This code of practice outlines the recommended procedures for preparing and applying whitewash and colour-wash coatings on concrete, masonry, and plaster surfaces within buildings. It covers essential aspects such as surface cleaning, material standards, and application methods to achieve hygienic, visually appealing, and consistent finishes. The standard is indispensable for professionals engaged in building finishing and upkeep.
Overview
This code of practice outlines the recommended procedures for preparing and applying whitewash and colour-wash coatings on concrete, masonry, and plaster surfaces within buildings. It covers essential aspects such as surface cleaning, material standards, and application methods to achieve hygienic, visually appealing, and consistent finishes. The standard is indispensable for professionals engaged in building finishing and upkeep.
Audience
Contents
Structure
This section defines the purpose and extent of the code, detailing procedures for preparing concrete, masonry, and plaster surfaces before applying whitewash and colour-wash. It emphasizes cleaning old coated surfaces by removing dust, loose lime deposits, and foreign substances, with scraping required for heavily scaled areas. The section also explains rounding off test results following IS 2-1960 and highlights harmonization with international standards and local site conditions.
Focuses on the materials necessary for whitewashing and colour-washing, including the use of building lime, common salt, pigments such as ultramarine blue and iron oxide, and copper sulphate. It outlines surface cleaning requirements prior to application and describes the typical composition of whitewash and colour-wash mixtures. The section also provides references to relevant Indian Standards for specific materials.
Details safety guidelines for erecting scaffolding and using ladders during whitewashing and colour-washing operations. It advises avoiding placing scaffolds on coated surfaces, securing suspended platforms adequately, and using protective padding to prevent damage. The section highlights the need for ceiling scaffolding when working overhead and recommends compliance with IS 3696 for scaffold safety.
Describes cleaning procedures for different surface types including new surfaces, old surfaces with existing coatings, and those affected by smoke or soot. Methods include thorough brushing, scraping with steel tools, and washing with water. Emphasis is placed on ensuring dry and sound surfaces free from loose particles to promote proper adhesion of coatings.
Explains how to prepare whitewash by slaking unslaked lime with water, adding additives like gum and sodium chloride to enhance adhesion and curing, and optionally incorporating pigments such as ultramarine blue for tinting. For colour-wash, it recommends mixing lime with mineral pigments stable in alkaline environments. The section also describes the addition of tallow or oils to improve water resistance for exterior applications.
Outlines the step-by-step application process, starting with surface cleaning, applying an initial coat of whitewash on new surfaces, followed by at least two coats of colour-wash. It stresses preparing sufficient quantities in a single batch to maintain consistent colour and conducting small test patches to verify shade uniformity before full application.
Emphasizes applying two coats of whitewash before colour-washing to ensure proper adhesion and a uniform finish. It reiterates the necessity of clean, dry, and sound surfaces and adherence to international best practices. The section provides a summary of coat application and reinforces the importance of following IS 2-1960 for rounding numerical data.
Frequently Asked
The standard specifies using freshly burnt Class 'C' lime, also known as Fat lime, compliant with IS 712-1964. This lime should be slaked on-site by mixing approximately 5 liters of water per kilogram of unslaked lime and allowed to stand for 24 hours before straining. For exterior applications, additives like tallow or linseed/castor oil are incorporated with quicklime to enhance water resistance. Additional additives such as sodium chloride and ultramarine blue pigment may be included to improve hardness and appearance.
Old surfaces requiring a new colour shade must first have the existing colour-wash completely removed by brushing, scraping, or other appropriate cleaning methods. The surface should then be broomed to eliminate dust and loose debris. Any patch repairs should be treated with a coat of colour-wash prior to coating the entire surface. If the new colour matches the existing one, the primary whitewash coat can be omitted. These steps ensure good bonding and a uniform, durable finish.
Mould or moss growth should be physically removed by scraping with a steel scraper. Following this, an ammoniacal copper solution is applied, prepared by dissolving 15 grams of copper carbonate and 60 milliliters of liquor ammonia in 500 milliliters of water. This treatment must be allowed to dry thoroughly before coating. Alternatively, a 2% sodium pentachlorophenate solution can be used. The surface should then be cleaned by brushing and washing to ensure a clean, mould-free base for application.
For new surfaces, the standard recommends applying one initial coat of whitewash followed by a minimum of two coats of colour-wash, totaling at least three coats. For existing surfaces, if the new colour matches the old, only the colour-wash coats are applied after necessary patch repairs without a whitewash base. If the colour differs, two coats of whitewash should precede the colour-wash coats. This layering ensures a durable, uniform finish.
Consistent colour and finish are achieved by thoroughly preparing the surface according to whether it's new or old, applying the correct sequence of coats (whitewash followed by colour-wash for new or colour-wash over repairs for old surfaces), and mixing sufficient quantities of colour-wash in a single batch to prevent shade variations. Testing a small area (approximately 0.1 m²) prior to full application helps verify uniformity. Using mineral pigments stable in lime and adhering to the prescribed number of coats ensures an even, aesthetically pleasing finish.
Ask AI about any clause, requirement, or provision in IS 6278. Get instant, clause-cited responses powered by our indexed library.
Free tier includes 150 queries (50 AI + 100 Reference) · No credit card required