What is shell rock?
It was not for nothing that they gave it such a name: the porous shell rock was formed from the shells of the inhabitants of the seas - molluscs, they were pressed with calcite cement into a single rock for many millennia. Therefore, if we talk about the beneficial effect on humans, then this type of limestone is significantly superior to other natural stones, even semiprecious ones.
Rakushnyak deposits are located in those places where in ancient times there were huge oceans and seas. Now these are the coastal regions - Crimea, Krasnodar, Stavropol Territory, Rostov Region, Dagestan. If we talk about the post-Soviet space, then shell rock deposits are located in Azerbaijan, Kyrgyzstan, the Baltic States, Ukraine (Odessa region), Moldova, Turkmenistan. This prevalence of fossil deposits is the reason for their widespread use.
The age of the material is hundreds of millions of years, so the stone has been used for the construction of houses since ancient times. Now it is chosen for the construction of walls of low-rise buildings or outbuildings, for the creation of gazebos, fences, garages, for the construction of fireplaces or arches. Its decorative properties are no less popular, giving a chance to use the stone in a different capacity. For example, interior or exterior decoration of a house with shell rock will make the home cozy, warm, unique and comfortable.
How to choose a quality stone for construction work
It is necessary to visually evaluate each stone for the presence of open pores, and also pay attention to the severity of the limestone - an instance with a weight of at least 16 kg is suitable, since it differs in a rather dense structure and small porosity. Do not neglect a thorough study of the material quality certificate.
The surest way to assess the density of a shell rock is to hit the rock hard against a hard surface. The number of pieces into which the mineral will scatter after impact objectively testifies to its qualities. So, no more than three broken pieces indicate a dense shell rock of the M-25 brand.
The stone of the M-35 brand cannot be broken in this way at all. The higher the density of the natural material, the less lumps and sand will be obtained as a result of the impact.
How to choose?
The choice of shell rock should be approached as carefully and responsibly as possible. You must remember that the building material plays an important role and has a great influence on the final result of construction work. One way or another, when choosing a material, you must adhere to the advice and recommendations of specialists.
Appointment. First of all, you should think about the purposes for which you will use the stone. So, for example, if you are going to build a small house (1 or 2 floors), then you should choose the M-25 brand. For more reliable and durable structures (for example, a foundation), choose the M-35 brand. Variety M-15 is often used for interior partitions.
Appearance
In the process of choosing and purchasing a stone, it is very important to make sure that the shell rock is intact, does not have chips or any other defects. If there are any, it is recommended to cancel the purchase.
Place of purchase
To buy shell rock, contact specialized hardware stores. For guidance and advice, consult a qualified sales consultant.
Basics of shell rock construction
When designing a house from natural material of sedimentary origin, it is necessary to take into account the features of shell rock structures.
Foundation
Shell is a relatively light material, but requires a solid base.It is ideal to put a foundation made of reinforced concrete tape or piles - such foundations practically do not "lead" when the soil expands. The main rule of a shell house is that the walls should be as high as possible on the ground so that the rock does not absorb water. The minimum plinth height is 40 cm.
You should not use shell rock as a material for building a foundation - you will need expensive waterproofing work on the inner and outer walls of the basement.
Walls
External and internal walls of shell rock are assembled like aerated concrete blocks. They are laid in one or more rows, depending on the accepted thickness of the structure with bandaging the seams, sometimes reinforcement is used. Masonry is carried out with a lime-based solution - such a solution holds the stone better.
Correctly selected thickness of shell rock for wall construction eliminates the need for additional insulation. Brick cladding can be used as a protective facing layer. Such a wall is built in the same way as a multi-layer one - several rows are erected in parallel with periodic dressings.
Jumpers
The lintel over the window and door openings is a concrete beam. However, a shell rock house can be built using supports made of the same material as the walls. The choice is always up to the developer. It should be noted that a concrete lintel is capable of withstanding significantly higher loads than a shell rock lintel.
A prerequisite is that the beam must be reinforced with two rows of reinforcement with a diameter of 10-12 mm, if the construction is carried out without precise structural calculations. The concrete cover should not be less than 2 reinforcement diameters.
If lintels are chosen from shell rock, for these purposes it is necessary to use a dense stone. The beam is arranged from several fragments of a wedge-shaped structure.
Roof
For a shell rock house, pitched roofs of any configuration and size should be taken, the main requirement is the organization of the maximum drainage from the unprotected facade, the device of drainage gutters.
