Explanation: In simple reinforced cement concrete slab flooring, it is important to provide reinforcement in both the directions when the length of the room is 1.5 times its width. This is because in this case, the slab bends in both the directions and such a slab is called two-way reinforced slab.

Explanation: In simple R.C.C. floors, generally cement concrete of M20 mix is used. After pouring of the concrete, it is well-compacted and the slab is properly cured. Shuttering can be removed only when the concrete has fully been set.

Explanation: Bricks are classified into 3 types – first class bricks, second class bricks and third class bricks. Only first class bricks should be used in the construction of reinforced brick flooring. The size of the first class bricks is 19 cm x 9 cm x 9 cm.

Explanation: The beams used in beam-slab flooring are known as T-beams. In this type of flooring, the floor is comprised of R.C.C. beams and slabs cast monolithically. Beams serve as intermediate supports to the slab that is continuous over these beams.

Explanation: Ribbed floors are also known as hollow-tiled floors. In this type of flooring, hollow tiles replace the lower part of the slab since concrete cannot bear the tension caused in the lower part of the slab. The use of hollow tiles also reduces the weight of the slab.

Explanation: In ribbed flooring, the ribs are closely spaced and the clearing spacing of the ribs should not exceed 50 cm. It depends on the size of the hollow blocks available.

Explanation: In ribbed flooring, lateral ribs having the same width as that of longitudinal ribs are provided if the span exceeds 3 m. These are provided at intervals between 1-3 m.

Explanation: In ribbed flooring, the depth of the rib is at least L/20 with the free support. However, it is at least L/25 with fixed support. Here, L stands for the span of the ribs.

Explanation: Hollow-tiled floors are light in weight. They provide good thermal insulation, sound insulation and are fire-resistant.

Explanation: Cement mortar is used to fill the joints in precast concrete floors. Concrete guns are used for this purpose. The floors can be constructed very easily with the help of precast beam-slabs. These are generally available in 25 cm width.

Explanation: Timber floors are mainly of three types. These are – single joist timber floors, double joists timber floors and triple joists timber floors. These types of floors are light in weight and have poor fire resistance.

Explanation: Wooden joists provided in single joist timber floors are called bridging joists. the spacing between these joists is usually 30-40 cm and their width is generally kept 5-8 cm.

Explanation: In single joist timber floors, the depth of the joists is calculated using the formula – Depth = (4 x spanning metres) + 5 cm. Single joist timber floors are the simplest type of timber floors which are widely used for residential buildings.

Explanation: There are four elements of triple joists timber flooring. These are floorboards, bridging joists, girders and binders. Triple joists timber floors are also known as framed floors. This type of flooring is used for spans exceeding 7.5 m.

Explanation: The given figure shows single joist timber flooring. In this figure, A represents boarding, B represents wall plate and C represents bridging joist. A wall plate is a long wooden member which is provided on the top of the brick or stone wall.