Damp Proof Course in Construction: Types, Materials, Application, and Benefits

What Is Damp Proof Course?

The damp proof course is an important layer for all walls of the building that is provided near the ground in the wall to prevent dampness of the walls.

In the properties of which there has no provided damp protection layer, that may be affected by excess moisture rising from the ground. This excess moisture can affect decoration, plaster, and even wet rot or effecting unprotected timbers.

A damp proof course minimum of 150 mm should be provided above the walls in most properties. As a mortar course with plastic DPC sheet or bitumen may appear by poking through.

To prevent rising damp from occurring in all new properties the damp proof course is required. To avoid the dampness in the properties at first we have to inspect the properties by a specialist damp surveyor.

DPC Full Form

The full form of DPC, in civil engineering, is Damp Proof Course. It normally provides near the ground in the wall to prevent dampness in the.

DPC History

In London in the year 1975, the DPC or damp proof course became mandatory. A solid layer of DPC is built and provide in the walls of the constructions and placed above the ground level so through the capillary action the moisture rising over the wall should be prevented.

The dampness problem makes your interior or exterior walls fade and it is looking so unnatural. The material used in 1975 as DPC is –jute, bitumen, hessian, and slate. Above them, the slate layer is the most useable material at that time.

Types of Damp Proofing Course

Many types of damp proof course’s are below

1. Hot Bitumen

The hot bitumen type of damp proofing course is a flexible material that is placed on the mortar or the concrete bed. The hot bitumen course at least with a minimum thickness of 3mm should be applied.

2. Bituminous Felts

The bituminous felt also flexible material. It is easy to available in the rolls of normal wall width and easily lay. On a cement mortar, it can easily be laid.

At the all corner full overlap is provided and at the joints of the overlap 100 mm is provided. If necessary the laps are sealed with bituminous. The bituminous felts materials are available in rolls, so especially in cold weather, they should be unrolled carefully.

3. Metal Sheets

The metal sheets are also flexible material. The damp proof course provides copper and aluminum. The weight of the metal should not be less than 200 N/m² and the thickness depend on this.

4. Mastic Asphalt

The mastic asphalt is a semi-rigid material and creates a good impervious layer as a damp proofing course. Mastic asphalt is a most durable and impervious material.

5. Stone

Slates, granites the two-course of a dense and sound stone laid in cement mortar with vertical breaking joint is work a great damp proof course. As in the case of roof surface sometimes the stone can be fixed.

6. Mortar

The mortar is used as a level course on the bed level and it is a ratio of the mixture of 1 part of cement and 3 part of sand. To increase the workability of the mortar some quantity lime is to be added. The waterproofing mortar should be prepared for the plastering works.

7. Cement Concrete

As a damp proof course, a cement concrete paste is provided in a ratio of 1:2:4 at the plinth area at the structure. The thickness of the cement concrete layer is varied between 40 to 150 mm. The cement concrete damp proof layer is a very effective material.

Damp Proof Course Material

There are four types of materials that are commonly used in

1. Flexible material.
2. Semi-rigid material.
3. Rigid material.
4. Grout materials. 

1. Flexible Material

Flexible materials are those materials that never deformed their shape and when a certain amount of load is applied they tend to crack, which is known as a flexible material.

2. Semi-Rigid Material

The combination materials or mastic asphalts are used as semi-rigid material.

3. Rigid Material

The rigid materials are stone, first-class bricks, cement concrete, slates, etc.

4. Grout Materials

The grout materials are consists polymers, cement slurry or acrylic-based chemical.

Application of Damp Proofing Course

1. The application of damp proof course is by this we can prevent all health issues that can see in the future on the structure.
2. It is applied to prevent the exterior wall moisture and protect from dampness.
3. The application of damp proof course is it helps to prevent dank and musty smell around the property that coming from the untreated mold.
4. The damp proof course is applied as an important layer for all walls of the building that is provided near the ground in the wall to prevent dampness of the walls.
5. To increase the paint life on the walls to remove the dampness by damp proof course. It is the most important application of damp proof course.
6. By the damp proofing course, we know the value and condition of the property.
7. To prevent the structural problems by the wet rot and dry rot the damp proof course is applied.
8. The concrete damp proof course generally applies to the water storage structure such as a damp, reservoir, etc.

