A layer provided to prevent entry of unwanted moisture inside the building either by seepage or by leakage is known as
Damp proof course
Understanding Moisture Prevention in Buildings
Preventing unwanted moisture from entering a building is crucial for maintaining its structural integrity, indoor air quality, and comfort. Moisture entry can occur through various means, such as rain penetration, rising damp from the ground, or leakage through construction elements.
The Role of a Damp Proof Course
A specific layer is incorporated into the building structure specifically to block the passage of moisture. This layer acts as a barrier against moisture rising from the ground or entering horizontally through walls.
The term for this essential barrier is Damp Proof Course (DPC).
- A DPC is typically installed horizontally in walls, usually below the level of the lowest floor slab, to prevent moisture from rising through capillary action from the ground.
- It can also be installed vertically or horizontally in other parts of the building envelope to prevent moisture penetration.
- Common materials for a DPC include impervious materials like polythene sheeting, bitumen felt, mastic asphalt, or sometimes layers of slate or engineering bricks with waterproof mortar.
The primary function of the damp proof course is to create an impermeable layer that stops moisture from travelling upwards or inwards into the walls and thus into the building interior. This directly addresses the problem of unwanted moisture entry by seepage or leakage mentioned in the question.
Evaluating Other Options
Let's consider why the other options are not the primary answer for preventing general unwanted moisture entry by seepage or leakage:
- Roof: A roof is designed to protect the building from precipitation (rain and snow) from above. While crucial for preventing water ingress, it primarily deals with moisture coming from the sky, not necessarily seepage from the ground or leakage through lower wall sections which a DPC handles.
- Sunshade: A sunshade (or Chhajja) is an external projection over doors and windows designed to block direct sunlight. It has no function related to preventing moisture entry into the building structure itself, whether from the ground or walls.
- Lintel: A lintel is a structural element placed over openings like doors and windows to support the wall above. While it forms part of the building envelope, its function is structural support, not moisture prevention, although proper detailing around lintels is important for preventing localized water ingress.
Based on their primary functions, the damp proof course is specifically designed as a layer to prevent unwanted moisture entry by seepage or leakage into the building structure.
| Building Component | Primary Function | Moisture Prevention Role |
|---|---|---|
| Damp Proof Course (DPC) | Prevent moisture rising from ground/entering walls | Directly prevents unwanted moisture entry (seepage, rising damp) |
| Roof | Protect from rain/snow from above | Prevents precipitation ingress from top |
| Sunshade | Block sunlight | None |
| Lintel | Structural support over openings | None (structural) - detailing prevents localized leaks |
Revision Table: Moisture Prevention Layers
| Term | Purpose | Typical Location |
|---|---|---|
| Damp Proof Course (DPC) | Prevents moisture from rising from the ground or penetrating walls horizontally. | Horizontal layer in walls (usually near ground level), sometimes vertical/sloping. |
| Waterproofing Membrane | General term for barriers preventing water passage (can include DPCs). | Roofs, basements, wet areas (bathrooms), foundations. |
Additional Information on Damp Proofing
Proper installation of a damp proof course is critical for its effectiveness. Gaps or breaks in the DPC can allow moisture to bypass the barrier. In older buildings that lack a DPC, remedial damp proofing methods might be used, such as injecting chemical creams or inserting physical barriers.
Factors contributing to unwanted moisture entry can include:
- Porous building materials
- Poor drainage around the building
- High water table
- Defective plumbing
- Cracks or gaps in the structure
Implementing a robust damp proof course is a standard construction practice to mitigate the risks associated with ground moisture and external wall seepage, protecting the building fabric and internal environment.
Important Questions from Substructure
The portions of the structure below the ground level are called as
The process of marking the positions of various foundations and other elements on to the ground as per the drawings is called as
The structure which is used to divide the stages in different levels is termed as-
Temporary arrangement of boardings, wailings and struts which is provided to give support to sides of trench is known as___________.
Under which of the following types of the dampness-checking materials categories, does cement concrete fall?
