PLASTERING

这following topics are covered in this post.

1. What is plastering?
2. 优质石膏的要求是什么？
3. 不同类型的灰泥用于抹灰
4. Number of coats of plastering
5. 如何在抹灰之前准备背景？
6. 对于不同情况，推荐的迫击炮混合物是什么？
7. 抹灰的缺陷是什么？

What is plastering?

抹灰是覆盖墙壁，圆柱，天花板和其他带有薄砂浆层的墙壁，柱子，天花板和其他建筑物组件的过程，形成光滑的耐用表面。18新利官网登录在线砂浆的涂层称为石膏。

进行抹灰以实现以下对象：

• 为了保护外面，免受雨水和其他大气机构的渗透。
• 为了给出光滑的表面，灰尘和污垢无法放置。
• 发挥装饰效果。
• To protect surfaces against vermin.
• 掩盖劣质材料或做工缺陷。新利客户

优质石膏的要求

这plaster material should fulfill the following requirements:

• 它应该遵守背景，并应在季节和其他大气条件的所有变化中保持粘附。
• 它应该坚硬耐用。
• It should possess good workability.
• It should be possible to apply it during all weather conditions.
• It should be cost efficient.
• 它应该有效检查水分的渗透。

Types of mortars for plastering

这selection of type of plaster depends upon the following factors:

• 结合材料的可用性。新利客户
• Durability requirements.
• Finishing requirements.
• 一种tmospheric conditions and variations in weather.
• 表面的位置（即暴露的表面或内部表面）。

Cement mortar

水泥砂浆是最好的砂浆外部塑料tering work since it is practically non-absorbent.

It is also preferred to lime plaster in both rooms etc., and in damp climates. Cement mortar is much stronger than lime mortar. The mix proportion (i.e. cement：sand) may vary from1：4至1：6。Sand used for plastering should be clean, coarse and angular.

Cement plaster is applied either in two coats or in three coats, the former being more common.

对于下部工作，有时会提供单层石膏。

Number of coats of plaster

要完成抹灰的背景取决于墙壁结构的类型，例如随机瓦砾（R.R.）砌体，块状瓦砾砖石，砖砌砖石

背景	没有外套
石头工作	3or 2
Brick work or hollow blocks	2or 1
原地混凝土	2or 1

笔记：如果在single coat only，厚度should not exceed 12 mmnor should it be less than 6 mm。

Two coat plaster

采用以下程序：

• 这background is prepared by raking the joint to a depth of 20 mm, cleaning the surface and well-watering it.
• 如果要贴贴的表面非常不平衡，则在第一层涂层之前涂上初步涂层以填充空心。
• 这first coat or rendering coat of plaster is applied, the thickness being equal to the specified thickness of plaster less 2 to 3 mm. In order to maintain uniform thickness of plaster, 15 cm x 15 cm size. Two dots are so formed in vertical line, at a distance of about 2 m, and are plumbed by means of a plumb. A number of such vertical screeds are formed at suitable spacing. Cement mortar is then applied on the surface between the successive screeds and the surface is properly finished.
• 使变硬之前,它是适当的努力provide mechanical key for the final or finishing coat. The rendering coat is trowelled hard forcing mortar into joints and over the surface. The rendering coat is kept wet for at least 2 days, and then allowed to dry completely.
• 最终或精加工的厚度可能在2至3毫米之间变化。在涂上最终涂层之前，渲染涂层均匀地减湿。将最终涂层用木质浮子涂在真实的表面上，并用钢箭完成。越远越好，从顶部到底部开始使用整理外套并在一个操作中完成以消除连接标记。

三层石膏

这procedure for applying three-coat plaster is similar to the two-coat plaster except that an intermediate coat, known as漂浮的外套被申请;被应用。这件石膏涂层的目的是将石膏带到均匀的表面。保留渲染外套，浮涂层和精加工的厚度9 to 10毫米，6 to 9mm and2to 3MM分别。渲染外套变得粗糙。

这漂浮的外套is applied about 4 to 7 days afterapplying the first coat. The finishing coat may be applied about 6 hours after the application of floating coat.

Single coat plaster

This is used only in inferior quality work. It is applied similarly as two-coat plaster except that the rendering coat, as applied for two-coat plaster, is finished off immediately after it has sufficiently hardened.

