MODULE 4 PART 1.pdf
- 1. Applied finishes - Wall finishes. Mortar & Plaster: Cement mortar, lime plaster and gypsum plaster. Fire resistant plaster, X-Ray shielding plaster and acoustic plaster. Plaster lath and accessories. Plaster over masonry and ceiling. Paints, Distempers and varnishes: Characteristics of an ideal paint. Classification – various types of paints, their characteristics and purpose. Composition of paints. Painting process. Application of paints. Defects in painting works. Wall cladding- stone cladding, tile cladding, and metal cladding. Stucco finish. Discussion: Applied finishes and building maintenance. MODULE 4
- 2. • Wall Finishes- is finish given to the wall to enhance the interior or exterior look of the structure. • Wall finishes used for the interiors are quite delicate and need maintenance. Applied finishes - Wall finishes.
- 5. WALL FINISHES – Plastering • Give joint less, hygienic ,easily decorated and usually smooth surface on background • Material of plastering consist of -binding materials -workability agents -aggregate -water -ancillary materials
- 6. Plastering Plastering is done to achieve the following objects To protect the external surfaces against penetration of rain water and other atmospheric agencies To give smooth surface in which dust and dirt cannot lodge To give decorative effect To protect surfaces against vermin. To conceal inferior materials or defective workmanship
- 7. Properties of good Plaster It should be hard and durable It should be possible to apply it during all weather conditions It should adhere to the background and should remain adhered during all climatic changes. It should be cheap and economical It should offer insulation against sound and high resistance against fire It should effectively check the penetration of moisture from the surfaces It should possess good workability
- 8. WALL FINISHES – Plastering • Type of background for plastering work -Clay brick -blockwork -concrete -boards
- 9. Plastering Tools GAUGING TROWEL A gauging trowel is used for gauging small quantities of materials and for applying mortar to mouldings, corners etc. The end of the trowel blade may be either pointed or bull-nosed. FLOAT A float is used for applying and spreading mortar on the surface . There are two types of float 1. Metal float. 2. Wooden float.
- 10. PLASTERING MATERIALS: • Cement • Lime or clay • Aggregates • Water • Accelerator • Admixture
- 11. There are several different types of Plaster available such as : (a) Lime Plaster (b) Cement Plaster (c) Mud Plaster (d) Stucco Plaster
- 12. LIME PLASTER • When lime is used as the binding materials, it is called lime plaster. • Lime plaster is type of plaster composed of hydrated lime, sand and water. • Lime plaster is similar to Lime mortar, the main difference is the based on use rather than composition. • Hydraulic lime is harder and stronger .Mortar for lime plaster is usually prepared by mixing sand and lime in equal proportions. • Cement is small quantity added to the mixture to improve its strength
- 13. LIME PLASTER –Properties • offer sustainable benefits • breathability and flexibility for the building. • contributes to a healthy internal environment • an economical, practical alternative to gypsum or patent cements that have little or no vapour permeable qualities. • high alkalinity prevents the build up of mold, which is particularly important in historic buildings restoration • manufacturing process produces less carbon dioxide than ordinary building materials. • reabsorb carbon dioxide in the air during the curing process, lowering its carbon footprint throughout the buildings life.
- 14. • Slaked fat lime is used to prepare mortar for plastering • Fat lime is used for finishing coat in plastering, white washing • Kankar lime is used for making masonry mortars, plastering and white washing. LIME PLASTER
- 15. CEMENT PLASTER • When cement is used as the binding materials, it is called cement plaster. • Cement plaster is usually applied in one coat. • The thickness of coat can be 12mm, 15mm or 20mm depending upon the site conditions and type of building. • It is prepared in the form of mortar with cement, sand and water in proper proportions and applied on masonry manually to achieve a smooth finish or sand faced finish.
- 16. CEMENT PLASTER – Properties • It is especially suited for damp condition. • Cement plaster can be used for plastering both the external walls and the internal walls and ceilings of the building. • For external surfaces ( 1:3 ),for internal surfaces ( 1:4 ). • The external cement plaster on the building facade is the first line of defense for the building from wind, rain, and harmful industrial gases and vehicular pollution. • Unlike gypsum plaster, cement plaster is resistant to moisture.
- 17. CEMENT PLASTER – Properties • The final finish of cement plaster is very rough and grey in colour. Hence, the walls have to be treated with POP punning (plaster of Paris punning) to achieve a smooth finish before the application of wall paint. • Punning is the application of thin layers of plaster or mortar on a wall to achieve a smooth and flat finish. • Cement plaster has the tendency to shrink, which results in hairline cracks on the plastered surface. • The cement-plastered surface needs curing (a chemical reaction that achieves strength) with water for at least seven days. Do note that improperly cured walls develop cracks. • Cement plaster is prone to attacks by mould or mildew.
