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  Restoration plasters or instant soup

That's what I write below is not and probably will not be popular, what's more - it will be contrary to what is given on the various meetings and leaflets.

The current restoration plasters plasters commonly used even 30-40 years ago (not to mention those taken with even just after the war) have to like soup cooked with fresh ingredients for instant soup which a multitude of shops. Only the name was not changed.

As already mentioned several times, at least plaster or rendering coat, are basically currently mortar based on cement, and hydrated lime filler. Sometimes, lime is replaced or assisted plasticizers. All in powder, all poured here and now into the mixer and mixed. Mortar, old and new, even ordinary concrete, sometimes you can only hear it, and so there's nothing like mortar based on slaked lime

Initially, the lime was burned and the end product was just lumps of lime, which had to be properly prepared for use. They were called to extinguish, which is initially solid pulverized, pouring water in sufficient quantities, would not she was neither too much nor too little. After some time, the received ready "slaked", lime usually in the form of a ready to use dough lime. Due to the length of such a process (in the last years, it was at least several weeks) constituted a problem.

As a result of technological progress formed hydrated lime or slaked dry, in contrast to the quenching structure - the wet, used for this minimum amount of water that was formed by the reaction of a dry powder rather than plastic, moist mass. Extinguishing process, which leads to a form of plastic, you can, of course, to finish the construction - it must last a minimum of 24 hours.

Personally, I have witnessed plastering mortar slaked lime, cement and filler. She acted like it better prepared mixed powder, ready for use. If so mixed mortar, so short slaked lime so strongly influences the mortar - it's like it was before?

Restoration of masonry, of course, different and cement-lime and pure limestone, usually concern renovation work on buildings listed in the register or under the supervision of the relevant conservator. This does not mean, of course, only the old, pre-war townhouses and palaces - such care can be surrounded by example. Some architectural assumptions, such as Nowa Huta in Krakow as a classic example of the construction of socialist realism, and several other styles.

Slaked lime can be stored pitted, covered with a layer of sand over many years, and what is interesting is not it loses none of its properties. Even in the 70s and 80s old bricklayers prewar date have used almost exclusively slaked lime. Widely available literature indicates that masonry lime enough to extinguish the "only" two weeks and plaster a little bit more, because "up to" two months. It seems that this is not a big problem during the construction, because the quenching process could begin with the beginning of spring. More detailed rummage on the Internet can decipher that the recommended period of "fire" of lime for use in the construction industry was one year. Today, exceptions are teams that are trying to extinguish, because otherwise it can not be called, hydrated lime, even this day or two. And if you do that, it provides only for their expertise and professionalism.

Only those statements regarding the 70's suggest that in the interwar period it had to last even longer. These words also help us to ask one basic question - how to present the mortar renovations to the ordinary mortar type c / w 60s or 70s produced based on slaked lime, cement and sand often secretly somewhere kopanego? The answer is simple - nohow. More or less like the VW Beetle VW New Beetle.

"Guide bricklayer rural" (Edition 1956) recommends that the use of lime plaster extinguished at least several months in advance, because only in this case lime will be extinguished completely. The hydrated lime mentions only that come in powder form. In the book "Rural Construction" from the late nineteenth century. It is written exactly slaking lime, about how much water should fall on the type of quicklime, about how to take care of it. Of course, between the lines it is mentioned that the process should take several months, as stated very clearly how to protect such pitted lime before frosts.

The guide "Rural Construction" 1917 minimum lime eating set at two to three months, but clearly underlined that it is best to extinguish the process lasted at least one year or longer.

As you can see, through thick decades since the end of the nineteenth century to the mid-twentieth century, lime slaking considered the primary means of obtaining lime pies necessary to create the perfect lime mortar, clay or cement-lime necessary for the respective expeditions. Although the specified minimum slaking for 2 weeks or 2 months, it is strongly emphasized is that the best lime is extinguished, ie those having at least a few months, and so seasoned. This phrase means a material that simply wintered. In the bottom of the appropriately protected.

Lime mortar itself should not be to hard (thus increasing the spread of the popularity of the cement, cement - lime mortars) and quickly hardening. The ancient builders could, however, work around this problem and in many different ways. Here, unfortunately, in the eyes throws decreasing with time the number and range of methods to change the relevant properties of mortars.

All this leads to a simple conclusion - according to the guides on the building, which was designed for both typical rural masons and masters profession, in principle, any mortar made of cement-based, cakes lime (or slaked lime / lasowanego) and sand (of course mentioned vary his grit, different composition) can be and is (!) mortar identical or similar to those used in the period when the building was built or was carried out the renovation, according to the trends (eg. in the 20s of last century) prevailing.

