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

# Multiplying factors for painting doors

Estimating and Costing · Chapter 2: Method of Estimating

- Asked in: 2076 Asoj, 2 marks
- Video: [IS 1200 Part 13 - Mode of Measurement of Paint Works for Construction Billing and Costing](https://www.youtube.com/watch?v=DIaHw5tTWlM) — Factual Civil Engineering
- 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-painting-doors
- Whole chapter: https://www.bctengineer.com/md/semester_7/estimating_and_costing/chapter-2

## Question

Explain the multiplying factors adopted in painting of panelled door, flush door, louver door and glazed window.

## Short answer

For painting, measure the door or window opening area including frame and multiply by a factor per side: panelled door 1.30, flush door 1.20, louvered door 1.80, glazed window or door 0.80. These account for extra panel, slat and frame surfaces.

## Answer

Painting of doors and windows is measured as the **area of the opening** (length x breadth, including the frame), taken on one face. Because the actual surface is larger than this plain area (panels, mouldings, louvers, edges, frame, etc.), the area is multiplied by a factor that accounts for the extra surface. Typical factors as per IS 1200 (Part 15), for each side painted:

| Type of door/window | Multiplying factor |
|---|---|
| Panelled, framed and braced door | 1.30 |
| Flush door | 1.20 |
| Louvered (venetian) door | 1.80 |
| Glazed (fully glazed/sash) window or door | 0.80 |

Reasons: a panelled door has recessed panels and mouldings, so its surface area exceeds the plane area by about 30%. A flush door has a flat face, and only the edges and the frame add to it, so the factor is slightly above 1. A louvered door has angled slats exposed on both sides, so the factor is large. In a glazed one, part of the opening is covered by glass, so less surface needs painting, though the frame, bars and edges still do.

Example: panelled door 1.0 x 2.1 m = 2.1 m²; painting area per side = 2.1 x 1.30 = 2.73 m². The factors should be checked against the current edition of the IS code or the Nepal norms used.

## Check yourself

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

1. On what area is painting of a door measured before applying the factor?
   A. The actual unfolded surface of each panel
   B. The weight of paint used
   C. The perimeter of the frame
   D. The area of the opening (length x breadth, including frame), one face
   Answer: D. The opening area is multiplied by a factor that accounts for the extra surface. (Key point: Measurement basis)

2. A panelled door 1.0 x 2.1 m is painted per side. What is the painting area?
   A. 2.73 m2
   B. 2.10 m2
   C. 3.78 m2
   D. 1.68 m2
   Answer: A. 2.1 x 1.30 = 2.73 m2. (Key point: Example)

3. Why is the factor for a glazed window (0.80) less than 1?
   A. Glass absorbs more paint
   B. Part of the opening is covered by glass, so less surface needs painting
   C. Glazed windows are painted only once
   D. The frame is not painted
   Answer: B. The glass is not painted, though frame, bars and edges still are. (Key point: Glazed factor)

## Related in Estimating and Costing

- [Multiplying factors: panelled and louver door](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Amultiplying-factors-panelled-louver) — Estimating and Costing, chapter 2