Last Updated:9 December 2017 © LMS SEGi education

Last Updated:9 December 2017 © LMS SEGi education group 1 BUILDING CONSTRUCTION II ECM 3154 WEEK 9 INTERNAL CONSTRUCTION AND FINISHES – WALL FINISHES 1 PowerPoint® Slides by Zamzarina Bt Md.Judyar

Last Updated:9 December 2017 © LMS SEGi education group 2 CHAPTER OVERVIEW This chapter brings the student through the internal construction and finishes for partitions.

Last Updated:9 December 2017 © LMS SEGi education group 3 LEARNING OBJECTIVES To explain the types, functions, methods and performance standards of internal partitions as well the various types of wall finishes.

Last Updated:9 December 2017 © LMS SEGi education group 4 LEARNING OUTCOMES On completion of this topic, students should be aware of the code requirements for various types of partitions and select appropriate designs and materials for interior partitions.

Last Updated:9 December 2017 © LMS SEGi education group 5 INTRODUCTION The use of external rendering has been common for many years. The use of renders has changed over the years and in today's industry render is applied as a finishing material and weatherproofed. In the past, render was used as a cheap finish which could be used to represent more expensive finishes such as stonework.

Last Updated:9 December 2017 © LMS SEGi education group 6 INTRODUCTION Original renders were made from sand and lime but the introduction of Portland cement developed a render with good waterproofing qualities. The modern construction industry uses renders in order to cover blockwork and/or common brickwork in order to provide a decorative finish or a base coat for an applied finish for example pebble dash. This reputation is hardly deserved as most failures are caused by poor workmanship, poor detailing, incorrect specification and the use of renders on unsuitable backgrounds.

Last Updated:9 December 2017 © LMS SEGi education group 7 APPLICATIONS The modern construction industry uses renders for a wide range of applications: to prevent damp penetration to cover common brickwork and blockwork to provide a smooth background for paint application to provide a key for a pebble dash finish to improve the thermal insulation value of a wall from the exterior.

Last Updated:9 December 2017 © LMS SEGi education group 8 DEFINITIONS OF RENDERS Renders are surface coatings, usually based on a mixture of sand, cement and lime with the addition of either chemicals or aggregate. In certain cases renders contain additives such as resin or binders. Rendering involves the application of layers of mortar applied to the face of the wall. In most cases this will include the base coat and the finishing coat.

Last Updated:9 December 2017 © LMS SEGi education group 9 APPEARANCE The type of finish applied to render will vary with location, particularly in relation to adjacent footpaths and driveways. The general requirements for resistance to abrasion or impact affect both the strength of the mix specified and the type of the finish that is appropriate, since rough textured finishes are more liable to damage than smooth finishes.

Last Updated:9 December 2017 © LMS SEGi education group 10 APPEARANCE Other constraints to be considered when choosing the finish to render will include: the degree of exposure the appearance required the nature of the backing material the presence of any pollutants.

Last Updated:9 December 2017 © LMS SEGi education group 11 TYPES OF FINISHES i. Dry dash / pebble dash These give a rough finish of exposed pebbles or crushed stone graded from 6 to 13 mm and are produced by throwing the aggregate on to the surface of the freshly applied coat of mortar. In some cases the aggregate can be lightly pressed into the mortar to improve bonding.

Last Updated:9 December 2017 © LMS SEGi education group 12 TYPES OF FINISHES ii. Roughcast, wet dash or harling This is a rough finish is produced by throwing on a wet mix containing coarse aggregates and a cement binder. The aggregate in the finish coat is composed of sand and crushed stone or gravel from about 6 to 13 mm, the proportions of sand and gravel being adjusted according to the effect required. Roughcast finishes are applied on an undercoat with a spattered coat beneath it, like pebbledash finishes they are satisfactory for use in severe conditions.

Last Updated:9 December 2017 © LMS SEGi education group 13 TYPES OF FINISHES iii. Smooth floated finishes Smooth finishes to render are achieved by using a wood, felt or cork faced float to provide the surface finish. Coarse sand is recommended for this type of rendering especially in exposed conditions where rain and frost are likely to be severe.

Last Updated:9 December 2017 © LMS SEGi education group 14 TYPES OF FINISHES iv. Artificial masonry The position of the random joints is marked onto the render coat. A band of sand cement mix is laid onto the marks and then cut to a width of 12mm with a 12mm wide straight edge rule so that both edges are cut at the same time. These joints are left overnight to harden. The stones are then filled in with each one being tucked into the joints, to give them a boldness to their appearance. The thickness of each stone will vary and their surfaces 'rubbed up' with either a newspaper, wire brush or similar implement to give them their own individual appearance.

