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Correct option is (a) 10°

Best explanation: Flat roof is the TYPE of roof that has slope less than 10°. Flat roofs are USED as a terrace for playing, GARDENING etc. The METHOD of construction and maintenance of flat roofs is relatively easy.

Correct answer is (a) Gauge = (LENGTH of slate – lap)/2

Best explanation: In slate roofing, the slates are FIXED to the BATTENS. The spacing of these battens is known as gauge. Gauge is calculated by USING the FORMULA – Gauge = (length of slate – lap)/2.

The correct choice is (B) Magnesia, SILICA

The best explanation: White asbestos is a COMPOUND of magnesia and silica. It is the most often used form of asbestos. It is used in the roofs and CEILINGS of industrial buildings and even residential buildings.

Right option is (C) 3 metres

For explanation: In trussed roofs, the limit of the spacing for wooden TRUSSES is generally 3 metres. Trussed roofs are used when the span of the ROOF is greater than 5 m.

The correct option is (b) Purlins

Explanation: When the SPAN exceeds about 2.4 meters, the necessary size for the rafters become ECONOMICAL. Hence double or Purlin roofs are provided in such CASES.

The correct answer is (C) Dome

Explanation: The Dome is useful 1 rupees to be provided on a CIRCULAR brickwork or regular POLYGON shape walls. The curved roof afford pleasing appearance in most of the cases, the construction of CURVES result in the economy of Steel and concrete.

The correct option is (b) FLAT roofs

The best I can EXPLAIN: Flat roofs are used in hot regions or in the areas having MODERATE rainfall and no snowfall. They are used for the BUILDINGS in plain areas.

Right choice is (b) 8 KG

Easiest explanation: 8 kg of bhusa per m^3 of CLAY is USED to PREPARE mud-phuska. Mud-phuska terracing with tile paving is the type of terracing that is equally suitable to hot as well as arid places.

Right option is (d) They require less area of roofing material

The explanation: Some of the DISADVANTAGES of FLAT ROOFS are they are not appropriate at places of heavy rainfall, their self-weight is very high, and LOCATION and rectification of a LEAK in a flat roof is difficult. However, the requirement of a lesser area of roofing material in flat roofs is an advantage.

Right choice is (B) Over tile

Easy explanation: The FIGURE GIVEN above REPRESENTS over tile. In this figure, A represents the HEAD and B represents the tail. An over tile tapers down from the tail to head while an under-tile tapers down from the head to tail.

Right option is (a) True

The best I can explain: Steel roof truss is designed in such a way that it carries only direct STRESSES and not binding stresses. Direct stresses can be either COMPRESSIVE or tensile. Steel roof TRUSSES are usually made of angle SECTIONS and PLATES.

Right option is (b) Timber

For EXPLANATION: Asbestos-cement sheets are made of asbestos, FIBRE and portland cement. They consist of NEARLY 15% fibre. Nowadays, asbestos cement is widely used in the manufacturing of ROOFING slates and tiles.

Correct choice is (a) Everest small-seven CORRUGATED A.C. SHEETS

Explanation: Asbestos cement roof COVERINGS come in three TYPES in India. These are Everest big-six corrugated A.C. sheets, Everest standard corrugated A.C. sheets and Everest TRAFFORD A.C. sheets.

The correct ANSWER is (a) TIMBER and steel

To explain I would SAY: COMPOSITE roof trusses are made of timber and steel. In this TYPE of truss, timber is used to make the compression members while steel is used to make the tension members.

Correct choice is (c) Cleats

Best EXPLANATION: In a king-post TRUSS, cleats PREVENT the purling from tilting. These are FIXED on the principal rafters. Purlins are placed at right angles to the sloping principal rafters. These purlins are made of stout timber.

The correct choice is (C) Purlins

Explanation: There are basically three elements in trussed roofs. These are rafters, purlins and trusses. The FUNCTION of the trusses is to provide support to the purlins which in turn provide support to the rafters. Rafters are USED to provide support to the ROOFING material.

The correct CHOICE is (b) Two

The explanation is: There are BASICALLY two elements in a double roof. These are rafters and PURLINS. The purlins PROVIDE intermediate support to the rafters.

The correct answer is (c) They are non-combustible

Easiest explanation: Thatch roof COVERING is widely used in villages because of its LESS cost. They are very light and are not STABLE against winds. They are LIKELY to decay EASILY and are highly combustible.

Correct answer is (b) Flat roof

To explain: The Flat roof must slope in one DIRECTION or the other to cause rain water to flow of rapidly and easily. The construction of the flat ROOFS is same as that of floor except that the top SURFACE is made slightly sloping in CASE of flat roofs.

Correct answer is (b) Queen-post

The explanation: In the queen-post truss, the joint at the head is formed due to the JUNCTION of TWO COMPRESSION MEMBERS and one tension member. The two compression members are principal rafter and straining beam and the tension member is the queen-post.

Correct answer is (a) Two

The best explanation: There are two VERTICAL posts in a QUEEN-post truss, unlike a king-post truss which has only one vertical post. These two vertical posts in a queen-post truss are KNOWN as queen posts. The TOPS of these queen posts are connected by a horizontal member known as a straining beam.

The correct option is (B) King rod

The explanation is: The above figure shows a close COUPLE roof. In this figure, A REPRESENTS ridge piece, B represents king POST, C represents rafter and D represents tie beam.A king post is a vertical rod placed at the centre which JOINS the ridge piece and the tie beam.

