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Openings in this wall
| Type | Width (m) | Height (m) | Nos | Deduct / add (m²) | |
|---|---|---|---|---|---|
Result
Rules from IS 1200 (Part 12) clause 3.8. Departments sometimes follow their own practice — check before submitting.
How it’s calculated
Questions
What are the IS 1200 rules for openings in plaster?
Openings up to 0.5 m²: no deduction and nothing added for jambs. 0.5–3 m²: with the same plaster on both faces, deduct one face only (other cases per clause 3.8.1). Above 3 m²: deduct on each face and measure jambs, soffits and sills separately.
Why is a 0.5–3 m² opening deducted from one face only?
Because the plaster on the jambs, soffit and sill of such openings is not measured separately; deducting one face only roughly makes up for that work.
Does the same rule apply to painting?
Painting and finishing are measured under their own part of IS 1200, which follows a similar approach — check the part that applies to your item.
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