Mastic asphalt in buildings — Typical uses in building envelopes and protection layers

Introduction / Context:Mastic asphalt is a dense, void-less bituminous mix. In building construction, it is prized for its impermeability and durability, making it ideal for horizontal barriers against moisture ingress and water ponding.

Given Data / Assumptions:

• Usage pertains to building envelope layers.
• Performance sought: watertightness and damp proofing.

Concept / Approach:Because mastic asphalt is practically impervious and forms a monolithic layer, it is widely used as a DPC above plinth level and as a waterproofing membrane for flat roofs, balconies, and wet areas. It is not a loadbearing masonry material for partition walls.

Step-by-Step Solution:Identify functions: moisture barrier and waterproofing.Map to locations: DPC at walls; horizontal roof membranes.Exclude non-relevant structural use: not used as partition wall material.

Verification / Alternative check:Common specifications list mastic asphalt for DPCs and roof waterproofing details including overlaps and protective screeds.

Why Other Options Are Wrong:Partition walls: typically brick, block, or drywall systems; mastic asphalt is a membrane, not a wall unit.Sound insulation only: not the primary purpose, though mass can aid acoustics secondarily.

Common Pitfalls:Confusing mastic asphalt with asphalt concrete; mix design and use cases differ.

Final Answer:Both (a) and (b)