Finishing
Shell is a porous material and, as already mentioned, absorbs water well due to its high porosity. This must be taken into account when choosing a finishing method. The materials must resist the penetration of water and moisture. Plaster mortars and facing with bricks and stones will help to cope with the task.
Why is it better to plaster walls made of shell rock: for protection and cladding, ordinary cement-based solutions or decorative plasters for facades or interior work are suitable. Due to its high porosity, the coating adheres well, adheres well and lasts for a long time. It will not hurt to clean the blocks of dust before work and prime them with soil of deep penetration into the stone.
The use of shell rock
Due to its exceptional qualities, this natural stone is simply irreplaceable both in housing construction and for other purposes. But there are several nuances that you need to know. Due to the difference in density, strength, color, structure of shell rock, when buying, you must look at each block for through holes and check the brand of the product. The brand is easy to check for impact: how much the block will crack.
The weight of the block must be at least 16 kg, as a guarantee of the required strength and density. The most extensive application is, of course, in the construction of houses. Blocks with an untreated sawn surface can be used in the construction of walls, fences, arches. Low thermal conductivity of shell rock walls will provide the room with comfortable warmth in winter and refreshing coolness in summer. For areas with an average climate, a wall width of 40 cm is sufficient. This material is "breathable", so excess moisture can easily evaporate through it, the house is always dry and optimal air humidity is maintained. This prevents mold from forming. Good sound insulation will not allow street noise to distract you from enjoying your vacation.The healing properties guarantee improved well-being and good mood.
The strength and inertness of the stone are the key to the durability of the building. There are many architectural monuments in history, built of shell rock and preserved in excellent condition to this day.
The porosity of the surface contributes to strong adhesion to concrete, and the layer of mortar can be minimal, practically seamless masonry. And this again has a positive effect on the cost of construction.
Thanks to the large size of the blocks, it is easy to work with them: you do not need such skill as when working with bricks, you can do it yourself. It is enough to set the level correctly. You can put it on any foundation, there are no special requirements for it.
Another plus in favor of shell rock: the block can be easily cut into pieces of the required size with an ordinary grinder with a circle of at least 180 mm. They will be required at the junction of walls and floor beams, in door and window openings.
Shell rock tiles are ideal for outdoor facades. Low weight does not create additional load on the foundation. Its polished surface does not need additional processing.
The natural color is in harmony with the surrounding nature. Before cladding, the walls also do not require special preparation: the high degree of adhesion of the shell rock to the concrete guarantees reliable fastening to the facade and hides its irregularities. Only for concrete mortar it is necessary to use fine river sand. If desired, the slabs can be easily painted in any color. The porous structure absorbs paint well and for a long time.
Polished slabs are also used in interior decoration, fireplaces and stoves. Ease of sawing allows you to give fireplaces any shape and shape. Low thermal conductivity will provide pleasant warmth to the outer surface of the block, despite the heat inside the hearth.
In areas with high humidity, frequent rains, heavy snowfalls, after the completion of construction, the walls must be treated with waterproofing agents, or cladding made of wood, brick with a gap for ventilation. You can also use mineral wool insulation or vapor-permeable plaster. If a road passes next to the house, then you can treat the facade with a special compound that prevents the settling of combustion products. There are also remedies for those who like to paint on the walls.
Various decorative items can be cut from shell rock: sculptures, flowerpots, various stands.
The unique pattern of curls of shells on the cut will add elegance and lightness to the products. Having treated the surface with a protective compound, you can provide them, without exaggeration, eternal life.
The rough (cobbled) surface of shell rock slabs is resistant to abrasion and therefore is used for facing steps of stairs, porches, paths, areas inside the courtyard. Where it is necessary to reduce or completely eliminate slip.
Summarizing all of the above, shell rock is an excellent material for creating a beautiful, reliable and comfortable home for years to come.
Disadvantages of shell rock and how you can fix them
Shell rock, having its own advantages, at the same time is not an ideal building material. It has a serious drawback - this is heterogeneity. In the quarries for its extraction, there are various layers of rock, which do not have the same porosity. In this regard, there is a risk of getting a material with different characteristics, especially different thermal conductivity. This indicator influenced the lack of it on sale in hardware stores. However, this is not a reason to abandon it as a building material. You can always choose blocks with equal indicators from the offered assortment, it is enough to know how to do it. Basically, specialized companies trade in shell rock. They also deliver material to the place of work.Finding a supplier of uniform shell rock is impossible, as this problem is common to all companies selling shell rock materials.
