Damp Proofing

Damp proofing or a Damp-Proof is a type of moisture control that is either hand applied on the exterior wall or sprayed onto the wall and floors to prevent moisture from passing into the interior spaces, it reduces the rate of moisture absorption.

Moisture resistance must not be absolute, it is defined by a specific test method, range and engineering tolerance.

Here we will learn about damp proofing, methods of damp proofing & how do you damp proof a wall?

Introduction to damp proofing:

Damp proofing is a type of moisture control applied to walls, residential floors or commercial buildings to prevent moisture, mold and moisture.

Damp proofing problems are one of the most frequent problems occurring in homes these days; they occur mainly in old buildings or poorly constructed buildings.

Frequently damp proofing products keep the moisture away from the buildings, where vapor barriers retain internal moisture to the walls.

Causes of damp proofing in roofs:

  • It makes the poor quality of construction material.
  • It has a bad design.
  • Fault in construction.
  • The rainwater falling on the outer walls & parapet causes moisture.
  • If the roof of low quality, rainwater can also enter into the house.
  • Small roof slopes or faulty junctions between roof slabs and parapet walls can cause damping.
  • Leakage through down passes can cause moisture.

Methods of damp proofing:

1.Damp-Proof Course (DPC):

Damp Proof Course is a wall through the structure by stripe action known as rising damp, it is the effect of water rising from the ground to the building.

Some problems involves salt damp, lateral damp, rising damp & mould.

There is some damp proof course that makes damp proofing problems could not occur again.

2.Cavity walls:

A cavity wall consists of two parallel walls/masonry skins, separated by a continuous air space.

It consists of three parts: outer wall/leaf (10 cm thick of outer wall), cavity/air space (5 cm-8 cm), and inner wall/leaf (minimum 10 cm thick).

The two leaves forming a cavity in the middle or may not be of the same thickness.

The provision of continuous cavity walls efficiently prevents the transmission of moisture from the outer to the inner wall.

Under India’s climatic conditions (hot-dry / hot-humid), cavity type construction is most desirable.

As, it has many advantages such as better living and resting conditions, occupational structure, and protection of buildings against moisture.

3.Shot Concrete (Gunting):

It consists of forming an impermeable layer of enriched cement mortar (1: 3) for damp proofing on the exposed concrete surface to withstand water pressure.

Gunning is a mixture of cement and sand with the usual ratio of 1: 3 or 1: 4.

A machine is known as a cement gun which has a nozzle for spraying the mixture and a drum of compressed air to force the mix under the desired pressure.

Any surface to a given treatment is first thoroughly cleaned with any dirt, oil, or loose particles and then thoroughly wetted.

A mixture of cement and sand provided with a pressure of 2-3 kg / sq. cm. by holding the tip of the cement gun at a distance of 75–99 cm from the wall surface.

The impermeable surface should be sprinkle with water for 10 days.

4.Silicone Damp Course:

Silicon is primarily a wax with highly effective water-repellent properties, and in damp proofing course, fluids dissolved in a spirit base with anti-fungal components.

5.Plastering Work:

Plastering work is a process to change the composition of the plaster, making it more likely to attract and retain moisture.

6.Sub-floor ventilation:

Sub-floor ventilation is to exchange moist air with fresh air.

7.Fixing Skirting Board:

A damp, rotting skirting board or floor to get rid of growing damp proofing problems.


Drainage is the natural or synthetic removal of floor and sub-surface water from a space.

Advantages and Disadvantages of damp proofing:


  1. The use of cement leads to a better water system.
  2. It gives the roof a reasonable slope.
  3. It is durable and sustainable.
  4. It repairs other voids or cracks that are already present in roof slabs.


  1. Normal cracks sometimes develop in this damp proofing process.
  2. Also, it provides additional weight to the entire structure.
  3. It leads to the level problem.
  4. Sometimes it creates ugly patches up to the roof.
Also read: Waterproofing, Papercrete & Admixture


Damp proof works as longterm prevention of moisture decay.

When it comes to walls and foundations, damp proofing prevents moisture and water from passing through interior spaces.

Hello, I'm Rahul Patil founder of Constructionor.com, I had studied B.E. Civil. This blog provides authentic information regarding civil structures, equipment, materials, tests & much more.

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