Question

The different parts of a parapet wall and terrace section are labelled as P, Q, R, S, T. Which of the following is/are correct?

• A. P - Coping, R - Lime terracing, S - Rainwater pipe
• B. Q - Drip course, S - Rainwater pipe, T - Roof slab
• C. P - Vent pipe, Q - Drip course, R - Roof slab
• D. P - Vent pipe, R - Rainwater pipe, T - Roof slab

Hint:

Work top to bottom on the parapet section: P = coping, Q = drip course, then the terrace build-up (R = lime terracing over T = roof slab), and S = rainwater pipe at the outlet.

Answer 1

The Correct Option is A, B

Step 1: Read the parapet cross-section.
The figure is a vertical section through the edge of a flat roof, where a low parapet wall rises above the terrace. Reading it from top to bottom: P sits at the very top of the wall, on the projecting cap; Q sits just below P, still on the face of the parapet wall; T and R point into the layers of the terrace itself, and S sits at the outer corner where the terrace meets the parapet, near a pipe bend.

Step 2: Identify P and Q.
The topmost projecting, sloped element that throws rainwater clear of the wall face is the coping, so P is Coping. Just beneath the coping, a small groove or projection is normally provided on the underside so water does not creep back and run down the wall; this is the drip course, so Q is Drip course.

Step 3: Identify R and T.
On a flat roof, above the structural roof slab there is a graded layer, usually lime concrete or mud phuska, laid to a fall to drain rainwater towards the outlets; this is the lime terracing, matching arrow R. Below this terracing layer sits the load-bearing reinforced concrete roof slab itself, matching the deeper arrow T.

Step 4: Identify S.
At the parapet-terrace junction, a pipe with a bent profile carries collected rainwater down and away from the roof; this is the rainwater pipe, so S is Rainwater pipe.

Step 5: Test each option.
Option (A) says P - Coping, R - Lime terracing, S - Rainwater pipe, which all match Steps 2 to 4, so (A) is correct. Option (B) says Q - Drip course, S - Rainwater pipe, T - Roof slab, which also all match, so (B) is correct. Options (C) and (D) both call P a Vent pipe, but P is the coping at the top of the wall, not a vent pipe, so both (C) and (D) are wrong.

Final Answer:
Only options (A) and (B) describe the labelled parts correctly.
\[ \boxed{\text{(A) and (B)}} \]