---
title: "Detailed specification of brick work in 1:4 mortar"
subject: "Construction Management"
chapter: 12
key: "semester_8/construction_management:detailed-spec-brick-1-4"
source: https://www.bctengineer.com/q/semester_8/construction_management/detailed-spec-brick-1-4
site: BCT Engineering
---

# Detailed specification of brick work in 1:4 mortar

Construction Management · Chapter 12: Specification

- Asked in: 2079 Shrawan; 2071 Bhadra, 5 marks; 2070 Magh, 7 marks; 2067 Mangsir (old course), 16 marks (asked 4 times)
- Video: [part-10 First class  Brick work detailed specifications](https://www.youtube.com/watch?v=NG1k-2m-vqw) — Super civilian 
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_8/construction_management/detailed-spec-brick-1-4
- Whole chapter: https://www.bctengineer.com/md/semester_8/construction_management/chapter-12

## Question

Write a detailed specification for brick work in 1:4 cement sand mortar.

## Short answer

The spec covers first-class bricks soaked 2h, OPC cement, clean sand (1:4 by volume), English bond with 10mm joints, mortar used within 30 min, curing 7 days. Measurement is in cubic metres net, including all labour and materials.

## Answer

#### Detailed specification: brick work in cement sand mortar 1:4

**1. Scope:** Providing and constructing brick masonry in superstructure/foundation in cement sand mortar 1:4 (1 part cement : 4 parts sand by volume), complete as per drawings and instructions of the engineer.

**2. Materials**
- **Bricks:** first-class, well burnt, uniform in colour, shape and size (typically 240 × 115 × 57 mm in Nepal), with sharp edges, giving a metallic ring when struck. Compressive strength as specified (first-class bricks normally not less than about 10 N/mm², and in no case less than 3.5 N/mm², the NBC minimum); water absorption not more than 20% after 24 hours; free from cracks, lime lumps and salts. Bricks are soaked in clean water for at least 2 hours (until bubbles stop) before laying.
- **Cement:** OPC 43 grade or PPC conforming to NS/IS, fresh and free from lumps; stored in a dry store on a raised platform.
- **Sand:** clean, hard, coarse river sand, free from clay, silt, mica, organic matter and salt; fineness modulus 1.5–2.5; silt content < 4%.
- **Water:** clean, potable, free from oil, acid, alkali and organic matter.

**3. Mortar:** Cement and sand are measured in boxes by volume (1 : 4), dry-mixed to a uniform colour, then mixed with the minimum water for a workable consistency. Mixing is done on a clean watertight platform or in a mixer. Only the quantity that can be used within **30 minutes** is mixed; mortar that has begun to set is not retempered or used.

**4. Workmanship**
- The foundation bed is cleaned, levelled and wetted.
- The work is laid in **English bond** (or the bond shown in the drawing), with full headers and stretchers, and the vertical joints of alternate courses kept in line (perpends) to maintain plumb.
- Bricks are laid frog up, pressed into a full bed of mortar, and all joints are completely filled.
- Mortar joints are 10 mm thick (not more than 12 mm). The face joints are raked 12–15 mm deep while the mortar is green if the wall is to be plastered, or finished flush/struck if pointing is specified.
- The walls are raised uniformly, by not more than 1 m in one day; the work is kept plumb and level with a plumb bob, spirit level and line, and the surface is checked with a straight-edge.
- Where the work has to be stopped, it is raked back (stepped) according to the bond; toothing is left only where future extension is planned, with the engineer's approval.
- Openings, lintels, sills and the bearings of beams are as per the drawing; holes for services are provided.

**5. Curing and protection:** The brickwork is kept wet for **at least 7 days** by sprinkling, and protected from sun, rain and damage.

**6. Tolerance and testing:** Deviation from plumb should not exceed 5 mm per 3 m height, and wall thickness should be within ±5 mm. Samples of bricks (compressive strength, absorption) and mortar cubes may be tested as the engineer instructs.

