In this article we are going to instruct you the joinery in a building plasterwork, so you can carry out your house joinery work in the best form but with the lowest expense.
In the first step in order to a joinery in the building plasterwork, cover the entire wall surface with plaster-soil. This manner decrease the expense, because you have a mortar with lower price, as well as the obtained plasterwork mortar has longer stiffening time, and also in compare to the white plaster is more shapeable.
But before starting, we have to know how the plaster-soil mortar is prepared:
First we have to sieve clay soil, and then add it to plaster. Quick stiffening is in fact plaster power that the ratio of the acquired mixture depends more upon the rapid stiffening. If the plaster you are using is fast-stiffening, then you have to utilize further clay soil and it is ideally 50 to 50.
In the second step, you have to put the obtained mixture inside a container that in masonry is called Estamboli, and then add some water. Water is spray over the mixture so that all plaster comes into contact with water. Later this mixture agitated as far as one homogenous and doughy material is resulted.
You should notice that prior to carrying out the plaster-soil, the whole essential works such as screed holding, chroming, unevenness on a wall, and ceiling balancing or its defects like rippling must be done.
For doing this, first of all choose a point on the wall, and with the help of plaster and trowel make a flat spot on the mentioned point. Then continue this point downward with the help of plumb-line, and then make small surface with soil and plaster on the wall that is aligned with the higher point. Again, with this method, make another point in the other wall corner. Then draw a string between the two points and make some same points with the use of plaster and trowel beneath the string at the distance of every one meter. Create all these spots in the way that all align with the string.
Then you must draw some lines, few centimeters in width, at the distance of every one meter. Don’t forget select a straight screed before doing this, then cause it to lean to two points on the top and bottom, and with plaster and soil fill its backside. This action which by plaster rail lines are made on a wall is called screed holding. Now you can fill the spaces between these plaster rail lines with plaster and soil, which are for joinery in the building plasterwork, and pull the screed over its surface. According to the smoothness of the plaster rail, the surface of the plasterwork will flatten as well.
It is necessary to be mentioned that factories manufacture special underlay plasters and plaster-soil that without any need to mix with soil can be used for joinery in building plasterwork.
It is very important to start from upper part, otherwise it overturns downward and destroys the down part. Generally in the building plasterwork, in order to the execution of plaster-soil and white plaster in joinery, first the upper parts are done, and upper part means the half upper part of a wall.
After executing the upper part, the rest half down part is done.
After drying out, both the upper and down half, we start to carry out white surfacing. Keep in your mind that always prepare some mortar in the container (Estanboli), since plaster mortar is fast stiffening. For making plaster mortar first pour some water into the container, then spread plaster powder and agitate it as far as one homogenous grout obtains.
After few minutes while plaster stiffened, we put it on the wall by trowel. For this, first put about a palmful plaster on the trowel and then pull the trowel in the direction from down to up. Pay attention that the angle between wall and trowel plate to be 45˚ and while the trowel is being pulled upward its angle is gradually being lowered and finally reached 10˚. If the trowel is pulled tangent on the wall, the plaster mortar will stick to it and rise on the wall.
For joinery in the building plasterwork, we put a palmful plaster on the trowel and pull it from down to up. At the first the angle between the trowel and wall ought to be 45˚, and while we pull it slowly from down to up, this angle must be lowered and finally reached 10˚. This technic is called open and closed trowel. Because at the first the angle between trowel and wall is larger and later slowly decrease. If the trowel is pulled tangent on the wall, the plaster mortar will stick to it and rise on the wall.
And conversely, if the angle between the trowel and the wall is larger, a deep scratch will remain on the wall and the trowel will dig out the plaster, hence the trowel and wall angle is very important in the constructional plasterwork for joinery.
While the desired surface was covered with plaster, we erase the trowel traces by screed or trowel worker. Under normal condition a dried white plaster has the thickness of 0.5 cm on a wall.
As to the joinery, we should notice that plaster is fast stiffening, so we cannot smoothen its surface. So prior to drying out the plaster we use very thin layer of dead plaster on it, and smoothen it by a trowel until we have very fine and smooth surface.
Perhaps you ask this question, what is a dead plaster? And how is it made? It is the plaster that does not toughen any more. For making this dead plaster, first you should sieve the plaster powder with a very small holes mesh, then spread it in the water like you did for mortar. You ought to agitate the mixture of plaster and water with your hands for about 10 to 15 minutes to prevent its stiffening and wait until completely homogenous mixture to obtain. This plaster dries out because of water evaporation from its surface and never toughens, and this is exactly why it gives more opportunity to workers to smoothen larger surfaces. This action has some defects as well, since it might scurf on the work surface. To prevent that, it is possible to use ivory plaster, but you should prepare lower amount of this plaster to hinder its waste.