Instructive are studies before the invention of portland cement, or rather the rediscovery of the role it plays in the construction industry. Very interesting studies from the late eighteenth century. "Construction for the needs of rural farm ..." published in the last quarter of that century, repeatedly mentions the fall of the customs building, decay of knowledge, what was in previous generations. In addition to describing how to perform down / trench in which the lime will crumble clearly stated that the process of crumble lime must take several (!) years, that was really usable, the word good (!) can be used in relation to lime slaked at least three years.

This illustrates how far the current technology moved away from what used to be known and used. Even those three years is in some sense a curse technology that anything known previously tossed in the trash with the inscription redundant, while lightly treating those who are trying to use old knowledge, even to a limited extent.

Watching old plaster wonder that even a century later, the moisture in the walls, any number of floods, really they are still strong, peeling usually in those places where the impact of external factors is really prevalent.

This old, over two hundred years, entry mentions a few other types of mortars and additives used to change the properties of the same lime mortar, relatively weak and not binding. A common feature of the various methods is to add organic materials - skull, blood beast, hair, skin (some studies explicitly mention truchłach animal) etc. added to the bottom of the lasującym lime. After a few years it turned out that not finding any of these supplements, but she lime mortar was strong, strong, and resistant to moisture. He created in the process of eating strong glue casein.

The then experts in the art also know how to create lime mortar masonry under water. It is created on the basis of slaked lime and quicklime and several other additives. Below the original recipe:

1. Take three parts of fine sand and well-scrubbed, three parts of tile or brick finely utłuczonej and well burned, the two parts of slaked lime and quicklime two well shattered and blown again, either all the same. Mix first well slaked lime, sand and brick, then top up the water slowly as mixing, according to art.

2. Prepare the lime on the dust grated, sifted through a sieve and add to the previously prepared mixture.

3. Preparation of a blend of already slaked lime bricks and sand dissolve in the water to become quite rare, which was then stirred until it becomes a single mass.

4. After that add about quarter of the quicklime and screened through a sieve and mix properly..

5. All this mix begins to burn and fade right away, which means that in order to completely dry, it should be used within half an hour.

6. Use should gracy iron, and the same lime must be ground in special mills for grinding quicklime is harmful to humans. Alternatively, you can grind in water mills or operated by animals. Of course, the lime must be of the highest quality. The essence of this method is the correct addition of water, because it depends on it, whether the mixture is appropriate.

The author pointed out that eg. four pounds of slaked lime and ordinary require ten pounds of water, and if you add quicklime and pounded into dust - should add another five pounds of water, then it should be as soon as possible to mix and use. The author outlined, that the walls, stones or bricks should be wet and in any case can not be dry.

What does this really mean? This description and a whole bunch of other usually confusingly similar to each other is a signal that what today is a mortar Restoration, which should meet a whole bunch of recommendations, comments and have some odd properties when the current monument was built or renovated was typical of lime mortar or cement -wapienną, made according to the canons of contemporary art and knowledge dating back to the old days, when quenched lime several years (and in later years a minimum of one year), when the cement was the cement-based clinker, and its numbering and related properties were intended (!) and no amount of additives such ash, or rather how little clinker was ...

This means, as was repeatedly emphasized that almost every plaster made on site, using old techniques - that is, slaked lime, very good and very clean in terms of the composition of cement, fine sand - a plaster refinishing. This statement is all the more justified, that it really renovation plasters produced or manufactured today have exactly the same tasks that meet the plaster in the past, but this is achieved using a shortcut (as mentioned already evident in previous articles concerning the renovation plasters).

These "shortcuts" are caused by:

  • poor quality of cement (high content of alkali, a large amount of ingredients other than clinker
  • another type of lime used currently (hydrated before forests), which is also related to its quality, purity and properties
  • conversion of some of the components (lime) to another (so-called. chemistry), wherein this conversion generally refers to a substantial part, or even a whole. That substitution enforces the use of chemical additives with another task, not just a plasticizing mixture (lime in the mortar acted as disinfectant, to prevent the occurrence of fungi and others like them)

Interestingly a similar, negative evolution undergone production of bricks - formerly one of the basic building blocks used for centuries. To this day, I was surprised to be met with the stories, like the nineteenth-century brick or older sounds, about the fact that it is smooth and basically do not move ..

In theory, the production of bricks is simple, and to present the same process of production from extraction of clay, its fragmentation, purification from impurities and unnecessary components after adding water and burning is quite short. In many publications, the information about hand-molded brick mentions only the different process of forming the bricks and the possibility - by virtue was manually form of - shaping of various sizes, shapes or dimensions. Oh, hand crafted.

But just to go back to the pre-war period, to understand how far been simplified and neglected not only the production process, but just to prepare material for firing - as the "production quality" has been "some production".