**7. Measurement and payment:** The work is measured in **cubic metres** of finished masonry, to the net dimensions as built, deducting openings and other voids larger than 0.1 m²; there is no separate payment for scaffolding, curing and cleaning. Payment is at the contract rate per m³, which includes all materials, labour, tools, scaffolding, curing and wastage.

## Check yourself

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

1. How should the 1:4 mortar be prepared and used according to the specification?
   A. Dry-mixed by volume to uniform colour, minimum water, used within 30 minutes, never re-tempered
   B. Mixed wet from the start and reused after re-tempering
   C. Mixed by weight and used within 2 hours
   D. Mixed with plenty of water for easy flow and used the same day
   Answer: A. The mortar is measured by volume (1:4), dry-mixed, wetted minimally, and used within 30 minutes; set mortar is not retempered. (Key point: Mortar mixing and use)

2. Which set of brick requirements matches the specification?
   A. Compressive strength at least 1 N/mm2, absorption up to 30%, laid dry
   B. Compressive strength at least 3.5 N/mm2, absorption at least 20%, laid dry
   C. Compressive strength at least 3.5 N/mm2, water absorption at most 20%, soaked at least 2 hours
   D. Any colour and size, soaked for 10 minutes
   Answer: C. First-class bricks need at least 3.5 N/mm2 strength, absorption not above 20% and soaking for at least 2 hours. (Key point: Brick requirements)

3. Which workmanship rule is correct?
   A. Joints 10 mm (max 12 mm), full bed of mortar, maximum 1 m raising per day, toothing left for new work
   B. Joints 20 mm thick and raising up to 3 m a day
   C. Joints left unfilled to save mortar, raked-back ends
   D. Bricks laid with frogs down, any bond
   Answer: A. Joints are 10 mm, completely filled, height limited to 1 m per day, and toothing (not raking back) is left for joining. (Key point: Workmanship rules)

4. How is the work cured and measured?
   A. Cured 1 day and measured in square metres
   B. Cured 28 days and measured in kg
   C. Cured at least 7 days and measured in m3 of net finished masonry, deducting openings over 0.1 m2
   D. Not cured and measured by number of bricks only
   Answer: C. Brickwork is kept wet for at least 7 days and measured in cubic metres net, with voids over 0.1 m2 deducted. (Key point: Curing and measurement)

## Close variants set in other exams

- [Detailed specification of brick work in 1:6 mortar](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Adetailed-spec-brick-1-6) — Construction Management, chapter 12, asked 5×

## Related in Construction Management

- [Detailed specification of cement sand mortar 1:4](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Adetailed-spec-cs-mortar-1-4) — Construction Management, chapter 12, asked 2×
- [Detailed specification of cement sand mortar 1:6](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Adetailed-spec-cs-mortar-1-6) — Construction Management, chapter 12, asked 2×
- [Detailed specification of cement plaster 1:4](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Adetailed-spec-plaster-1-4) — Construction Management, chapter 12
- [Detailed specification of stone masonry in 1:6 mortar](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Adetailed-spec-stone-masonry-1-6) — Construction Management, chapter 12
- [Types of specification: general and detailed](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Aspec-types-general-detailed) — Construction Management, chapter 12, asked 7×
- [Detailed specification of RCC M20 column](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Adetailed-spec-rcc-m20-column) — Construction Management, chapter 12

## Related in other subjects

- [Mortar properties; cement and sand for 10 cum](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Amortar-quantity-10cum) — Building Technology, chapter 3
- [Well foundation: sinking, brick, sand filling, PCC](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Awell-foundation-g-sand-filling) — Estimating and Costing, chapter 6, asked 2×
- [Building: excavation, brick 1:4, wood work](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Abuilding-k-fig1) — Estimating and Costing, chapter 6
- [Building: excavation, PCC, brick, wood work](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Abuilding-f-fig3-four-items) — Estimating and Costing, chapter 6