---
title: "Painting a new plastered surface"
subject: "Civil Engineering Materials"
chapter: 9
key: "semester_3/civil_engineering_materials:paint-new-plastered-surface"
source: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/paint-new-plastered-surface
site: BCT Engineering
---

# Painting a new plastered surface

Civil Engineering Materials · Chapter 9: Paint and Varnishes

- Asked in: 2081 Bhadra, 2 marks
- Video: [How i Prepare and Paint New Plaster - Mist Coating Guide](https://www.youtube.com/watch?v=1oNtMDN0ih8) — The DIY Guy
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/paint-new-plastered-surface
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-9

## Question

Describe in steps the procedure of applying paint on a new plastered surface.

## Short answer

Allow plaster to dry fully, clean and repair cracks, apply an alkali-resistant primer, then putty if needed. Follow with an undercoat and two finishing coats, sanding between coats.

## Answer

Steps for painting a new plastered surface:

1. **Drying:** Let the plaster cure and dry fully (at least 2–3 weeks) so alkali and moisture escape.
2. **Cleaning:** Remove dust, loose particles, mortar splashes and efflorescence with a wire brush and dry cloth.
3. **Repair:** Fill cracks and holes with cement or putty, and level with sand paper.
4. **Priming coat:** Apply a coat of alkali-resistant (cement) primer to seal pores and make the paint stick.
5. **Putty/filler:** Apply wall putty if a very smooth surface is needed; sand after drying.
6. **Undercoat:** Apply one coat of undercoat and sand lightly.
7. **Finishing coat:** Apply two coats of the final paint, each after the earlier coat is dry.

## Check yourself

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

1. Why must new plaster dry for 2-3 weeks before painting?
   A. To gain colour
   B. So alkali and moisture escape
   C. To harden the brush
   D. To reduce cost
   Answer: B. Curing lets alkali and moisture escape, otherwise paint is damaged. (Key point: Drying of plaster)

2. Which primer is used on new plaster?
   A. Red lead primer
   B. Shellac knotting
   C. Alkali-resistant (cement) primer
   D. Aluminium paint
   Answer: C. Alkali-resistant primer seals pores and helps paint stick. (Key point: Primer type)

3. What is removed with a wire brush in the cleaning step?
   A. Dust, mortar splashes and efflorescence
   B. The plaster itself
   C. Primer
   D. Putty
   Answer: A. Cleaning removes dust, loose particles, mortar splashes and efflorescence. (Key point: Cleaning)

4. How many finishing coats are applied, and when?
   A. One, wet on wet
   B. Two, each after the earlier coat is dry
   C. Three, immediately
   D. None if putty is used
   Answer: B. Two coats of final paint are applied, each after the previous dries. (Key point: Finishing coats)

## Related in Civil Engineering Materials

- [Painting a new wood surface](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Apaint-new-wood-surface) — Civil Engineering Materials, chapter 9
- [Preparing an older surface for painting](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Apaint-older-surface-preparation) — Civil Engineering Materials, chapter 9
- [Steps of applying cement mortar](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Asteps-applying-cement-mortar) — Civil Engineering Materials, chapter 6

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