Artificial masonry Last Updated:9 December 2017 © LMS SEGi education group 15

Last Updated:9 December 2017 © LMS SEGi education group 16 TYPES OF FINISHES v.Textured finishes Textured finishes are produced by treating freshly applied finishing coats with various tools to produce a variety of patterns and textures. Typical finishes are English cottage, torn, stucco, stapled stucco, fan textures and scraped finish. The final coating of mortar is leveled and allowed to set for several hours before being marked or scraped with the appropriate tool. Textured and scribed finishes are suitable for all backing materials and conditions of exposure and are less prone to craze than smooth finishes.

Textured finishes Last Updated:9 December 2017 © LMS SEGi education group 17

Last Updated:9 December 2017 © LMS SEGi education group 18 TYPES OF FINISHES This is especially true of scribed or tooled finishes because the surface layer of very fine particles of sand and cement, which are likely to shrink and crack, is removed by the scraping action. In industrial areas more heavily textured finishes will tend to get dirty more quickly than the other types due to the increased amount of pollution. Highly textured finishes should be applied to a reasonably low suction coat otherwise the workability of the various coats tends to be lost before the required finish is achieved.

Last Updated:9 December 2017 © LMS SEGi education group 19 OTHER FINISHES These can be based on a variety of organic binders. They can range from artificial stone paints and sand textured paints to coloured textured compositions applied by spraying. This type of finish will normally will be applied by a specialist contractor. These finishes may be used as a decorative medium on cement based undercoats or applied directly to other suitable backgrounds such as concrete blockwork.

Last Updated:9 December 2017 © LMS SEGi education group 20 CHARACTERISTICS OF FINISHES i.High density Dense clay or concrete bricks and blocks or closed surface lightweight aggregate concrete. These units have low porosity and limited suction rates and will frequently have smooth surfaces providing little mechanical key. ii.Moderately strong and porous Clay, calcium silicate or concrete bricks and blocks may be in this category. The background normally offers some suction and mechanical key.

Last Updated:9 December 2017 © LMS SEGi education group 21 CHARACTERISTICS OF FINISHES iii. Moderately weak and porous This background would include lightweight aggregate concrete, aerated concrete blocks and relatively weak bricks. Care is needed in selecting rendering for these backgrounds as shrinkage of unduly strong rendering is liable to lead to shearing of the surface of the background material

Last Updated:9 December 2017 © LMS SEGi education group 22 CHARACTERISTICS OF FINISHES iv. Metal lathing Expanded metal lathing or welded mesh backgrounds are frequently used for remedial work, particularly when the background material is friable. Stainless steel is the ideal material but ferrous metal may be used if three coat work is to be applied. In this case a dense impervious first coat should be used to prevent rusting of the ferrous metal.

Last Updated:9 December 2017 © LMS SEGi education group 23 CHARACTERISTICS OF FINISHES v. High sulphate backgrounds Some bricks contain appreciable amounts of soluble salt including sulphates which can also be found in old walls during renovation work. The salts can attack elements of Portland cement and will require the use of spec

Last Updated:9 December 2017 © LMS SEGi education group 24 RENDER DETAILING constructionphotography.com

Last Updated:9 December 2017 © LMS SEGi education group 25 RENDER DETAILING

Last Updated:9 December 2017 © LMS SEGi education group 26 QUIZZES 1. Define rendering. ……………………………………………………………………………………………………………………………… 2. Determine any four characteristics of wall finishes. ………………………………………………………………………………………………………………………………………………

Last Updated:9 December 2017 © LMS SEGi education group 27 KEY TERMS 1.Low porosity Definition Porosity or void fraction is a measure of the void (i.e., "empty") spaces in a material, and is a fraction of the volume of voids over the total volume, between 0–1, or as a percentage between 0–100%. 2. Ferrous metal Definition A metal that contains iron. The most common ferrous metal is steel. 3.Friable Definition Easily broken into small fragments or reduced to powder Last Updated:9 December 2017 © LMS SEGi education group 27

Last Updated:9 December 2017 © LMS SEGi education group 28 REFERENCES Chudley, R., & Greeno, R., 2005. Construction Technology, 4th ed. England: Pearson. Chudley, R., & Greeno, R., 2001. Advanced ConstructionTechnology, 3rd ed. England:Longman. Spence, W.,D., 2006. Construction Materials, Methods, and Techniques, 2nd ed. US:Delmar. constructionphotography.com retrieved 19th August 2011