Interestingly, in the aforementioned book on rural construction author points out that throughout the country (author has in mind Poland, can assume that rather within the interwar) we have essentially good or very good clay. In the description of the production of bricks notes that the same clay should be "dug up in the autumn," and then deposited in mounds to atmospheric moisture and winter frosts have helped her decay, or make split from the dangerous later in the production of materials, for example. Marl. This principle confirms the position slightly older (late nineteenth century. For rural construction), where you can read it, that bypass the process of "decay" clay is possible, but the consequence that in principle it is not possible to get rid of any impurities from it. Further production steps so as to mix the clay with water of winter and molding the mixture (of course, with the addition of the necessary ingredients, eg. Sand) bricks from the pre-forms. They were then placed on the square (or properly prepared worlds) to dry. Only after this stage, it followed by burning brick lasting several days.

Position 1917 notes that a well-burned brick, with well-prepared mixture should be during the strike to sound, can not be deaf.

Yes scratched course briefly the production process means that it really time brick production from extraction of clay from the deposit until the sale of bricks, made from the same clay can be assessed at a minimum (!) One year, and probably about one and a half, because the brick after firing too slowly cooled down, gathering relevant characteristics and appearance.

Long from our modern point of view of the production process meant that brick, which came to the construction site, then serving masonry massive objects (eg. The Austrian forts, even some of the buildings on Wawel Hill or houses) even today it is in excellent condition. Looking at it from a distance you can not see white streaks - taking both of poor quality mortar used for masonry as well as the pollutants that includes a burned brick (eg. those marl).

This means that the poor quality of the material used for construction or patching does not help even the most demented types of mortars. For nothing, they were reputed, when in fact today brick having the highest quality and fulfills all the conditions of today's hundred years ago would have been regarded at best as waste.

About how much has been simplified technology of brick production in the late nineteenth and early twentieth century (about the present time not to mention) provides already cited the position of the eighteenth century. Interestingly, the word contained in it, highlight the semi-legendary, passed sometimes through anecdotes stories that Jewish producers of bricks require that at least one generation has passed in order to be able to transform the clay in the brick ... You can read it, that former years (the former in relation to the eighteenth century) clay for brick protruded and seven years (emphasizing that this period was the same as for lime), and the brick already in the forms was drying years, a minimum of two, and the best was a brick of clay formed in the spring and summer. The collapse of the customs and art of building block is noted that at times the author of today's most common clay was gnojona only through two winters and two years, which translated is usually two and a half years to three calendar years (assuming that the kneaded was during wiosennoletnim ). Of course you mentioned that you should not regret water in the dry season to better rotting clay (the author called it maceration). A few days when the clay was well prepared for the decay process (fragmentation getting rid of impurity) did not affect its length.

About such an important detail that everyone basically kind of brick was not only his clay, but at times, and drying time do not remember, because it was clear. The method of firing was also different, ba - author recommended that because of this, that each batch of clay may differ from each other gently, first try a small batch of how it will behave oven, how you will react dried brick on the production process. The same cooling of bricks in a well-sealed furnaces should last at least nine days. Of course, the clay can be mixed with various additives to modify and change the properties of the bricks in one or another direction we desired.

Another publication from the same period - only a few years later, dedicated to the construction of a brick factory, also gives a description of how it should prepare the material for bricks. Time gnojenia clay was determined for several years, with interesting information that can be found in the old court file (again, the decay of morals ...) processes strichars (people involved in the production of bricks), who macerated clay less than five years ...

That's all it really means that from extraction of clay for the production of the brick should take at least several years, and two or more decades will not be uncommon. The latter two items mentioned agree that the longer the period of preparation of clay, drying them calmer, the better the brick, the less absorb water, the more resounding.

It is for these reasons that the old plaster hold on tight, do not want to fall off the brick, which looks as if it had just been created; This is because cement-lime plaster already somewhat later may be dirty and gray, but did not meet them efflorescence; This is because only detrimental environmental impact (pollution - the bulk of these buildings has had a period of rapid industrialization in the late nineteenth and early twentieth centuries, the period of the 50s, when every black sooty chimney was clearly associated with technological progress, and each ton of coal march towards a bright future ...) made the plaster began to fall and decay ...

Reading and wondering how far changes have occurred not only in the quality of materials used to build houses, but also how it should be done, begs the basic question, which is how familiar - why not take advantage of the currently available best ingredients that you can have and not mix plaster as once? If you can buy cement the typical parameters of the 20s, if you can put out lime "initially" prepared for this, mix with sand so common and well-known for a long time proportions? What is the difference in the properties - no difference in relation to the previously applied plaster - certainly much less than the current restoration mortars, and unparalleled superiority - price, simplicity of execution of the same, and the possibility of modifications to the finished material - priceless.

One of the criticisms that can be heard is that they are ready plaster en-route, containing a trass. And what will we differ, mixed mortar here and now, if we replace the usual lime lime-route? Nothing, and so will its composition of cement quality years old, and so you will be able to do it exactly the same as "an ordinary mortar," just "adjust" its properties. Price and so will still be several times lower ...

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