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Correct answer is (a) CRACKING

For explanation: Development of fissures in the PLASTER DUE to the movement of the background results in a phenomenon CALLED cracking. Any kind of vibrations or movements in the surrounding structures can ALSO cause cracking.

Correct option is (b) Efflorescence

Easiest explanation: Due to Efflorescence, the SOLUBLE SALTS are PRESENT in plaster MAKING materials as well as building material such as bricks, sand, cement, etc. Even Water used in the construction work may contain soluble salt. When a newly constructed wall dries out, the soluble salts are brought to the surface and they appear in the form of white is a crystalline substance.

Right option is (a) 3 MM

Easiest explanation: A devil float is a TOOL used to MAKE zigzag lines on the plastered surface in order to FORM a key. It has a NAIL projection of about 3 mm from the surface.

Right answer is (a) Peeling

To ELABORATE: Dislodgement of plaster from the BACKGROUND is called peeling. Peeling involves the COMPLETE DISLOCATION of some part of the plastered surface which RESULTS in the formation of a patch.

Correct choice is (C) Cement mortar

The best explanation: In cement mortar, the materials are thoroughly MIXED in a dry condition before water is added to them. The mixing of material is DONE on the watertight platform and the mortar of one cement bag only is prepared at a time and this quantity of mortar is consumed within 30 minutes after adding water.

Right answer is (d) Textured FINISH

Easiest explanation: Textured finish is used with STUCCO PLASTERING. In this, suitable tools are used to make ORNAMENTAL patterns on the final COAT of stucco plastering.

The correct option is (c) Laitance

Explanation: The thin layer of cement particles FORMED on excessive troweling of freshly laid mortar is called laitance. This layer CONSISTS of FINE cement particles.

The correct option is (a) True

The explanation: In smooth cast FINISH, steel floats are not recommended for external RENDERINGS. Instead, a wooden float is used for applying the mortar. This is because steel floats GIVE a very smooth finish which is very LIKELY to crack when EXPOSED to atmospheric conditions.

Correct CHOICE is (a) Dubbing

Easiest explanation: Dubbing is the process of filling the hollow spaces LEFT in the solid BACKGROUND. Dubbing is DONE before APPLYING the main body of the plaster.

Right answer is (c) DOTS

To explain I would say: Small PROJECTIONS of PLASTER that are laid on background for fixing of screeds are known as dots. The size of the dots is GENERALLY 15 cm x 15 cm.

Right answer is (a) ACOUSTIC Plaster

The EXPLANATION: The Acoustic Plastered surface is provided with minute openings that absorb the sound. The plaster is usually applied in TWO coats, each having a thickness of 6 mm. The finishing of the surface should be CARRIED out in a such a way that it results in the formation of UNIFORM porous surface.

Right answer is (d) PLUMB RULE

Easiest explanation: The GIVEN FIGURE represents the plumb rule. It is a tool which is used to check the verticality of WALLS.

The correct option is (a) Lime Mortar

For explanation: The fat lime is recommended for plaster work because the fat lime contains 75% of CaOH and it combines with CO2 of ATMOSPHERE and givesCaCO3 QUICKLY. THUS, the lime sets quickly, but it imparts low STRENGTH and hence it can be USED only for plaster work.

Correct choice is (a) Gauging trowel

Best explanation: The end of a gauging trowel can be either pointed or bull-nosed. It is used for gauging SMALL quantities of materials. It can also be used for SPREADING mortar on CORNERS, MOLDINGS, ETC.

The correct choice is (C) 1:3

Explanation: The mortar used for the SMOOTH cast finish has CEMENT and sand in the RATIO of 1:3. A smooth and levelled SURFACE is obtained in this finish.

Right ANSWER is (C) Asbestos marble plaster

The explanation: A beautiful marble like FINISH is obtained by using asbestos marble plaster. WHEREAS, for finishing work, Acoustic plaster is preferred to use wooden floats in PLACE of Steel floats.

The CORRECT ANSWER is (a) Struck

Easiest explanation: In Struck Pointing, the upper edge of the joint is about 10 mm inside the FACE of masonry. This joint disposes water easily. In the lower edge of the joint is kept inside the face of masonry. It is known as the OVERHEAD struck Pointing.

Right answer is (a) 1 : 3/2 : 3

Explanation: In rough cast finish, the mortar for the FINAL coat has the ratio 1 : 3/2 : 3 (CEMENT : sand : aggregate). Here, the size of the coarse aggregate varies from 3mm to 12 MM. A large trowel is used to dash the mortar against the prepared PLASTERED SURFACE.

Right answer is (a) Hacking

The BEST I can explain: Hacking is the PROCESS of roughening the BACKGROUND. Plastering is the method of covering rough surfaces with plaster in order to obtain an even and SMOOTH surface.

Right OPTION is (b) FLOATING RULE

The best I can explain: The given figure represents a floating rule. It is a TOOL which is used in the plastering work. Various other tools used in the plastering work are a metal float, a wooden float, gauging tools etc.

The CORRECT CHOICE is (b) Barium plaster

Explanation: Barium plaster is USED as a final coat for surfaces of X-Ray room so as to protect the person working in and around X-Ray ROOMS. It is essentially made from Barium sulphate.