The negative qualities of the block heterogeneity are through pores, due to which the thermal conductivity is sharply reduced.
The erected wall of such material is blown through. To eliminate this disadvantage, you can use two options. With the help of the first, we choose a high-quality shell rock. We inspect the material for the presence of through pores and determine the weight of the block. A stone satisfying normal characteristics should weigh more than 16 kg with a dense structure and medium pores. Good suppliers sort the material themselves and provide a quality certificate for the product. But you should still check the blocks. A block made of shell rock of the first grade, grade M35, does not split when hit on a hard surface. The M25 block should not split into more than three parts with the same impact. The correct shape of the block with the same dimensions, high density and uniform structure testifies to the quality of the product. Due to its natural porosity, shell rock has a high degree of moisture absorption. Therefore, the walls should be waterproofed by covering with a special solution. Facades of buildings finished with shell rock and located in a place of heavy traffic should be treated with oil-hydrophobic agents.
Biological and chemical compounds can be used to protect shell rock.designed for this.
The second option is to eliminate the consequences of material heterogeneity by erecting an external barrier, finishing with vapor-permeable plaster or making a ventilated facade. You can insulate the main walls using thermal insulation with vapor-permeable properties and then finish any type of facade ("wet" or "ventilated"). The wood-type ventilated façade is one of the most advanced and environmentally friendly methods used to protect shell rock walls. During construction, load-bearing wooden beams are pre-assembled into the walls. On which the planking is subsequently attached, leaving a gap for ventilation.
Composition and main characteristics of the material
Shell rock is a limestone composed of calcium salts. Moreover, regardless of the place of extraction, the composition remains approximately the same: calcium carbonate - 52.06-55.66%, magnesium oxide - 0.19-0.71%, carbon dioxide - 41.16-43.62%. Under the influence of acidic water, calcium, which is part of the shells, decomposes, releasing carbon dioxide. This determines the presence of pores in the structure of the shell rock and the emergence of mineral springs. The main color is white-yellow, light yellow. Depending on the presence of impurities, the color may be different: iron gives the shell rock pink shades, copper - blue, coal - from gray to black.
Due to the fact that the shell rock was formed in the places of the former seas and from the remains of marine animals, it emits vapors of iodine and sea salt, has good antibacterial properties. In a room decorated with this material, a specific composition of air appears, strengthening immunity and strengthening health in general. It especially helps people with cardiovascular diseases and those who have problems with the upper respiratory tract, with the thyroid gland. Many resorts in the world are known for their coquina beaches with healthy air.
Shell rock is a natural stone, therefore it is an environmentally friendly material. Compared to others, it has a neutral background radiation of 13 μg / h, with the minimum allowable level of 25 μg / h. At the same time, it perfectly protects against dirty air, radiation and other harmful radiation by 100%. This is the only material capable of this.
Another very important advantage over other building materials is that mice and rats do not like a shell rock house.For a country house, this is a significant indicator.
The presence of pores is the reason for the low thermal conductivity of shell rock - 0.2-0.6 W / m-С °, while in brick - 0.55-0.64, more than two times more. The situation is the same with soundproofing. Therefore, the use of this material eliminates the need to additionally insulate and protect the walls of the house from noise, which gives significant savings in construction. In addition, the shell rock has a very high frost resistance - up to 70 cycles, so you can not be afraid for the integrity of the exterior decoration of the walls of the house, unless you go to change it yourself. Shell rock is very inert, therefore it does not react with other building materials, therefore, it will not collapse on its own and will not deform other substances.
According to their density, three brands of shell rock are distinguished:
M15 is the least dense, with large pores, very loose in appearance. It can be of different colors - from white to brown, but most often yellow, for which he received the nickname "yellowish". The yellowish tint is given by the presence of impurities of sand, which has a higher thermal conductivity compared to the shell rock itself. Therefore, this brand is the coldest among other brands. When hitting a hard surface, the M15 block breaks up into several parts. By weight, these blocks are the lightest (8-12 kg), therefore, during loading and unloading operations, their surface may be disturbed. Subsequently, in order to level the surface, it may be necessary to carry out a large amount of plastering work. Despite this, it is successfully used in the construction of garages, utility blocks, fences, baths, upper floors.
