Plastering ke liye kitna cement aur reti — 1:4 aur 1:6 mix

Plaster patla lagta hai, isliye log material underestimate karte hain jab tak mason beech kaam mein agle bags na maange। Plaster ke liye cement aur reti estimate karna simple hai agar ise deewar par chipki patli slab samjhein: area × thickness → volume → dry factor → ratio se split।

Mix ratio chunein

Indian sites par deewar plaster ke liye do cement–reti ratio constantly dikhte hain:

| Use | Common ratio | Notes | |-----|--------------|--------| | Andar ki deewar / finishing coat | 1 : 4 | Richer mix, smooth finish | | Bahar ki deewar / rough ya backing coat | 1 : 6 | Leaner, aksar bahar ya pehli coat |

Yeh common site conventions hain, har building ka ek law nahi। Architect ya contract kuch aur specify kar sakta hai (jaise 1:5, alag coats)। Tender mein ratio ho to wahi use karein। Ghar plaster plan karte waqt mason ke saath 1:4 andar aur 1:6 bahar familiar starting point hai।

Typical plaster thickness

Thickness aksar millimetres mein:

• Andar plaster: 12 mm single coat finish ke liye bahut common
• Bahar plaster: aksar 15–20 mm, kabhi do coats mein

Moti plaster reti aur cement tezi se khaati hai। 12 mm se 20 mm chhota change nahi — same deewar area par roughly two-thirds zyada material।

Calculation method

1. Deewar area

Rectangular deewar face ke liye:

Area = lambai × unchai

Tight number ke liye darwaze-khidki minus karein। Bahut rough estimates chhote openings ignore karke thodi extra reti accept karte hain।

2. Plaster ka wet volume

Thickness metres mein (12 mm = 0.012 m):

Wet volume = area × thickness

3. Dry volume

Mortar ko dry-volume allowance chahiye। Plaster/mortar ke liye commonly 1.33 (kuch 1.30 use karte hain):

Dry volume = wet volume × 1.33

Yeh sand/cement ke voids aur apply karte waqt wastage cover karta hai।

4. Cement aur reti split

Ratio 1 : N (cement : reti) ke liye:

• Cement volume = dry volume × (1 ÷ (1+N))
• Reti volume = dry volume × (N ÷ (1+N))

Cement ko 50 kg bags mein: ≈ 0.0347 m³ per bag (50 kg, ~1440 kg/m³ bulk density)। Reti usually cft mein order (m³ se × 35.315)।

Worked example: 100 sq ft andar ki deewar, 12 mm, 1:4

Bahut clients ab bhi square feet mein sochte hain। 100 sq ft deewar area lein।

Area m² mein:

100 sq ft ÷ 10.764 ≈ 9.29 m²

Thickness 12 mm = 0.012 m

Wet volume = 9.29 × 0.012 ≈ 0.111 m³

Dry volume = 0.111 × 1.33 ≈ 0.148 m³

1:4 mix → parts = 5

• Cement = 0.148 × (1/5) ≈ 0.030 m³ ≈ 0.85 bags → order 1 bag (returns/wastage ho to 2 rakhein)
• Reti = 0.148 × (4/5) ≈ 0.118 m³ ≈ 4.2 cft

To roughly 100 sq ft single-coat 12 mm plaster 1:4 par 1 bag cement aur 4–5 cft reti plan karein, thoda wastage aur uneven deewar ke liye extra। Poore kamre ke liye total plaster area se multiply (deewar + shayad ceiling)।

Same 100 sq ft 1:6 par (leaner)

Cement share kam: 0.148 × (1/7) ≈ 0.021 m³ ≈ 0.6 bags → chhote kaam mein phir bhi round up। Reti badhti: 0.148 × (6/7) ≈ 0.127 m³ ≈ 4.5 cft। Leaner mix cement bachata hai par finished andar ki surface ke liye hamesha desired nahi।

Manual math skip karein — Plastering Calculator se turant result. Deewar area, thickness, 1:4 ya 1:6 — cement bags aur reti cft mein milega।

Andar vs bahar — practical notes

• Andar 1:4 ~12 mm — bahut gharon ke liye standard planning assumption
• Bahar 1:6 ~15–20 mm — zyada reti, zyada volume; waterproofing aur curing ratio jitne matter karte hain
• Do coats — har coat ki thickness alag calculate karke jodein, ya total thickness agar contract ek build-up maane
• Ceiling plaster — same formula; area kamre ki lambai × chaudai

Uneven eentwork mason ko kahi mota plaster lagaane par majboor kar sakti hai। Isliye spreadsheet perfect dikhe tab bhi extra reti khatam ho jati hai।

Reti aur cement order

• Plaster ke liye dhuli reti prefer karein (concrete wali coarse reti nahi)
• Cement: wahi 50 kg bags; dry rakhein
• Sirf utna mix karein jitna team stiff hone se pehle use kar le
• Paani: zyada paani plaster kamzor karta hai, baad mein crack

FAQ

Kya 1:4 hamesha andar aur 1:6 bahar?

India mein bahut common site habit hai, estimation courses aur contractors use karte hain। Sirf sahi choice nahi। Spec ho to follow karein; na ho to 1:4 / 1:6 planning default।

Darwaza-khidki area minus karein?

Bill of quantities ke liye haan। Chhote kamre ke liye bahut log “gross wall area” plaster karke surplus accept karte hain। Bade openings (main door, badi khidki) minus karna worth hai।

100 sq ft par sirf ek bag? Kam lagta hai।

12 mm par plaster volume chhota hai — sau square feet us area par sirf centimetre bhar thickness hai। Cement us volume ka fraction hai। Poore ghar ke plaster mein bahut bags lagte hain kyunki total deewar area bada hota hai।

Plaster ke liye concrete wala 1.54 dry factor use kar sakte hain?

Mortar/plaster factor (~1.33) behtar hai। 1.54 se plaster material zyada dikhega।

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Saari Hindi guides dekhein, ya bag-to-cft conversion ke liye Bharat mein cement bag size padhein।