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Calculate mortar quantities for brickwork and blockwork. Supports multiple mix ratios with cement and sand breakdown. Free construction calculator.
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Calculate cement, sand, and water volumes for brickwork, blockwork, plastering, and tiling mortar using IS, BS, and ASTM mix specifications.
Mortar is the bonding agent between masonry units. It fills joints, transfers loads uniformly, and provides weathertightness. Quantity estimation starts with the volume of mortar joints in the finished work. For standard brickwork: joint volume ≈ 30% of the gross wall volume.
The key step is applying the dry-to-wet volume factor (1.35): mortar shrinks when mixed because water fills the void space between dry particles. So 1 m³ of dry mix ingredients becomes ≈ 0.74 m³ of wet mortar. To get 1 m³ of mortar, you need 1.35 m³ of dry ingredients.
Mix ratios (cement : sand by volume) determine ingredient quantities. A 1:6 mix has 7 total parts: cement volume = 1/7 × 1.35 = 0.193 m³ per m³ of mortar needed. Sand = 6/7 × 1.35 = 1.157 m³. Convert cement volume to bags: 0.193 ÷ 0.0347 = 5.6 bags per m³ of mortar.
V_mortar = V_wall × 0.30Standard 230×115×75 mm bricks with 10 mm joints: joint volume ≈ 30% of gross wall volume. Adjust for actual brick size and joint thickness.
V_dry = V_mortar × 1.35The dry-to-wet factor 1.35 accounts for air voids between dry particles that collapse when water is added and mix is worked.
V_c = [1/(1+n)] × 1.35n = sand parts. For 1:6: V_c = (1/7)×1.35 = 0.193 m³. Convert to bags: ÷ 0.0347 m³/bag = 5.56 bags per m³.
V_s = [n/(1+n)] × 1.35For 1:6: V_s = (6/7)×1.35 = 1.157 m³. Convert to weight: × 1500 kg/m³ (loose) = 1736 kg per m³ of mortar.
| Mix Ratio (C:S) | IS Designation | Compressive Strength | Application | Notes |
|---|---|---|---|---|
| 1:3 | MM 10 (strong) | ≥10 N/mm² | RCC precast joints, grout | High cement; prone to cracking |
| 1:4 | MM 5 | ≥5 N/mm² | External plaster, DPC course | Good strength + workability |
| 1:5 | MM 3 | ≥3 N/mm² | Internal plaster, brick coping | Balanced mix |
| 1:6 | MM 1.5 | ≥1.5 N/mm² | Internal brickwork, masonry | Most common masonry mortar |
| 1:8 | Lean mix | < 1 N/mm² | Filling, non-structural | Not for load-bearing walls |
| Lime + cement | FL type | Varies | Repointing heritage masonry | More flexible, breathable |
Earliest known use of mud mortar in Mesopotamia to bond sun-dried mud bricks. Some of the world's oldest structures in Jericho used lime-burned plaster as a floor finish — among the first processed binding materials.
Egyptians used gypsum mortar (calcined from calcium sulphate) in the construction of the pyramids. The joints in the Great Pyramid are remarkably fine — 0.5 mm in places — requiring a highly fluid, precisely proportioned mortar.
Romans developed hydraulic lime mortar (opus signinum) and later pozzolanic mortar using volcanic ash from Pozzuoli, Italy. This mortar hardened underwater — revolutionary for harbour and bridge construction.
Joseph Aspdin patented Portland cement, quickly replacing pure lime mortars in structural applications. Portland cement mortars are much stronger and faster-setting but less flexible than pure lime mortars.
Plasticiser admixtures introduced to improve mortar workability without increasing water content. Ready-mixed mortar (factory-batched dry mix or wet retarded mix) became available, improving site consistency.
Polymer-modified mortars (tile adhesives, repair mortars, self-levelling screeds) now widely used. Dry premix mortars dominate residential tiling and flooring. High-bond epoxy grouts used in chemical-resistant tiling.
Indian Standard code of practice for preparation and use of masonry mortars including mix designation, constituent materials, workmanship, and curing requirements.
Read source →European standard specifying mortar for masonry including compressive strength classes M1–M20, water retention, and durability requirements for factory and site-mixed mortars.
Read source →US standard specifying Types M, S, N, O, K mortar by proportions and properties including compressive strength, water retention, and air content limits.
Read source →More cement in mortar makes stronger masonry walls
Over-rich mortar (1:3) is stronger than the brick/block units and transfers cracks into the units rather than the joints. IS 2250 recommends 1:6 for internal brickwork — mortar should be weaker than the unit so cracks appear in repairable joints, not through the masonry.
1 m³ dry materials = 1 m³ of mortar
Due to the dry-to-wet volume factor (1.35), 1.35 m³ of dry ingredients is needed to produce 1 m³ of mixed mortar. Ignoring this leads to ordering 35% too little material, causing work stoppages.
Any sand can be used for mortar
IS 2116 specifies fine aggregate for masonry mortars: clean, well-graded sand with <4% clay and silt. Dirty or salty sand causes efflorescence, reduces adhesion, and leads to joint failure. Sea sand must never be used without washing.
Mortar can be retempered (adding water) after it starts to stiffen
Retempered mortar has reduced bond strength due to partial hydration of cement. IS 2250 mandates using mortar within 30 minutes of mixing for ordinary Portland cement mortars. Retarded ready-mix mortars are specifically designed for extended working times.
Never run short on site — calculate cement, sand, and water before you mix.