Waterproofing and damp-proofing — bitumen felt used in building construction is correctly described by which of the following statements?

Introduction / Context:
Bitumen felt (roofing felt) is a common membrane material in civil engineering for preventing water ingress through roofs, terraces, and walls. Understanding its composition and uses clarifies where it fits within a building’s moisture control strategy (waterproofing versus damp-proofing).

Given Data / Assumptions:

• Traditional felt uses a fibrous base (e.g., hessian/jute or fiberglass) saturated/impregnated with bitumen.
• Applications include membranes below screeds, on parapets, and as DPC courses.
• The question allows multiple correct descriptions.

Concept / Approach:

Bitumen felt is a composite sheet formed by saturating a fabric (historically hessian; modern versions may use polyester or glass mat) with bitumen, sometimes with mineral surfacing. It is used both for waterproofing (resisting liquid water under some hydrostatic pressure) and for damp-proofing (blocking capillary moisture without significant head), depending on grade, layers, and detailing. Thus, all statements collectively describe the material’s nature and uses.

Step-by-Step Solution:

Verification / Alternative check:

Standard specifications list bituminous felts for horizontal and vertical damp-proof courses and multi-ply roofing systems, validating all statements.

Why Other Options Are Wrong:

Choosing any single statement would omit key aspects of either use or composition; “all the above” is therefore accurate.

Common Pitfalls:

Assuming one-ply felt equals full waterproofing in all conditions; proper multi-ply build-ups and protection layers are essential for durability.

Final Answer:

all the above