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Fiber cement sheets are consisted of cement and reinforcement fibers and are one of the modern buildings requirements.

  • As cement became popular in building industry as well as its extensive use, cement facades became very popular as well.
  • Since the invention of pre-constructed buildings the idea of fiber cement sheets became stronger because it could be produced at the factory and delivered to the project site to be installed.
  • Considering the weakness cement has in bending and tension strength, the idea of reinforcing it was always discussed. In the late 19th and early 20th century an Austrian engineer by the name of Ludwig Hatschek used asbestos fibers to reinforce cement and build a machine modeled after the paper production machine which injected regular dosses of asbestos to cement dough and produced an excellent material with exemplary qualities by the name of flat asbestos sheets or corrugated cement sheets which was produced and used in all  countries for the past century.
  • Since the last decay of 20th century, considering health and environmental factors, the ban of asbestos use was instructed in international communities. Fiber cement producers decided to  find a substitute for asbestos. The result of the researches by the name of N.T (new technology) was launched and asbestos-free fiber cement sheets were produced.

Fiber cement sheets or boards are produced by Hatschek and the most important difference between them and the old production method is in the materials used, the processing and the technical science involved.


The difference between the flow-on method and the screen tank production method is in the process of material production on the felt. The concentration of watery materials in this machine is higher and the solid containments of watery materials is more which are directly transferred through the transfer mechanism.

Advantages in comparison to screening tank:

  • The production machinery is simpler and requires less investment.
  • The volume of returned water is lower and the machinery is simpler and takes less space
  • Watery material can form with any kind of accessible fiber and material and there is no special treatment required for keeping the fiber
  • and the matrix on the felt. This is why the production is without complication and easy to do.

Disadvantages of this machine:

  • The vertical and horizontal distribution of fibers is not done properly compared to the screen tank method.
  • Due to the fact that in this machine the layers of the product are less than the screen tank method the strength of products produced in this method are less than products produced by screen tank method.
  • High risk of layer separation due to bigger layer thickness and less resistance against bad geographic situation compared to products produced by screen tank.
  • The production volume is lower than the dual screen tank.
  • High risk of density difference in sheet.

These are the reasons that few fiber cement producers use these method although its simpler.


The purpose of cellulose preparation, is the production of high flow cellulose in order of fiber expansion without fraction.  This means that the fiber after the expansion becomes thinner. Liquid limit of cellulose is measured by a Canadian Standard, Freeness method or C.S.F, according to the ISO 5267/2 standard with the measurement unit of ml and the Schopper Riegler method of SR according to the ISO 5267/1 standard with the measurement unit of degree or (°). The extent of expansion required is a function of production type. (Flat sheet meant for inner use, flat sheet meant for outer use and corrugated sheets)

Without the appropriate expansion, cellulose fiber has the below disadvantages:

A: fibers are too big and rough to use beside cement. In this situation the tensile strength of the product is low and does not have the necessary area to ensure the ultimate tensile strength in fiber cement sheets.

B: The rough and big fibers can’t keep the necessary amount of water in the screen tank. The mesh cracks of the screen tank is bigger than the cement pieces, sillies and other extra materials. So the big fibers can’t stop the escape of these materials and a large portion of these materials exit the screen tank and cause a considerable amount of trouble in the water cycle use.

C: the excessive amount of cellulose in the plasticity production process causes a decrease in the quality. For example resistance against freezing of fiber cement products can decrease, also particle separation and cement parts from the fiber cement area can occur and cause some problems for the color coverage of the product.

Baverce co. cellulose production process is equipped with the below machinery to prevent the above problems:

  1. Water tank is equipped with water volume controller
  2. Cellulose feeding system including elevator, equipped with load cell.
  3. Cellulose pulper with 8 cubic meter velocity and 75 kv power
  4. Cellulose evacuation pump from the cellulose pulper (Centrifuges type).
  5. Two opening cycle tanks or refining cellulose fibers.
  6. Trash rack
  7. Refiner feeding pump, mohno type, with consistent discharge rate.
  8. 250 kv disc dual refiner to open or refine cellulose fiber
  9. Dual cellulose processing tanks with mixer, by the velocity of 100 cubic meter.
  10. Cellulose transition pump to material building section.

Cement boards, after completing grasping and curing process, have higher moister than the environment and after being exposed to the dryer, loose some of their moister and have a minor shrinkage and a minor reduction in their dimension like most construction material. So if the cement boards are not properly dried or in other words, their moister has not been reduced enough, after being installed in the structure and being exposed to the fresh air; lose some of their moister and the wrenches attached to the boards cause shrinkage or convexity or concave. This can cause internal tension and lead to cement board rapture from the wrench installation points and cause fracture from the edges of the board.

