---
title: "Bay and dormer windows"
subject: "Building Technology"
chapter: 6
key: "semester_6/building_technology:bay-dormer-window"
source: https://www.bctengineer.com/q/semester_6/building_technology/bay-dormer-window
site: BCT Engineering
---

# Bay and dormer windows

Building Technology · Chapter 6: Doors and windows

- Asked in: 2076 Bhadra, 2 marks
- Video: [Bay Window](https://www.youtube.com/watch?v=gkFgYBJTEyA) — Brian Anderson
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/building_technology/bay-dormer-window
- Whole chapter: https://www.bctengineer.com/md/semester_6/building_technology/chapter-6

## Question

Describe about bay and dormer window.

## Short answer

A bay window projects outward from the wall line with three sides, providing more light, view and floor area. A dormer window is a vertical window set in a sloping roof with its own small roof, used to light and ventilate attic spaces.

## Answer

**Bay window:** a window that projects outward from the wall line of the building, with three sides (usually 3 shutters at 90 or 135 degrees) forming a bay. It increases floor area, gives more light, a wide view and ventilation, and is used in living rooms and bedrooms.
```text
 PLAN
    ___________
   /           \
  /  bay window \
 ======wall=======
```
**Dormer window:** a vertical window built in the sloping roof, with its own small gable or sloping roof. It gives light and ventilation to the attic or room under the roof.
```text
      /\
     /  \
    /[]  \  <- dormer window in roof slope
   /______\
```

## Check yourself

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

1. A bay window is one that
   A. Lies in the roof slope
   B. Projects outward from the wall line
   C. Is placed at eye level only
   D. Is fixed with no frame
   Answer: B. A bay window projects outward from the wall, increasing floor area, light and view. (Key point: Bay window)

2. A dormer window is
   A. A curved bay
   B. A window at the corner of walls
   C. A vertical window in a sloping roof with its own small roof
   D. A glass sheet in the roof slope
   Answer: C. A dormer is vertical and projects from the roof, lighting the attic. (Key point: Dormer window)

3. What does a dormer window give?
   A. Light and ventilation to the attic or room under the roof
   B. Privacy to bathrooms
   C. Cross ventilation at corners
   D. A strong door frame
   Answer: A. It provides light and ventilation to rooms under a sloping roof. (Key point: Use of dormer)

## Related in Building Technology

- [General parts of doors and windows](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Adoor-window-parts) — Building Technology, chapter 6, asked 2×
- [Casement, louvered and corner windows](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Acasement-louvered-corner) — Building Technology, chapter 6
- [Door/window components and door types](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Adoor-window-components-types) — Building Technology, chapter 6

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- [EVA; 100 precast windows in 20 days](https://www.bctengineer.com/question.md?key=semester_7%2Fproject_engineering%3Aeva-precast-windows-c70) — Project Engineering, chapter 4
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