Preparation of background

For plastering new surfaces, all masonry joints should be raked to a depth of 10 mm in brick masonry and 15 mm in stone masonry for providing key to the plaster. All mortar droppings and dust, and laitance (in case of freshly laid concrete) should be removed with the help of stiff wire brush. Any unevenness is levelled before rendering is applied. For finish applied in three coats, local projections should not be more than 10 mm proud of general surface and local depressions should not exceed 20 mm. For two-coat plaster, these limitations are 5 mm and 10 mm respectively. The surface should be washed with clean water and kept damp uniformly to produce optimum suction. In no case should the surface be kept so soaked that it causes the green mortar to slide off, or so dry that it causes strong suction which withdraws moisture from mortar and makes it weak, porous and friable. If plaster is to be applied on old surface, all dirt, oil, paint etc. should be cleaned off. Loose and crumbling plaster layer should be removed to its full thickness and the surface of the background should be exposed and joints properly raked. The surface should be washed and kept damp to obtain optimum suction.

推荐的迫击炮混合在不同情况下

SL	情况	Composition of Mortar	I.S. Grading of Lime
1	External Plaster in localities where rainfall is less than 500 Mm per year and where sub- Soil water is not within 2.5 m Below the ground surface:
	(a) Below D.P.C	1cement 6 sand	-
		1水泥2石灰9沙	B or C
		1石灰2砂	一种
		1lime 1 sand 1 surkhi	B or C
		1石灰2 surkhi	B or C
	(b) Above D.P.C	1水泥2石灰9沙	B or C
		1石灰2砂	一种
		1lime 1 surkhi sand	B or C
		1石灰2 surkhi	B or C
2	降雨量降雨量超过1300毫米的地方的外部石膏，地下水的地面水不到地面2.5m以内：
	(a) Below D.P.C	1cement 4 sand	-
		1cement 1 lime 6 sand	B or C
		1石灰2 surkhi	B or C
	(b) Above D.P.C	1水泥2石灰9沙	B or C
		1石灰2砂	一种
		1lime 1 sand 1 surkhi	B or C
		1石灰2 surkhi	B or C
3	External plaster in localities where the subsoil water is within 2.5 m of the ground
	在D.P.C下方	1水泥3沙
4	所有地方的内部石膏	1石灰2砂	一种
		1lime 1 surkhi 1 sand	B or C
		1石灰2 surkhi	B or C
		1水泥2石灰9沙	B or C

笔记：the ratio of lime varies with % purity of lime and these ratios may be suitably adjusted depending upon local practice.

Defects in plastering

石膏工作中可能会出现以下缺陷：

1. 抹灰表面的起泡

这是由灰泥表面以外的小灰泥肿胀的小斑块的形成，是由于灰泥中的线颗粒的后期捕捞而产生的。

2. Cracking

Cracking consists of formation of cracks or fissures in the plaster work resulting from the following reasons:

• 背景的不完美准备。
• Structural defects in building.
• 表面不连续。
• Movements in the background due to its thermal expansion or rapid drying.
• 石膏表面本身的运动，要么是由于膨胀（如果石膏石膏）或收缩（如果是石灰砂灰泥）。
• Excessive shrinkage due to application of thick coat.
• 做工错误

3. Crazing

It is the formation of a series of hair cracks on plastered surface, due to same reasons which cause cracking.

4. Efflorescence

由于灰泥制造材料中存在盐以及砖，沙子，水泥等，它是由于存在盐而出现在表面上的白色晶体。新利客户这使外观非常糟糕。它会影响油漆与壁表面的粘附。

Efflorescence can be removed to some extent by dry brushing and washing the surface repeatedly.

5. 剥落

It is the formation of very loose mass of plastered surface, due to poor bond between successive coats.

6. 脱皮

它是一部分灰泥表面的完全脱位，导致斑块的形成。这也是由于不完美的键。

7. 弹出

It is the formation of conical hole in the plastered surface due to presence of some particles, which expand on setting.

8. 铁锈污渍

当将石膏涂在金属板条上时，这些有时会形成。

9. Uneven surface

This is obtained purely due to poor workmanship.