The correct answer is (b) Tuck

The best I can explain: In Tuck pointing, the width and depth of GROOVE are respectively 5 mm and 3 mm. The groove is then filled in a tuck in by white cement putty with a projection of about 3 mm. If a projection is done in the MORTAR, it is called as BASTARD pointing.

Right ANSWER is (d) RECESSED

Explanation: The FACE of the pointing is kept vertical and it is pressed inside the wall surface by a suitable tool to a depth of about 5 MM or more. Recessed pointing use a very GOOD appearance.

Right answer is (C) Cement mortar

The best explanation: The cement should COMPLY with standard REQUIREMENTS and sand should be CLEAN, fine and free from any organic impurities. The material are thoroughly mixed in dry condition before water is added to them.

Correct choice is (a) HEMIHYDRATE Gypsum

The best EXPLANATION: On heating the hemihydrate gypsum, temperature of about 200°C, the ENTIRE water of crystallization is driven off and the RESULTING product is known as gypsum anhydride or hard burnt plaster. The setting time of the Gypsum anhydride is more and to shorten it,the accelerators ADDED to it.

The correct option is (d) WOODEN laths

The explanation is: In wooden LATH, the strips are generally 25 mm wide and 1 m to 1.20 m long. The length of strips are adjusted to suit the SPACING of timber joists. ACCORDING to thickness, the wooden strips are classified into THREE categories.

Right answer is (a) 7

To explain I would say: Sand faced finish is acquired by plastering in two coats. The SECOND coat of plaster is APPLIED after curing the first coat for 7 days. The surface of the final coat is finished by rubbing clean sand of UNIFORM size.

Correct choice is (b) False

Easy explanation: Undercoat is the COAT of PLASTER applied under the setting coat. The setting coat is the final coat of plaster which is also known as the FINISHING coat.

Correct choice is (B) False

The EXPLANATION is: The lower part of the plastered WALL is dado. It is applied for a height of 3-7 feet especially in toilets, kitchens etc. to prevent WATER absorption and to MAKE the walls smooth.

The correct option is (b) Metal lath

Easy explanation: Metal lath is prepared from SHEETS of MILD steel which are machine cut and drawn out or expanded. A diamond mesh appearance is thus formed throughout the whole area of the sheet. The hybrid which is steel lath can ALSO be USED for this purpose.

Right CHOICE is (c) Crazing

Easiest explanation: DEVELOPMENT of hair cracks in the plastered SURFACE is known as crazing. The cracks are made usually in irregular patterns over the finished plastered surface.

The correct choice is (c) Sirapite

The best explanation: Sirapite is quickly setting material and produces hard white surface on DRYING. It is also a better fire resistant material. Thistle hardwall is a product of high grade gypsum and it POSSESSES a high CAPACITY to CARRY SAND.

The correct ANSWER is (b) SCAGLIOLA

Easiest explanation: Scagliola appears like marble and is used for pilasters, PANELS, etc. Whereas, Sirapite is obtained when plaster of Paris is slaked in petroleum. It is a quick setting and produces a hard WHITE surface on drying.

Right answer is (c) Peeling

For explanation I WOULD SAY: The PLASTER from some portion of the surfaces comes off and a PATCH is formed. Such formation is termed as the Peeling and it is ALSO mainly due to Bond failure between successive coats of plaster.

Correct answer is (B) Crazing

Best explanation: Cracks are formed on the PLASTERED SURFACE and may be hair cracks or cracks which may be easily SEEN.

The CORRECT answer is (C) POINTING

Best explanation: The process of pointing is adopted for STONE masonry or brick masonry wall plastering is carried out for expose surfaces of ceiling, walls, column, etc.

Right choice is (a) Pearl ash

Best explanation: Martin’s cement plaster is OBTAINED when pearl ash is CALCINED with POP. It has quick SETTING properties and is USED in INTERNAL finishing works.

Correct answer is (b) GROUNDS

Explanation: Wooden strips FIXED to the surface on which first coat of PLASTER is applied are called grounds. Such a surface is called background. The function of these strips is to secure the primary finishing.

The correct option is (C) Gauging

The EXPLANATION is: The mixing of different constituents of plaster is known as gauging. A GOOD plaster should be such that it REMAINS adhered to the background during all SEASONS. A good plaster should be hard and durable.

Right option is (B) SOFTNESS

For explanation: The chief REASON of such softness are due to thickness of the finishing coat, presence of deliquescent salts, excessive suction of the undercoat, ETC. Hence, this LEADS to excessive dampness at certain points on the plastered surface makes that portion Soft.

The correct answer is (c) Wooden laths

Best EXPLANATION: Wooden laths are also likely to be attacked and DAMAGED by the WHITE and fungi. The thicker strips are useful for CEILINGS where STRAIN is more and thinner strips are used for walls and partitions where strain is comparatively less.

The correct choice is (a) METAL laths

Explanation: The metal laths PROVIDED a better fire resistance construction in FORM of FIRM and solid foundation for plaster work. The various TYPES of metal laths under patent names are available in the market. The ribs in the metal lath renders stiffness to the Steel sheet.

Right choice is (c) Skimming float

To explain: A float provided with NAILS PROJECTING by about 3 mm from the SURFACE is known as the Devil float and it is used to make Zig ZAG lines on the plastered surface so as to form a key for the subsequent coat.