How to conduct plaster spreading
Plaster sprayer machines are designed in the way that mix water and plaster in a particular proportion, and then lead the produced plaster dough to spout nozzles. Another pipe has been improvised over the nozzle tip, which is connected to the compressed air pump. The machine spreads this mixture into the air. The next step is plaster leveling with manual screed, and we simultaneously do the leveling work as well. It is economic to use plaster spraying with machine in large spaces. The advantage of this method is that we don’t have the plaster and soil stage anymore. This type of plaster can be sprayed on concrete without any intermediate in the thickness of 10 cm. In this method the plaster waste is minimum, since the plaster package is directly poured into the machine. Also this type of plasterwork is anti-moisture and anti-crack.
Approximately one hundred minutes is needed for this type of plaster spraying to achieve the initial stiffness.
Important issue number 1: if you use Hebelex walls for a building, if the executive team work on a clean wall and do screed work exactly, then you can eliminate the plaster and soil step and instantly execute the white plaster stage.
Important issue number 1: in the parts where Rabyts has been utilized (like walls and ceilings), we do not accomplish the plaster and soil stage, and immediately carry out the white plaster plasterwork step.
Staff and the time of plasterwork execution:
Plasterwork teams normally include one building plasterwork craftsman and journey man. Sometimes this team include couple of plasterwork craftsmen and one journey man. The craftsmen tasks are rubbing plaster on the wall and ceiling, using screed, and finally wall troweling, and the responsibility of the journey man is preparing plaster in the container and handing it to the craftsmen. If it is a larger project, then some numbers of different plasterwork teams can be used simultaneously. If you want to increase the work speed, you have to have a skillful underlay craftsman. One of the most tangible cases is the plastering of ceiling which requires more time. Generally it can be said that every building plasterwork team, including one experienced craftsman and one journey man, can execute the plasterwork with plaster and soil, by 40 m2, as well as 50 m2 with white plaster on Hebelex or block walls in a space with common height of 3 meters every day on average. But as it mentioned already, if the plaster spraying method is used, the work progression speed increases remarkably, as far as a plasterwork team can carry out the plastering of 300 m2 on a wall daily.
The equipment that are required for plasterwork:
Required devices for traditional plasterwork:
If it is necessary scaffolding, barrel, and board
Woody, steel or aluminum screed
The required devices for spray plasterwork:
Plaster spraying machine
Building plasterwork expense:
For the execution of underlay operation and the traditional surfacing (with white plaster, soil, and gypsum) in the plaster spray method, usually the same price of ten to twelve thousands Tuman is considered for every square meter. But the price of spray plasterwork materials is more expensive than the traditional one. Every package of spray polymeric plaster costs between six to ten thousands Tuman. Every package of spray plaster weights about 30 kg and it is enough of plastering of 3 square meters.
Plasterwork without screed work (only with trowel) has lower price, often the half of the normal price.
The optimum climate condition for a building plasterwork:
If you accomplish the plasterwork at minus temperature, plaster will froze and then spoil. But as you know this problem has some solutions such as the isolation of building doors and windows until the end of plasterwork operation and drying out of plaster, as well as using the heaters, and application of warm water for mortar preparation.
Building plasterwork maintenance
Once the building white plasterwork ended, avoid scratching or striking to the plastered surface. For better protection of plasterwork it is recommended using painting or wallpaper on the plastered surface.
Consecutive execution of building plasterwork
The executive steps of the plaster and soil operation is carried out after the following stages:
Internal and external wall making
Piping or hosing of building mechanical and electrical installations
Execution of Rabytes and dropped ceiling
After ending up the above mentioned operations, the building white plaster plasterwork is done. If you use knauf for dropped ceiling, you can carry out this after white plaster work. To prevent any probable damages to the installation hoses situated on the building floor, it is suggested that first accomplish the flooring. The time of ceramic work and the installing of windows and building façade is no so important. It means you can accomplish it before or after the building white plaster plasterwork. But pay attention that the work of every team does not bather the other ones.
The correct and professional method of building plasterwork accomplishment:
Always try to consume the high quality and standard plasters.
Keep in your mind that the best plaster for plasterwork is recently produced ones (if the storing procedure is correct, then it is possible to store and consume plaster even for a year). The old and watery plaster is not suitable for utilization. The plaster mortar that is old does not have the quality and adherence power of the fresh one.
For plasterwork projects, use the professional teams, the ones you have seen their work samples. Since the unprofessional teams perhaps cause to the reduction of work quality besides the further material waste, and therefore compensates their cheaper wage.
The plastered wall surface must be completely flat, smooth, plumbed, and free of any defects, which we can test this issue with putting a screed on the plastered wall.
The plastered ceiling should be entirely leveled and without unevenness.
Plaster must be extremely white in color after drying
After plaster drying it must not be hollow and never sink.
Avoid accomplishing plasterwork at minus temperatures.
The plastered surface must be tough and without any white powder after drying.
The metallic parts such as the doors and windows frames, columns, and braces most be painted with anti-corrosion composition prior to the plasterwork.
The metallic columns, braces, and the parts where heater pipes situated in walls, ought to be wrapped with wire netting.
In the joint of two walls with different materials, for example the brick wall connection with Hebelex or concrete ones, the wire netting must be applied to prevent the crack formation during expansion and constriction of two different materials.