TYPES OF DEFECTS IN PLASTER This post describes 7 different categories of defects most frequently noticed in plaster (as mentioned below) Non-structural cracks Structural cracks Debonding Lack of hardness Grinning Expansion Popping The causes and repair methods for each are discussed below. 1. Non-structural cracks Crazing is a network of fine cracks, usually in a … Read more
Quality Assurance for Cement Plastering Plastering is a process of applying one or more coats of mortar to a concrete surface, brickwork, stone masonry or lathing. It must be durable such that it resists the penetration of moisture and should be able to weather uniformly. It should also be pleasing in appearance. These properties depend … Read more
Cement plastering is commonly used as ideal coating for external and internal surface of wall. Cement plaster is usually applied in a single coat or double coat. Double coat plaster is applied where thickness of plaster is required to be more than 15 mm or when it is required to get a very fine finish. … Read more
What is Efflorescence on Plaster Surface? Efflorescence is one type of defect found on plaster surface. Efflorescence is the whitish crystalline substance which appears on the surface of walls due to presence of soluble salts, such as suphates of sodium, calcium and magnesium. Why Efflorescence Happens on Plaster Surface? Presence of salts in the lime, … Read more
Recommended Plaster Specifications A list of specifications for mixes suitable for various situations, which cover single-coat, two-coat and three-coat work is given in the table below. No. of Coat of Plaster Situation Mix proportion by volume (Cement:Lime:Sand) Single coat plaster Both internal and external 1:0:3 1:0:4 1:0:6 1:1:6 1:2:9 Two coat plaster Both internal and … Read more
Effect of Atmospheric Conditions on Plaster The prevailing weather at the time of plastering or during the setting, drying and hardening period may affect the finished work as follows: 1. Frost The destructive effect of frost on plaster work is significant. Unless special precautions are adopted, plastering work shall be suspended entirely during frosty weather. … Read more
Thickness of Plastering Finishing coats (and single-coat work, where employed) should be of such minimum thickness as just to provide a sufficient body of material to harden satisfactorily under the site conditions in any particular case. The total thickness of two-coat work exclusive of keys or dubbing out shall be generally about, but shall not … Read more
Number of Plaster Coats for Different Backgrounds The ideal number of coats, where practicable, is two, namely, the undercoat followed by a finishing coat. It is recognized, however, that much successful work has been carried out in the past with only a finishing coat plaster on reasonably plane backgrounds of brick, concrete and similar materials. … Read more
Importance or Objectives of Plastering Appearance To improve the appearance of the surface by providing an even, smooth, regular, clean and finished surface. Protection In case of external plastering, the objective is to preserve and protect the surface from atmospheric influences by acting as a protective coating. In case of internal plastering, the basic object … Read more
Blistering The development of one or more local swellings on the finished plaster surface. Cracking The development of one or more fissures not assignable to structural cause. Crazing The development of a series of hair cracks on the finished plaster surface. Known as ‘map crazing’, when it forms a haphazard pattern over the wall surface … Read more