Plastering: Plastering is the process for using mortar
coats on the exterior of walls, columns, ceiling to provide a sleek finish.
Mortar that is utilized in plastering may range from lime mortar, cement mortar
or lime-cement mortar. Lime mortar that is utilized should contain fat lime to
sand ratio of 1 : 3 or 1 : 4. If hydraulic lime is applied, it’s mix ratio
(lime: sand) is 1 : 2. Cement mortar of 1 : 4 or 1 : 6 mix is mostly utilized
for plastering, richer mix is applied for outside walls. Lime-cement mortar is
the combination of lime mortar and cement mortar in the ratio of (cement : lime
: sand) 1 : 1 : 6 or 1 : 1 : 8 or 1 : 2 : 8. Lime-cement mortar can save
significant plastering cost.
Lime mortar is generally applied in 3 coats whereas
cement mortar is used in two or three coats toward the stone and brick masonry.
Cement mortar is used in two or three coats toward concrete surfaces.
Most often, one coat of cement mortar is used for
concrete building blocks.
The first coat is useful for attaining level surface. The
final coat produces smooth surface. When three coats are applied, second coat
is called floating coat. The average density of first coat is 10 to 15 mm. The
density of middle coat is 6–8 mm. The density of final coat is just 2 to 3 mm.
When single coat is applied, the density remains among 6 to 12 mm. Such coats
are useful for concrete surfaces not uncovered to rain.
Pointing: In some cases, special mortar finishing work is
applied to the uncovered joints in place of providing plaster to the whole
surface of the masonry. It is known as pointing. It comprises of slanting the
joints to a depth of 10 mm to 20 mm and stuffing it with richer mortar mixes.
Toward lime mortar, the ratio of pointing mix is 1 : 2 and for cement mortar
pointing mix is applied in the ratio of 1 : 3. Pointing is mostly suitable for
stone masonry as stones contain eye-catching colors and strong resistance power
against water penetration. Pointing makes weaker part of masonry (i.e. to
joints) more accurate and it enhances the aesthetic view of the masonry.
Given below, some points of variations among plastering and
pointing.
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Published By
Rajib Dey
www.constructioncost.co
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