---
title: "Roof covering materials for pitched roof"
subject: "Building Technology"
chapter: 4
key: "semester_6/building_technology:roof-covering-types"
source: https://www.bctengineer.com/q/semester_6/building_technology/roof-covering-types
site: BCT Engineering
---

# Roof covering materials for pitched roof

Building Technology · Chapter 4: Roofs

- Asked in: 2079 Chaitra, 2 marks; 2078 Baisakh, 4 marks; 2076 Baisakh, 4 marks (asked 3 times)
- Video: [Which Roofing Material is Right For Your Home?](https://www.youtube.com/watch?v=pNDH_bC_MH0) — Fixr
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/building_technology/roof-covering-types
- Whole chapter: https://www.bctengineer.com/md/semester_6/building_technology/chapter-4

## Question

Explain different types of roof covering materials for pitched roof.

## Short answer

Pitched roof coverings: thatch (cheap, insulating, fire risk, 45-60° slope), clay tiles (durable, heavy, 25-45° slope), slates (durable, fireproof, costly), stone slabs (heavy, hilly areas), AC sheets (light, fire resistant, asbestos hazard), GI/CGI sheets (light, quick fixing, noisy, common in Nepal), aluminium/coloured steel (rust-resistant, costly), plastic/polycarbonate (translucent, low strength), wooden shingles (insulating, fire risk).

## Answer

Roof covering is the outer weather-proof layer laid over the rafters/battens of a pitched roof. The choice depends on climate, slope, cost and availability.

| Covering | Main properties and use |
|---|---|
| Thatch (straw, khar, reed) | Cheapest, good insulation, high fire risk, needs 45-60 degree slope, short life |
| Clay tiles (country, Mangalore, Allahabad) | Good insulation, durable, heavy, need close battens; slope 25-45 degrees |
| Slates | Durable, fire resistant, neat; heavy and costly; slope above 25 degrees |
| Stone slabs (patthar) | Used in hilly Nepal; very heavy, durable, needs strong rafters |
| AC (asbestos cement) sheets | Cheap, light, fire resistant; brittle, health hazard (asbestos) |
| GI / CGI sheets | Light, easy and quick fixing, durable if coated; noisy, hot, can corrode |
| Aluminium / coloured steel sheets | Light, rust-resistant, many colours; costly |
| Plastic / fibre / polycarbonate sheets | Light, translucent; low strength, UV ageing |
| Wooden shingles | Good insulation, attractive; fire risk, decay |

#### Brief notes
- **Thatch:** bundles of straw or reeds tied on bamboo/timber battens at 45-60 degree slope; cheap and cool but burns easily.
- **Tiles:** clay tiles (Mangalore, country tile) hung on battens; good thermal comfort and durable.
- **Slate:** thin sheets fixed with nails; very durable, fire proof, expensive.
- **AC and CGI sheets:** large light sheets fixed by hook bolts to purlins; quick and economical, CGI most common in Nepal.
- **Stone slate (patthar):** used in hilly regions of Nepal, very heavy.

## Check yourself

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

1. Thatch is?
   A. Cheapest, good insulation, fire risk, 45-60 degree slope
   B. Durable
   C. Heavy
   D. Fireproof
   Answer: A. Thatch burns easily. (Key point: Thatch)

2. Disadvantage of AC sheets?
   A. Brittle and asbestos health hazard
   B. Heavy
   C. Noisy
   D. Costly
   Answer: A. Cheap, light but hazardous. (Key point: AC sheets)

3. Stone slabs are used in?
   A. Plains
   B. Factories
   C. Hilly Nepal; very heavy
   D. Domes
   Answer: C. Need strong rafters. (Key point: Stone slabs)

4. CGI sheets are?
   A. Light, quick to fix but noisy and hot
   B. Fireproof stone
   C. Heavy
   D. Brittle
   Answer: A. Most common in Nepal. (Key point: CGI)

## Related in Building Technology

- [Factors for selecting roof covering](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Aroof-covering-factors) — Building Technology, chapter 4, asked 2×
- [Roof covering; double and triple roofs](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Aroof-covering-double-triple) — Building Technology, chapter 4
- [Define pitched roof and its types](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Adefine-pitched-roof-types) — Building Technology, chapter 4, asked 4×
- [Terms used in a pitched roof](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Aroof-terminology) — Building Technology, chapter 4, asked 4×
- [Flat roof versus pitched roof](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Aflat-vs-pitched) — Building Technology, chapter 4, asked 2×
- [Requirements of good roof; pitched roof types](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Aroof-requirements-pitch-066j) — Building Technology, chapter 4

## Related in other subjects

- [Wind pressure on pitched roof on hill](https://www.bctengineer.com/question.md?key=semester_6%2Fdesign_of_steel_and_timber_structure%3Awind-pitched-roof-eaves-10m) — Design of Steel and Timber Structure, chapter 8
- [Materials for PCC roof 1:1.5:3 with rebar](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Amaterials-pcc-rcc-roof-g) — Estimating and Costing, chapter 4
- [Surface plate: materials, grades and use](https://www.bctengineer.com/question.md?key=semester_3%2Fmetrology%3Asurface-plate-materials-and-uses) — Metrology, chapter 6