Correct option is (c) Double tiled

To explain I WOULD SAY: An overlap of at least 18 mm should be provided when country tiles are used. These tiles are LIABLE to BREAK EASILY and hence they require frequent replacement.

The correct choice is (c) Rise to span

To explain I would say: PITCH is EXPRESSED as a ratio of rise to span. Span is the DISTANCE between the SUPPORTS of an arch or beam. Rise is the vertical distance measured between the WALL plate and the top of the ridge.

Right option is (d) COUPLE

The best explanation: In Couple ROOFS, the common RAFTERS are firmly secured in POSITION at both the ends, one in being on the ridge piece and the other on the wall plate. Such a roof is not very much favoured because it has the TENDENCY to spread out at the feet.

Right choice is (d) Queen post truss

Explanation: A Queen post Truss roof is SUITABLE for roof of span varying from 8 METERS to 12 meters. A straining sill is INTRODUCED under tie beam known as a straining beam, between the queen post to counteract the THRUST of struds.

Right choice is (b) Gable roof

To explain: Sloping TRIANGLES are formed in the hip roof at the end faces while in the MANSARD roof, sloping ends are obtained. Mansard roof also slopes in FOUR directions just like hip roof but the difference is that in mansard roof, each slope has a break. At the end of the hip roof, the sloped triangular surface formed is known as the hipped end.

Right choice is (b) Battens

The BEST explanation: Barge BOARDS are the wooden PLANKS or boards which are fixed on the gable ends of a roof. They CONNECT the ends of the RIDGE, Purlins and wall plates.

Correct answer is (b) Jack Rafter

To explain I would say: COMMON RAFTERS are the intermediate drafters that give support to the ROOF covering. WHEREAS, hip rafter are the rafters which are provided at the junction of TWO roof slopes.

Right CHOICE is (d) Purlins

To explain: Whereas, RAFTERS are the pieces of TIMBER which extend from the Eaves to the ridge. COMMON rafters, Hip rafters, JACK Rafter, principal rafters are the various types of rafters.

The correct answer is (c) 25 mm, 25 mm

Easy EXPLANATION: EAVES board is a wooden board which is fixed to the FEET of the common rafters at the eaves. The thickness and the WIDTH of an eaves board are GENERALLY 25 mm and 25 mm respectively.

Right option is (b) Galvanized iron

Easiest explanation: The PROCESS of galvanising is name after the 18^th century Italian scientist GALVANI and it has been prepared to highly sophisticated degree achieving improvement in the quality, economic, productivity and labour savings. The corrugation help to INCREASE strength and RIGIDITY and the permit easy flow of RAINWATER.

Correct answer is (c) King-post roof truss

For explanation: 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.

Correct OPTION is (d) LEAN on roof

The best I can explain: In Lean-on roofs, one wall is carried up sufficiently higher than the other one to give necessary look to the roof. The RAFTERS are suitably SECURED on the wall plates and eave boards, BATTENS and roof covering are provided.

Correct answer is (d) Manganese

The explanation is: ALUMINIUM ROOF sheeting is the lightest of all the roofing MATERIALS. It consists of aluminium ALLOYED with manganese. Manganese is present in a very small amount to impart STRENGTH.

Correct OPTION is (d) King-post TRUSSES

For explanation I would SAY: The VARIOUS categories of steel trusses are open trusses, north light trusses, bowstring trusses and arched rib trusses. King-post trusses are wooden trusses.

Correct answer is (a) 3.6 metres

The explanation is: 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.

Right option is (B) Patent

Easy explanation: Mangalore tiles are RED in colour and made of DOUBLE channel mission Mangalore pattern. The special Mangalore tiles are available for ridge. It is found that about 14 Mangalore tiles are required for COVERING 1 square metre of roof area.

Correct ANSWER is (c) Couple-close

Explanation: In Couple-close beam, the TIE beam prevents the tendency of rafter to spread out and THUS the danger of overturning of the wall is AVOIDED. The tie beam can also be used as a CEILING joists when required.

Correct answer is (d) DRAGON beam

The best I can explain: The lower end of a hip rafter is generally SUPPORTED on a diagonal piece of WOOD which is lead across the corner of the wall. This diagonal piece is known as the Dragon beam or a dragon TIE or an ANGLE tie.

Right option is (a) Roof

Easiest EXPLANATION: A roof basically consists of structural element PROVIDED at the top of building from the support of roof coverings. The structural element MAYBE trusses, portals, SLABS, domes, etc. and the roof covering maybe AC sheets, GI sheets, etc.

Correct answer is (d) Tiles

The best explanation: In PUNJAB, mud terracing is done on tiles. In this, well burnt tiles of SIZE 30 cm X 30 cm x 5 cm or 30 cm x 15 cm x 5 cm are generally USED. However, in Madhya PRADESH and Maharashtra, mud terracing is done on wood boards.

The correct answer is (d) Half-round COUNTRY TILES

To explain: Half-round country tiles are laid in pairs of over-tiles and under-tiles. The under-tiles are laid with the concave SURFACE UPWARDS and the over-tiles are laid with the convex surface upwards. These tiles are SIMILAR to Spanish tiles.

The correct answer is (b) Template

For EXPLANATION I would SAY: Templates helps in SPREADING the load over a LARGE AREA. A template may be of wood or stone or RCC.