Building Construction Multiple Choice Questions & Answers (MCQs) on “Single and Double Roofs”.
1. Which of the following is not a type of single roof?
a) Lean-to-roof
b) Couple roof
c) King-post roof truss
d) Collar beam roof
Answer: c
Clarification: There are five types of single roofs. These are lean-to-roof, couple roof, couple close roof, collar beam roof and collar and scissors roof. Single roofs consist of only the rafters which are supported at the ridge and the wall plate.
2. _________ joint is used to connect the wooden tie and the feet of rafters in a couple of close roof.
a) Dovetail halved
b) Closed mortised and tenoned
c) Pin and tenoned
d) Open and pin
Answer: a
Clarification: Dovetail halved joint is used to connect wooden tie and the feet of rafters in a couple of close roof. In a couple close roof, the ends of the couple of common rafters are connected a tie beam. It is used to prevent the rafters from spreading out of the wall.
3. A couple roof is suitable for spans up to _________
a) 3.6 metres
b) 4.2 metres
c) 5.6 metres
d) 6.3 metres
Answer: a
Clarification: A couple roof is suitable for spans up to 3.6 metres. This type of roof has a great tendency to spread out at the wall plate level. However, a couple close roof is usually used when the span is limited to 4.2 metres.
4. Which of the following is also known as a pent roof?
a) Lean-to-roof
b) Couple roof
c) Couple-close roof
d) Collar beam roof
Answer: a
Clarification: Lean-to-roof is also known as a pent roof. It is also known as the aisle roof. Lean-to-roof is the simplest type of sloping roof. In this, rafters’ slope to one side only.
5. How many elements are generally there in a double roof?
a) One
b) Two
c) Three
d) Four
Answer: b
Clarification: There are basically two elements in a double roof. These are rafters and purlins. The purlins provide intermediate support to the rafters.
6. Triple-membered roofs are also known as _______
a) Verandah roofs
b) Collar tie roofs
c) Purlin roofs
d) Trussed roofs
Answer: d
Clarification: Triple-membered roofs are also known as trussed roofs. A triple-membered roof is used when the length of the room is large and the span of the room exceeds 5 metres.
7. Which of the following roof is also known as rafter roof?
a) Double roof
b) Lean-to-roof
c) Couple-close roof
d) Couple roof
Answer: a
Clarification: Double roof is also known as rafter roof or purlin roof. Double roofs are used when the span exceeds 5 metres. Purlin is used to tie the rafters together.
8. Lean-to-roof is suitable for maximum span of ______
a) 1.3 metres
b) 2.5 metres
c) 3.6 metres
d) 4.2 metres
Answer: b
Clarification: Lean-to-roof is suitable for a maximum span of 2.5 metres. These types of roofs are generally used for sheds, verandahs etc. Hence, they can also be called verandah roofs.
9. The central vertical rod provided in the couple close roofs is called as ________
a) King rod
b) Queen post
c) King post
d) Queen stone