Today we are going to discuss about damp proof course. It is also known as DPC.
Table of Contents
What is Damp Proof Course (DPC)?
Damp proof course resists the movement of moisture through walls and floors. This types of coating normally applied at basement level.
A damp proof course (DPC) is a layer of material installed in a building’s walls or floors to prevent moisture from rising through the building structure.
Types Of Damp Proof Course
The following are the different types of damp proof course:
1. Physical DPC:
This type of DPC is made of materials that create a physical barrier against moisture. Examples include slate, bitumen, and plastic sheeting.
2. Chemical DPC:
This type of DPC is created by injecting a liquid or cream chemical into the walls or floors, which forms a barrier against moisture. Common chemical DPC materials include silane, silicone, and polysiloxane.
3. Electro-osmotic DPC:
This type of DPC uses an electrical current to repel moisture from the building structure. This is typically used for low-level damp problems.
4. Cavity wall DPC:
This type of DPC is created by installing a membrane between the inner and outer walls of a cavity wall. This prevents moisture from penetrating the building structure.
5. Basement tanking DPC:
This type of DPC is used to prevent moisture from entering basements or cellars. It involves applying a waterproof coating to the walls and floors of the basement.
6. Injection DPC:
This type of DPC is created by injecting a chemical solution into the walls or floors to create a barrier against moisture. It is typically used for older buildings that do not have a DPC installed.
How To Apply DPC
Dampness in walls can be a persistent and frustrating problem for homeowners. A damp-proof course (DPC) is a barrier installed within the walls to prevent moisture from rising through the walls and causing damage to the building. Applying a damp-proof course is a specialized task that requires the expertise of a trained professional.
Here is a general overview of the process:
- Remove Salt Contaminated Plaster: The first step in applying a DPC is to remove any contaminated plaster that may be present on the walls. This is important as it ensures that the DPC will be applied to a clean and sound surface.
- Drill Holes: The next step is to drill 12mm holes into the wall at least 150mm above the ground level. The holes should be spaced at regular intervals to ensure even distribution of the DPC. The number and spacing of the holes will depend on the thickness of the wall and the degree of dampness present.
- Install Damp-proof Course: The injection cream is then inserted into the holes, using a special injection gun. The cream is designed to spread throughout the wall and create a barrier against moisture. Once the holes are full, they will be capped with either mortar or plastic plugs.
- Apply Scratch Coat: A rough coat of at least 5mm thick should be applied to the wall after the DPC has been installed. This will act as an anchoring layer for the plaster coat.
- Apply Plaster Coat: Once the scratch coat has become firm, apply the plaster again with at least 15mm-20mm thick. The thickness of the plaster coat will depend on the condition of the wall and the desired finish.
- Finishing Coat: Apply a final skim coat using suitable skim plaster. This will provide a smooth finish to the wall surface.
It is important to note that the above process is a general guide and the actual process may vary depending on the specific requirements of the project.
It is always advisable to seek the advice of a trained professional before attempting to apply a damp-proof course. Additionally, it is important to use high-quality materials and tools to ensure the effectiveness and longevity of the DPC
FAQS
A damp proof course, or DPC, is a layer of material – typically a waterproof barrier like plastic or bitumen – that is installed within a building’s walls or floors to prevent moisture from seeping into the structure. This helps to prevent rising damp and related issues like mold growth and rot.
The main types of damp proof course are physical, chemical, and electronic. Physical DPCs are barriers installed between the structure and the damp ground, while chemical DPCs involve injecting a water-repellent substance into the walls to create a barrier. Electronic DPCs, on the other hand, use an electrical system with anodes to prevent moisture from seeping into the walls.
A damp proof course is usually installed at the base of a building’s walls, just above ground level. However, it may also be installed in floors, around windows and doorways, and in other areas where moisture could potentially enter the structure.