Hanson Precast Concrete
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Product Info - Applied Finishes Applied finishes fall into two categories: 1. Those applied after manufacture, 2. those applied during manufacture.
Off-Form Finishes
Finishes applied after manufacture are predominately paint systems,
Applied Finishes
to which precast concrete lends itself most successfully. Paint finishes
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have become popular in recent years and can produce a colourful, economical unit with consistent appearance. Previously they were used more for functional or architectural reasons, such as to produce an even colour when insitu and precast concrete were combined in the same facade. This can still be a valid reason for using such a finish. The process for painted finishes usually involves three steps, 1 primer, 2 texture and 3 finish coats. The texture stage may produce a range of surfaces from smooth to stippled to stucco, while the finish coats provide the colour and weathering properties. Finishes applied during manufacture include brick biscuits, tiles and dimension stone. It is important to carefully select the applied material to ensure it will bond successfully with the concrete backing, particularly where tiles are involved. In the case of dimension stone, however, bonding is to be avoided because of thermal expansion differences in the two materials, in which case they are connected mechanically.
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Hanson Precast Concrete
http://www.hansonpc.biz/products/appliedapp.shtml
Australian Precast Concrete home
about us
Walling Loadbearing Facades Cladding
products
services & solutions
news
case studies
Product Application - Applied Finishes The traditional use of applied finishes, after manufacture, has been to unite combined precast and insitu elements. A typical example of this
Hollowcore Wall Panels
is a Bondi Junction project where an even colour flows through the
Energy-efficient Facades
insitu work and the precast facade.
Off-Form Finishes Applied Finishes
A more recent example can be seen in the Quay Apartments where the lower levels are for car parking. The front facade is precast
Product Application
(incorporating planter boxes) with an applied finish which effectively
Design Data
unifies the precast and insitu sections of the building.
Exposed-aggregate Finishes
Another interesting application of applied finishes is to unify
Multiple Finishes
extensions to old buildings. While precast concrete can easily handle
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the job of recreating an existing facade, matching the usually weathered finish is not so easy. A painted finish to both the old
Applied finish on Bondi Junction project resulting in an even colour to both insitu and precast work
building and the new precast work can be an expedient solution as shown in the extensions to Botany Town Hall. The use of paint finishes to produce economical units, with consistent appearance, can be seen in many shopping centre and industrial applications. Finishes applied during manufacture include brick biscuits, tiles and dimension stone. While brick and tiles are not common in Australia, a good example of such an application is the Orange Civic Centre and Library. The 2400 mm wide precast panels had tiles inset into their face and ranged in height from 2600 to 7400 mm. The use of dimension stone has enjoyed greater application in Australia. An excellent example of this is seen in the 44-storey curved stairflights in the Grosvenor Place project.
The Quay Apartments where the precast facade to the carpark levels had an applied finish which united it with the insitu sections of the building
Botany Town Hall extension. The precast extension on the right is indistinguishable from the original structure through the use of a painted finish to both
Use of applied paint finish, in a shopping centre, to produce
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Hanson Precast Concrete
http://www.hansonpc.biz/products/applieddesign.shtml
Australian Precast Concrete home
about us
Walling Loadbearing Facades Cladding Hollowcore Wall Panels Energy-efficient Facades Off-Form Finishes Applied Finishes Product Application Design Data Exposed-aggregate Finishes Multiple Finishes Flooring
products
services & solutions
news
case studies
contact us
Design Data - Applied Finishes
FINISHES APPLIED AFTER MANUFACTURE ? PAINT FINISHES A typical texture system for precast concrete wall panels will involve three steps: 1. Primer 2. Texture 3. Finish Coat 1 - Primer Primer is the most important part of any system. It provides a sound base for adhesion of top coats. Water and solvent based primers are used. Water-based primers are most widely used for their
Structural Precast
convenience - low odour, water thinning and wash up.
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Solvent-based primers are used on "difficult" surfaces eg impervious, smooth surfaces or those with residual release agents. Water-based primers (and other water-based paints) contain emulsion as binder. Emulsions are discrete particles of resin dispersed in water. For this reason they do not penetrate smooth, impervious surfaces. In addition release agents can act as water repellents making water-based primers unsuitable for such surfaces. Solvent-based primers have the resin in solution. Solvent can dissolve release agents allowing the primer to penetrate and gain adhesion. In summary, solvent-based primers are preferred for precast as they are able to easily penetrate smooth dense surfaces to provide a sound base for adhesion of topcoats. In addition, they are fast drying with a two hour recoat and have excellent alkali resistance. 2 - Texture There is a wide range of products with a variety of builds and profiles. Roller Applied. - Roller application is quick and easy and does not require highly skilled applicators. "Stipple" finishes are the simplest systems requiring only primer and one or two coats of texture. Trowel Applied. - Application is slower and requires skilled applicators. After trow elling, the coating surface is worked with a polystyrene float to achieve the traditional scratch effect. Trowel coatings are available in 1, 1.5, 2 and 3 mm grades. Other trowelapplied products do not have coarse aggregate and leave a smooth render look. Spray Applied. - Textures can be applied with a hopper gun or spatter gun to achieve a "stucco" effect. Spray application is fast so application costs are reduced but some skill is required. 3 - Finish Coat Finish coats provide colour, dirt shedding and long-term decorative
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