---
title: "Multiplying factors: panelled and louver door"
subject: "Estimating and Costing"
chapter: 2
key: "semester_7/estimating_and_costing:multiplying-factors-panelled-louver"
source: https://www.bctengineer.com/q/semester_7/estimating_and_costing/multiplying-factors-panelled-louver
site: BCT Engineering
---

# Multiplying factors: panelled and louver door

Estimating and Costing · Chapter 2: Method of Estimating

- Asked in: 2076 Chaitra, 2 marks
- Video: [How to Measure Wooden Work Painting Work a per CPWD | Measurement of Paint Works || By CivilGuruji](https://www.youtube.com/watch?v=kamFhND4MTo) — The Institute of Construction Managment 
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/estimating_and_costing/multiplying-factors-panelled-louver
- Whole chapter: https://www.bctengineer.com/md/semester_7/estimating_and_costing/chapter-2

## Question

Explain the multiplying factors adopted for panelled door and louver door.

## Short answer

Painting quantity equals opening area (width x height) times the factor per side. Panelled door uses 1.30 and louvered door uses 1.80, so a 1.0 x 2.1 m door gives 2.73 m2 and 3.78 m2 per side respectively.

## Answer

Doors are painted over a larger surface than the plain opening area because of panels, mouldings and slats. To simplify measurement, the **area of the door opening (including the frame)** is multiplied by a factor.

| Door | Multiplying factor (IS 1200 Part 15, per side) | Reason |
|---|---|---|
| Panelled door | 1.30 | Recessed panels, mouldings and rails give about 30% extra surface |
| Louvered (venetian) door | 1.80 | Inclined slats are exposed on both faces and their edges; the surface is nearly double |

Use: painting quantity = width x height of the door opening x factor (for each painted side). For example, a panelled door of 1.0 x 2.1 m painted on one side = 2.1 x 1.30 = 2.73 m², and a louvered door of the same size = 2.1 x 1.80 = 3.78 m².

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Why is the door opening area multiplied by a factor in painting?
   A. To allow for paint wastage
   B. To include the wall around the door
   C. Panels, mouldings and slats make the real surface larger than the plain area
   D. To convert m2 to m3
   Answer: C. The factor simplifies measurement of the extra surface. (Key point: Why a factor)

2. A louvered door of 1.0 x 2.1 m painted on one side has a painting quantity of:
   A. 2.73 m2
   B. 2.10 m2
   C. 4.20 m2
   D. 3.78 m2
   Answer: D. 2.1 x 1.80 = 3.78 m2. (Key point: Louvered example)

3. Why is the louvered door factor (1.80) higher than that of a panelled door (1.30)?
   A. Inclined slats are exposed on both faces and edges, giving nearly double the surface
   B. Louvered doors are thicker
   C. Louvered doors need two coats by rule
   D. They have no frame
   Answer: A. The slat surfaces make the area nearly double the opening. (Key point: Louvered factor reason)

## Related in Estimating and Costing

- [Multiplying factors for painting doors](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Amultiplying-factors-painting-doors) — Estimating and Costing, chapter 2
- [Building with verandah: excavation, panelled shutter, brick](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Abuilding-n-fig3-three-items) — Estimating and Costing, chapter 6

## Related in other subjects

- [Plan and vertical section of panelled door](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Apanelled-door-plan-section) — Building Technology, chapter 6