M25 is a shell rock with medium density and porosity. The main color is light yellow, sandy. If dropped, it rarely breaks in half, even less often into three parts. The most popular brand in construction, as it surpasses brick, gas and foam concrete in strength. It is widely used for the construction of two-three-story houses. In frame and panel construction, interior partitions are placed from this brand of shell rock. Block weight - 14-17 kg.
M35 is the densest and strongest grade of stone, has the lowest porosity. The color is almost white, yellow-white. The heaviest of all brands (22-25 kg), therefore ideal for laying a foundation, basement, basement. White shell rock is stronger than yellow shell rock.
Characteristics and properties
Like many other building materials, natural shell rock has many unique characteristics. It should be borne in mind that such properties are both positive and negative. Before purchasing and using the material, you must carefully evaluate all the pros and cons.
First of all, let's look at the benefits of a limestone stone.
Ecological cleanliness. This characteristic is one of the most important. Due to the ecological purity of the shell rock, it can be used to build a variety of structures, while they will not harm the people living in them.
Inertia. This chemical property of the material indicates that the shell rock does not react with neighboring substances. Thus, you can use any other materials in conjunction with shell rock.
Long service life. Quite often, shell rock is used for facing and finishing stairs, terraces and other common areas. First of all, this is due to the fact that the stone is very dense and hard in terms of its properties, it is resistant to the negative influences of the external environment. In addition, shell rock is resistant to high temperatures.
Safe composition. The composition of the material includes components such as iodine and salt, which not only do not harm human health, but, on the contrary, have a positive effect on it (for example, strengthen the immune system, eliminate signs of stress, increase energy levels, etc.). ).
Noise isolation.Due to this property, shell rock can be used for the construction of buildings for any purpose.
Simple processing process. You do not need special knowledge or skills to process shell rock. The material lends itself even to a beginner - it can be quickly and easily cut into slabs of the size you need (you only need a hand saw)
It is also important to note the fact that you do not have to carry out additional processes to level the outer surface of the material. This can be done with a bonding mortar.
Radiation resistance
Shell rock is a strong and reliable protective barrier against radiation.
Porous structure. Due to the presence of this property, the shell rock will protect the room from the appearance of dampness. The porous structure prevents moisture from retaining inside the stone.
Affordable price. The budgetary cost makes shell rock an affordable building material for almost every person.
Despite the presence of such a large number of advantages, it is also important to note the existing disadvantages of the material.
Fragility. In the process of transporting, storing and using shell rock, you must be as careful and attentive as possible. This is due to the fact that it breaks and collapses rather quickly and easily.
Low bearing capacity
In this regard, you should use stone with extreme caution if you are building a building with several floors. In this case, builders usually use a special armosh, which is a wire mesh and a cement mortar screed.
Inhomogeneous structure
During the buying process, special care should be taken to buy stones from the same batch. This is due to the fact that shell rock from different batches can have different characteristics and composition.
According to the standards that are spelled out in such an official document as GOST, the material should include the following components:
- calcium carbonate is the main one, its volume fraction should be at least 52%;
- magnesium oxide affects the color of the stone, its content in shell rock varies from 1% to 2%;
- carbon dioxide forms a special porous structure of shell rock and makes up about 40% of the total volume of the stone;
- additional impurities (this category includes coal, iron, copper and other components).
The usual size of a stone is 18 by 38 by 38 cm. At the same time, weight indicators may vary depending on the brand (the minimum value is 15 kilograms). It is also worth keeping in mind the fact that the shell has a seamless texture. The density index is 2.1 grams per cubic centimeter, and the thermal conductivity is at the level of 0.3-0.8 W / m per K.
Scope of application
Shell rock has a similar origin to marble and limestone. The only difference is lower density. At its core, the material is pressed shells of molluscs and is a porous stone that can be easily processed. Natural shell rock is presented in many colors, ranging from white to light brown tones.
The scope of application of shell rock is very diverse. You can build from a stone:
- load-bearing and attic walls;
- partitions in living quarters;
- outbuildings;
- fences and retaining structures;
- flights of stairs;
- front entrances;
- various decorative elements (cornices, arches, curly window sills).
With the help of shell rock, internal and external decoration of brick walls is made. It is used in landscaping and as a grout filler.
The material can be used to embellish steps made of concrete. Moreover, the price of such finishing with shell rock is much lower than the use of other natural stone. The only thing that is prohibited from building from shell rock is chimneys, stoves and fireplaces.