- 18. GYPSUM PLASTER. • These are that type of plasters in which gypsum is used as a Binding Material instead of Cement or Lime. • The Gypsum Plaster are commonly used for making Architectural fancies and Decorative Designs on wall and roofs. • Their most important Properties are: a) They have great resistance to fire. b) They provide comparatively better insulation against heat and sound. c) They set and harden quickly. d) They undergo very little expansion and contraction.
- 19. GYPSUM PLASTER • They are made from natural gypsum rock which is a hydrated sulfate of Calcium. This rock is burnt at suitable temperature of ( 110 centigrade ) • At this temperature, most of the water of crystallization is driven off. • The resulting product is an Anhydrite, Commonly called Plaster of Paris. Calcination of Gypsum Plasters is done very carefully, because of over-burning and under-burning. • It is durable and finer as compared to Plaster of Paris
- 20. GYPSUM PLASTER - Properties • Gypsum plaster is factory-made. • Unlike cement plaster, it is white. • It is available in powdered form and is mixed with water to form a ready paste that can be directly applied to the wall and ceiling surfaces at site. • The approximate thickness of gypsum plaster is 11 millimeters for walls and 8 millimeters for the ceiling. • Gypsum plaster is also used to fabricate ceiling cornices and mouldings. • It gives the walls and ceilings a smooth, level surface that is ready to receive paint. Hence, it reduces POP punning costs which have to be incurred for cement plastered surfaces. • The gypsum plaster paste is very easy to work with and prepare, in comparison to cement plaster. • Gypsum plaster is highly resistant to mold and mildew. • Gypsum plaster does not shrink as it undergoes very little expansion and contraction.
- 21. GYPSUM PLASTER - Properties • The disadvantage of gypsum plaster is that it can only be used in the interiors of the building; it is not suitable for external plastering. • Gypsum plaster should not be used in moisture-laden areas like the bathrooms, kitchens, balconies or damp basements. • Gypsum is a superior finish compared to cement plaster. However, it is advisable to go with gypsum plaster for the internal walls and ceilings and use cement plaster for the exteriors of the building.
- 22. GYPSUM PLASTER BOARDS It is a gypsum product of recent origin made of thin layers of card board or wood cemented together with wall plaster, used for lining walls and ceiling of buildings. The boards may be strengthened by incorporating fibres as fibrous gypsum plaster boards. Sissal or coconut fibres are generally used.
- 23. ADVANTAGES OF PLASTERING a) Easy in application b) Plaster is the most common form of interior wall finishing c) If properly mixed and applied, a plaster coating creates a stronger and more durable. DISADVANTAGES OF PLASTERING a) When plaster cracks then difficult to repair. b) Repairing is very expensive. c) Despite the extra labor of hanging and finishing drywall, it tends to be less expensive than plastering
- 24. DEFECTS IN PLASTERING The following defects may arise in plaster work. • Blistering of plastered surface: This is the formation of small patches of plaster swelling out beyond the plastered surface, arising out of late slaking of lime particles in the plaster. • Cracking - consists of formation of cracks or fissures in the plaster work resulting from the following reasons. ◦ Imperfect preparation of background ◦ Structural defects in building ◦ Discontinuity of surface ◦ Movements in the background due to its thermal expansion or rapid drying ◦ Movements in the plaster surface itself, either due to expansion or shrinkage. ◦ Excessive shrinkage due to application of thick coat ◦ Faulty workmanship.
- 25. • Efflorescence It is the whitish crystalline substance which appears on the surface due to presence of salts in plaster making materials as well as building materials like bricks, sand, cement etc and even water. • This gives a very bad appearance. It affects the adhesion of paint with wall surface. Efflorescence can be removed to some extent by dry bushing and washing the surface repeatedly. • Flaking : It is the formation of very loose mass of plastered surface, due to poor bond between successive coats. • Peeling: It is the complete dislocation of some portion of plastered surface, resulting in the formation of a patch. This alsoresults from imperfect bond. DEFECTS IN PLASTERING
- 26. DEFECTS IN PLASTERING • Popping: It is the formation of conical hole in the plastered surface due to presence of some particles which expand on setting • Rust Stains: These are sometimes formed when plaster is applied on metal laths • Uneven surface: This is obtained purely due to poor workman ship.