---
title: "Methods of preserving stone"
subject: "Civil Engineering Materials"
chapter: 2
key: "semester_3/civil_engineering_materials:preservation-of-stone"
source: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/preservation-of-stone
site: BCT Engineering
---

# Methods of preserving stone

Civil Engineering Materials · Chapter 2: Building Stones

- Asked in: 2081 Bhadra, 2 marks; 2075 Asoj, 2 marks; 2078 Bhadra, 2 marks; 2069 Chaitra, 3 marks (asked 4 times)
- Video: [Preservation of Stones](https://www.youtube.com/watch?v=062o_gF9kuw) — Mounika Ganta
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/preservation-of-stone
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-2

## Question

List out the methods of preservation of stone from deterioration.

## Short answer

Preservation methods include selecting dense, low-porosity stone and seasoning it; placing with bed perpendicular to load; smooth dressing; applying coatings like linseed oil, silicone, or baryta water; chemical treatments (fluosilicates); and regular cleaning and pointing to keep pores sealed.

## Answer

Preservation protects a stone from weathering and chemical attack so that it lasts longer. The main methods are:

1. **Proper selection and seasoning:** choose a dense, low-porosity stone and allow the quarry sap to dry out before use.
2. **Correct placing:** lay stratified stones with their natural bed perpendicular to the load, and give projecting parts a drip course.
3. **Good drainage and design:** avoid water pockets; provide slopes, copings and damp-proof courses.
4. **Smooth, fine dressing:** a smooth surface sheds water and dust.
5. **Coating with paints or varnish:** oil paint, linseed oil, or a coat of wax or silicone to seal the pores.
6. **Surface treatment (solutions):** application of baryta water (barium hydroxide), a solution of alum and soap, or silicone water repellents.
7. **Chemical treatment:** treatment with fluosilicate solutions (Kessler's process) or silicate solutions produces insoluble compounds in the pores.
8. **Pointing with good mortar**, and cleaning to remove algae and salts.
9. **Regular maintenance** and cleaning with water or brushes.

## Check yourself

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

1. Which stone is best selected to resist deterioration?
   A. Highly porous stone
   B. Freshly quarried stone with sap
   C. Dense and low-porosity stone, seasoned
   D. Soft stratified stone
   Answer: C. Dense low-porosity seasoned stone resists water and weathering. (Key point: Selection)

2. Which is used as a solution treatment to preserve stone?
   A. Sulphuric acid
   B. Plain lime water only
   C. Caustic soda
   D. Baryta water or alum and soap solution
   Answer: D. Baryta water and alum-soap solutions fill and seal pores. (Key point: Surface treatment)

3. How should stratified stone be placed for preservation?
   A. Natural bed perpendicular to load, with a drip course on projections
   B. Natural bed parallel to load
   C. Bed vertical in cornices only for decoration
   D. Bed horizontal in arches
   Answer: A. Correct bed placement and drip courses protect stone from water and splitting. (Key point: Placing)

## Related in Civil Engineering Materials

- [Deterioration and preservation of stone](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Adeterioration-preservation-stone) — Civil Engineering Materials, chapter 2, asked 2×
- [Causes of deterioration of stone](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Acauses-deterioration-stone) — Civil Engineering Materials, chapter 2, asked 4×