BASE COAT PLASTER – INTERIOR & EXTERIOR
Basic Mortar plastering with Adhesives.
Plastering mortars are designed for leveling, smoothing or fine-smoothing uneven surfaces of walls. They are based on Fine aggregate, cement and adhesives, depending on applications and local expectations.
Finishes Of Plastering
1. Smooth Cast Plaster Finish
To obtain smooth cast finish, mortar used should be in the ratio 1: 3 [cement: sand]. Fine Sand should be taken to prepare the mortar. For spreading the mortar, skimming float or wood float is best suitable tool. Hence, smooth and levelled surface is obtained finally.
2. Rough Cast Plaster Finish
Rough cast finish is also called as spatter dash finish. Mortar used to get rough cast finish consist coarse aggregate along with cement and sand. Their ratio is about 1: 1.5: 3. The size of coarse aggregate used is 3mm to 12mm. Large quantity of mortar is taken by trowel and it is dashed into the surface and levelled using wooden float. Usually this type of plaster finish is preferred for external renderings.
3. Sand Faced Plaster Finish
To get sand faced finish two coats of plastering is required. For first coat, 12mm thick layer of cement sand mortar in 1: 4 ratio is preferred. The first coat should be provided in zigzag lines. And then it is allowed for curing for 7days.After that 8mm thick layer of second coat with cement and sand in 1:1 ratio is applied. Level the surface using sponge. Finally take some sand and screened it to obtain uniform grain size. The screened sand is applied on the second coat using skimming float or wooden float. Finally, sand faced finish with uniform grain size of sand is obtained.
4. Pebble Dash Plaster Finish
Pebble dash finish requires mortar layer of 12mm thickness with cement and sand in the ratio of 1: 3. After plastering pebbles of size 10mm to 20mm are dashed on to the plastered surface. Then press them into the plastered surface using wooden float slowly. After hardening they provide aesthetic appearance to the structure.
5. Scrapped Plaster Finish
To obtain scrapped finish, apply final coat of 6 to 12 mm thickness and allowed it to dry. After some time using steel blade or plate scrap the plastered layer up to 3mm depth. Scrapped finish is less liable to cracks.
6. Depeter Plaster Finish
This is also similar to pebble dash finish. But in this case pieces of gravel or flints are used in place of pebbles.
7. Textured Plaster Finish
Textured finish is obtained from the stucco plastering in which different textures or shapes are made on the final coat using suitable tools.