WALLS AND WINDOW TREATMENTS 3(1+2)

Lesson 3 : Materials For Internal Walls

Concrete

Concrete is a mixture of sand, coarse aggregate, Portland cement, and water. The sand used in concrete should be blank-run sand, which is fairly round in shape and of various sizes. The coarse aggregate is gravel or crushed stone. Concrete should have aggregate pieces no larger than one-quarter the thickness of the pour. For example, if the pour is less than 4 inches thick, the aggregate should be less than 1 inch in size. Portland cement is made of clay, lime, and other ingredients that have been heated in a kiln and ground into a fine powder.

1. The forms used on these walls maybe patterned or smooth, with the texture reflected on the interior surface. Currently many architects of contemporary buildings like commercial, industrial and educational fields are leaving poured concrete walls exposed on the interior.
2. The surface may also be treated by different surface appearance like bush hammering, acid etching and sand blasting.
3. Bush hammering is done with a power tool that provides an exposed aggregate face by removing the sand cement matrix and exposing the aggregate. Bush hammering produces the heaviest texture.
4. Sand blasting provides a textured surface, depending upon the amount and coarseness of the sand.
5. Acid etching just removes the surface. It left in it natural poured concrete state, the main problem faced will be using materials and accessories that will be compatible with cast concrete. Therefore, to overcome this problem it can be plastered.