

Complete all external works like Check certificate provided by Safety Officer for scaffolding.

Filling of all vertical and horizontal joints of the block with AAC Block Adhesive.

Filling of the gap between block top and RCC member bottom area with cement mortar and apply non shrink grout on the surface.

Fixing of fiber mesh on all Block to RCC Joints.

Fix level pads (dhada), by tying line thread, from top to bottom, at corners and intermediate distances and it should be checked by the concerned engineer.

Ensure hacking on AAC block and RCC Surface.

Electrical and plumbing fixtures are checked for their alignment.

 Work Method:

 Mortar Preparation:  

The mortar for plastering has to be prepared in a Tray or on metal sheets only. The sand has to be sieved for proper gradation.

The sand has to be washed to remove impurities like a mud if required, and sufficiently dried before plastering work is taken up.

In case wet sand is to be used, check for the quantity of water in a mortar and allow for bulkage of sand while mixing, for ensuring consistency of mortar.

Crush Sand and River Sand should be used in 50:50 proportions.

Do prepare the mortar in proportion as follows;

Bond Coat / Key Coat  1:4 (1 part Cement, 2 Part River Sand, and 2 parts Crush Sand) with waterproofing compound @ 150 ml Per bag of cement (BASF MaterEmaco 141) to be done in thickness 8 to 10 mm.

Finish  Coat  1:3 (1 part Cement, 1.5 Part River Sand and 1.5 parts Crush Sand) with 6mm fibers @ 100 grams per bag of cement ( Strongplast ) and waterproofing compound @ 150 ml Per bag of cement (BASF MaterEmaco 141) to be done in thickness of 12 to 15 mm.

Then do Dabba finish (sand face finish).

Do mix mortar which can be consumed within the next 2 hours.

Do add water to the dry mixed sand and binder (not otherwise).

Bond Coat / Key Coat

Do wet the surface to receive plaster one hour before, so that while starting plastering, the surface is skin dry.

Bond Coat / Key Coat shall be started from the top and worked downwards.

Curing should be done for min 3 Days.

 Finish  Coat

Do throw the mortar for an area coverable by the straight edge, both vertically and horizontally in one stretch.

Do level the surface using the straight edge.

Do float the surface and finish as per specification.

Do repeat this operation for the entire area in stages.

While proceeding with the work, do float and finish the joints in the I stage and then in subsequent stages properly. This is to ensure the stages, in plastering work, are not apparently visible.

Intermediately do check the surface for plumb, line, and level and make up all deficiencies.

If there are grooves in the design, then they should be made at the locations specified.

However, care should be taken to see that the depth of the groove does not cut the base coat or it will lead to leakage.

After making the groove it should be finished neatly with a paste of cement and waterproofing compound. Then do final finishing by brushing.

Do jambs finish in openings in line with internal plaster face or as per level pads and ensure right angles at the corner.

Ensure edge finishing around switchboards is done correctly.

In case of unavoidable situations where the scaffold needs to brace in-wall, the pocket should be sealed and match the plaster finish immediately after removing it.

Curing should be done for min. 7 Days.

After completion of plaster clean the area.

Dos and Do nots:

Do’s:

Do check thoroughly before and immediately after plastering, the line and levels.

Do check thoroughly before and immediately after plastering, the surface areas for unevenness, surface blemishes, etc so that all rectification (if required) can be carried out within the final setting time, without any additional costs.

Do cure the plastering well for the required number of days.

To restrict the access to areas where plastering is complete (This will ensure better protection of edges, corners, angles, etc).

To ensure all touch-ups are done neatly after pre-cast slabs are embedded in position, working platforms are inserted in position, sanitary fixtures are fitted (merging the surfaces being touched up with original surfaces).

Do stop the work preferably in corners, jambs, stoppers or at grooves, etc. This will avoid cracks at joints. To ensure these joints are finished neatly.

Do not:

Do not allow mortar mixing on the unclean areas and in large quantities.

Do not allow usage of partially set mortar.

Do not allow free sprinkling of dry cement in the mortar or on the surface being plastered, as this may cause uneven shrinkage and lead to the development of shrinkage cracks.

Do not mix different brands of cement in the same area as this will show the color difference (till plastered surfaces are covered with some other finish). 

Team

CBEC India