Properties of Material for DPC

The properties of materials for DPC is

1. The most important property of DPC material is it should be impervious.
2. The second property of these materials is they should be enough durable and strong, or capable to withstand both live load as well as dead load without damage.
3. The properties of DPC material are its always be dimensionally stable.
4. To make the structure economical the material used for DPC should be cheap.
5. Another important property of the materials should be free from deliquescent salts like nitrates and sulfates chlorides.
6. The material should be able to carry out leakproof joining work.

Advantages of Damp Proofing Course

There have many advantages of damp proof course that’s are below

1. The first important advantage of a damp proof course is by this we can prevent all health issues that can see in the future on the structure.
2. The advantage of a damp proof course is it helps to prevent dank and musty smell around the property that coming from the untreated mold.
3. To increase the paint life on the walls to remove the dampness by damp proof course.
4. The concrete damp proof course is generally used at the water storage structure such as a damp, reservoir, etc. which is another advantage of a damp proof course.
5. By the damp proofing course, we know the value and condition of the property.
6. To prevent the structural problems by the wet rot and dry rot.

Disadvantages of Damp Proofing Course

1. The disadvantage of the damp proof course, in the damp proof course sometimes develops all cracks.
2. Another disadvantage of the damp proof course is it has level problems.
3. Up to the roof sometimes the damp proof course creates patches this is the disadvantage of the damp proof course.
4. The most common disadvantage of damp proof course is it increases the self-weight of the whole structure.

Uses of Damp Proofing Course

There have been many uses of damp proof course that are below

1. The important uses of a damp proof course are by this we can prevent all health issues that can see in the future on the structure.
2. The uses of damp proof course are it helps to prevent dank and musty smell around the property that comes from the untreated mold.
3. The damp proof course is an important layer for all walls of the building that is provided near the ground in the wall to prevent dampness of the walls.
4. The concrete damp proof course is generally used at the water storage structure clasp, reservoir, etc.
5. To increase the paint life on the walls to remove the dampness by damp proof course. It is the most important use of damp proof course.
6. By the damp proofing course, we know the value and condition of the property.
7. It is used to prevent the exterior wall moisture and protect from dampness.
8. To prevent the structural problems by the wet rot and dry rot the damp proof course is used.

Frequently asked questions (FAQs) that could be included in your article about damp proof course:

What is a damp proof course (DPC) in construction?

A damp proof course is a layer typically installed near ground level in walls to prevent rising dampness, which can otherwise damage building materials and affect structural integrity.

Why is a damp proof course necessary?

A DPC is essential to prevent moisture from rising through walls via capillary action, which can lead to damp patches, mold growth, and structural decay over time.

What materials are commonly used for damp proof courses?

Materials include bitumen, plastic sheets, metal sheets (such as copper or aluminum), mastic asphalt, stones like slate or granite, and various cementitious mixes.

How is a damp proof course installed?

Installation methods vary depending on the material used. Typically, DPC materials are laid in the mortar or concrete bed near ground level during the construction of walls.

What are the signs that a damp proof course is needed or has failed?

Signs include damp patches on walls, mold growth, musty odors, peeling paint or plaster, and visible salt deposits (efflorescence) on the wall surface.

Can an existing damp proof course be repaired or replaced?

Yes, if a DPC fails or is inadequate, it can be repaired or replaced. Methods include injecting chemical damp proofing agents or installing new physical barriers.

Are there different types of damp proof courses for different building materials or conditions?

Yes, the choice of DPC type depends on factors like building materials, environmental conditions, and the severity of damp issues. Different materials offer varying levels of flexibility, durability, and impermeability.

How effective is a damp proof course in preventing dampness in buildings?

When installed correctly and maintained, a DPC effectively prevents rising dampness, thus preserving the structural integrity of buildings and ensuring interior comfort and durability.

What are the long-term benefits of having a damp proof course?

Long-term benefits include reduced maintenance costs, prolonged lifespan of building materials, improved indoor air quality, and enhanced property value due to reduced damp-related issues.

Who should be contacted for installing or inspecting a damp proof course?

Qualified contractors or specialists in damp proofing should be contacted for installation, inspection, and maintenance of damp proof courses to ensure compliance with building regulations and standards.