Which of the following materials is used for waterproofing during the construction of a foundation and for protecting the structure from seepage problems?
Try it first: pick an option, then read the explanation.
Asked in SSC JE 06/06/2024 (Morning)
Detailed Explanation
Foundations and basement walls are in contact with damp soil and sometimes with groundwater. A waterproof layer is needed to stop water rising into walls (dampness) or seeping through into the structure.
Why “Pitch” Is Correct
Pitch is a black, sticky, bituminous material obtained from tar or petroleum. It does not absorb water and sticks well to masonry and concrete, so it is applied hot as a coating on foundation surfaces and used in damp-proof courses to form a water barrier.
Why the Other Options Are Wrong
- A. Plaster of Paris: Plaster of Paris absorbs water and weakens when wet, so it cannot waterproof.
- C. Portland cement: Portland cement is a binder; ordinary cement concrete is not a waterproof membrane by itself.
- D. Furnace slag: Furnace slag is used in slag cement and as aggregate, not as a waterproof coating.
Key Point
Bituminous materials (pitch, bitumen, asphalt) are the classic waterproofing for foundations and DPC.
Key Concepts for Students
- A damp-proof course (DPC) is laid at plinth level to stop rising dampness.
- Bitumen felt and polythene sheets are other DPC materials.
- Tanking is waterproofing of basements below the water table.
Practice more: this is question 5 in Shallow and Deep Foundation MCQs – Part 1. Try the whole set and check every answer instantly.