This is why the cement boards need to be dried and have their moister reduced to an acceptable amount to stop this flaw from happening.

Considering this problem baverce co. has designed, manufactured and launched an oven dryer to place its productions in before delivering it to the customers to prevent such problems occurring before installation.


The process of fiber cement board grasping is as follows:

1) Grasping in free air:

In free air grasping system, cement hardening and hydration bounds are formed in free air, as in other cement based products. After 6 to 10 hours from the time that sheets crossed through the heating tunnel with the approximate temperature of 50 to 60 degrees and the moister of nearly 100% the products have the appropriate strength for movement. The products are separated from the mould and are placed for at least 21 days in, damp free air inside a lidded space to reach their ultimate strength. In products produced in this manner poly vinyl alcohol (PVA) fibers ensure the arming of cement to ensure the tensile strength of the product.

               2) autoclave grasping:

               autoclave process causes basic changes in hydration materials for example high temperatures causes crystal shape silicate hydrate structures. In fact, the grasping system in free air, silicate hydrate crystals are formed but in very high temperatures in autoclave method the crystal structures are changed and the tobermolit structures are formed and can cause an enhancement in the sheets properties. In this system the cement is mixed with sillies with the approximate ratio of 40% cement and 60% sillies. The initial set is like the previous explanatory method in heat house but the ultimate grasping in autoclave and in the approximate temperature of 180 degree and saturated environment is set by the vapor pressure of 12 loads in which the silicate hydrate is formed. The crystal structure formed gives the product good physical properties which it has tensile tension and so the use of PVA is eliminated. The product produces in autoclave method and after passing the dryer is ready to be delivered to the customer.


Bedding of installation of ivanet flat sheets:

  1. Wooden or steel beams used for installation must be up to the common code of building construction
  2. Beams must have necessary mechanical properties.
  3. Frame case supporting the flat sheets must be connected to the celling or the floor and the sheets should not tolerate any load because of this connection.
  4. Maximum distance for inner or outer walls for beams is 600 millimeters
  5. Bedding beams should be made in a manner that the edge of the sheets can be placed on them and be completely supported by them.
  6. Width of supporting beams should not be less than 38 mm.


To install glazed tile or earthenware (for bathrooms) on ivanet flat sheets below conditions must apply:

  1. Colum beams distance must be decreased to 400 mm.
  2. The distance between horizontal beams must be below 900 mm.
  3. Inner and outer edges and the surface of the sheets must be covered by water-proof concrete caulk
  4. Before installing glazed tile or earthenware make sure that the surface of the sheets are clean and doesn’t have any dust or oil on it.
  5. Use special glazed tile paste and apply it one meter at a time.
  6. Push the glazed tile on the paste to eliminate any air bubbles that may occur in the paste.
  7. The special paste must be made and used according to the instructions made by the manufacturer
  8. To install bathtubs or shower-bathes act according to below details



Method of installation and adjustment of avanet flat sheets in the façade of the building:

  1. Its recommended that the seam between the sheets on column and horizontal beams be alike or in other words aligned.
  2. It is recommended that the width of supporting surface of the sheets be at least 75 mm so installing wrenches in 20 mm of the sheets be possible.
  3. Horizontal Framing for 10mm flat sheets the maximum distance for horizontal beams must be 800 mm and for 12mm flat sheets it must be 900 mm.
  4. In Vertical framing the maximum distance for beams must be 600mm.

Vertical framing method: 1- seam between sheets 10mm 2- width of supporting surface must be at least 75mm

Horizontal framing: 1-seam between sheets 10 mm 2- the width of supporting surface must be at least 75mm


Ardoise is a French word with the meaning of Fine – grained metamorphic rock which is made as a thin layer and sheets with smooth surface.

eyvanit Ardoise is produced by undergoing a pressure of 100 to 150 kg/cm² on its surface to be compressed and gain the same properties as natural Ardoise and for this reason mechanical properties and resistance against weathering is more than flat sheets and is closer to the properties of natural rocks.

Ardoise is a light coverage, impenetrable and beautiful that gives a classic look to villas and the façade of the buildings with high gradient.

Ardoise is carefully cut and hole-drilled to decrease installation time.

Ardoise installation tools, packaging details and properties:

Dimensions: 300by600 mm

Thickness: 4mm

Flexural strength: 220 kg/cm2

Number in a box: 10

Number in a pallet: 1020

Number used to cover 1 m2: 17

Number of truss or girder under the frame work: 900 mm

Framing distance under the foundation : 200 mm

Dimensions of wooden beams under the foundation: 30by40 mm

Required fastener: 2 galvanized nails and 1 crampon

Installation details of Ardoise avanet