Presentation on theme: "INAR 342: FINISHING WALL FINISHES. Walls are the vertical building elements which divide the spaces from each other. Walls generally have load bearing,"— Presentation transcript:
Walls are the vertical building elements which divide the spaces from each other. Walls generally have load bearing, separation, insulation and conservation functions. Layers of a Wall
INTERNAL PLASTERS Plastering is a centuries-old craft which provides a comparatively uneven wall with a smooth, flat surface. In the past, plaster was based on lime, but today it is also based on “gypsum” and “cement”. Plaster is applied to wall or other surfaces as a wet mixture of binding material (lime, cement or gypsum), aggregate (usually sand) and water.
Types of Internal Plasters 1. Mineral Plasters (Binding materials are lime, cement and gypsum which are inorganic materials. Also aggregates and colour pigments are obtained from natural minerals) 1.1 Lime and Cement Plasters 1.2 Gypsum Plasters 2. Polymer Plasters ( Binding material is a polymer resin like acrylic)
LIME AND CEMENT PLASTERS Materials and mixes used in plastering are either: A matrix or A matrix plus aggregates MATRIX: a mix, which has a setting action. THE AGGREGATE: the inert filler.
Purposes of aggregates: To provide special wearing qualities To provide better workability To provide regulation of shrinkage To provide cheapening of the mix cost To improve insulation
Lime Plaster The binding material is only lime and also include sand and water. (Kireç Sıva) Before the 19 th century Portland cement was not manufactured and the matrix then used was lime. The mix then was: 1 part of lime + 3 part of sand + water
Cement Plaster This kind of plasters include cement as a basic binding material, however it is include also small amount (25 %) of lime in order to prevent cracks and increase workability by increasing the setting time.
Lime and Cement Plaster (Stucco) This kind of plasters are include cement in order to increase the strength of the plaster. The ratio of the cement is 20 or 30 % of the lime ratio. Stucco makes an excellent exterior and interior wall covering, as it is attested by its long and much appreciated history.
During the old periods of time, before the Modern Era, lime has been used in stucco as the only matrix available for builders. But its slow hardening has led to the use of Portland cement in the mixture of stucco, after the Portland cement was discovered at the beginning of the 19 th century. Portland cement is today the most widely used material for such purpose. With white Portland cement and lime, a wide range of colors is obtainable, particularly when colored sands and stone chips are employed with the colored pigments. If the surface to be stuccoed is masonry, two coats are applied; if the surface is metal lath, three coats are required.
LIMES The row materials from which building limes are obtained are limestones and chalks. Both of these materials are largely composed of calcium carbonate and were formed over a period of millions of years by calcium deposits mostly from marine life in the oceans of the world. As a result of later earth movements, layers of limestone are to be found in many countries of the world.
The limestone and chalk is quarried, crashed and then heated in kilns to drive out the carbon dioxide content. The resulting material withdrawn from the kilns is calcium oxide, known also as burnt lime, lump lime, quick lime or as lime. The materials are slaked with water to form slaked lime (calcium hydroxide), also known as lime putty. Lime putty sets by a process of carbonation as a result of loss of water and also by combining chemically with carbon dioxide from the atmosphere
Classification of limes: The classification of limes is based on the degree of hydraulicity as follows: 1. Non-hydraulic limes: This is the purist type of lime containing up to 98% calcium oxide. This produces a putty lime, which has high plasticity and workability and sets slowly by carbonation.
2.Semi-hydraulic limes These limes contain sufficient impurities giving the limes hydraulic tendencies (hardening or setting under water)
3.Eminently hydraulic limes These contain high degree of impurities, which give the resulting slaked lime properties similar to Portland cement. A well-known type of hydraulic lime is called Blue Lias lime.
4.Hydrated Limes This lime is obtained by slaking high calcium lime under controlled conditions in a manufacturer’s plant, after which the excess water is dried off. The resulting powdered hydrated lime is sold in 25 kg bags. Hydrated lime, soaked in water, will produce a lime putty with improved yield and workability.
TOOLS FOR PLASTERING PLUMB BOB These are used to plumb vertical dots. They are often made of lead, at least 350 gr in weight, with a hole bored through the center. A string line is passed through the hole and knotted below. Gauge’s are pieces of timber with shoulders. They may be used in pairs, which must be identical in size so that the plumb line, when suspended from the shoulder of the upper gauge, is an equal distance from the upper and lover dots.