- Solid plates (grades T, T-S, T-P, T-SP, T-V, T-SV, NT, ST, ST-S)
- Soft plates (brands M-1, M-2, M-3)
- Characteristics of fiberboard M-1
- The use of fiberboard for floor finishing
- Features of installing fiberboard on a wooden base
- Installation of fiberboard on concrete (screed)
- Operating fiberboard on the floor
In this article we will talk about the popular building material – fiberboard, consider the features of its use as a floor covering. You will learn about the differences in brands and installation features. The article contains information on the mechanical, consumer and operational properties of fiberboard for flooring.
Fiberboard is a fiberboard, which in modern Russian-language terminology is also called MDF (from the English MDF – Medium Density Fibreboard – medium density fiberboard).
It is produced by pressing ground wood material (ground sawdust, wood chips, shavings – natural fiber) and cellulose. Before molding (pressing) of hard plates, additives are added to the mixture:
- Synthetic resins for welding particles together.
- Water repellents (rosin, paraffin) to resist getting wet.
- Fire retardants and antiseptics.
- Pectol impregnation for hardening.
Soft plates of grades M-1, M-2 and M-3 are pressed “wet” – the raw material moistened with water is sent under a hot press – without the addition of additives.
The material has been known for a long time and is widely used in construction, household products, furniture production and packaging all over the world. Accordingly, for different needs use “their” grade of this plate. In total, twelve varieties of fiberboard are known, which in the context of this article can be conditionally divided into two categories.
Solid plates (grades T, T-S, T-P, T-SP, T-V, T-SV, NT, ST, ST-S)
Laminated fiberboard – pressed boards coated with finely dispersed polymer-wood pulp. It has relatively high strength and fire safety indicators. This is a well-known laminate or low-grade parquet board (6-12 mm). Thinner panels (3–5 mm) are used for wall and ceiling decoration. Furniture elements (facades), packaging, decorative items are also made from this material (it lends itself well to processing).
Soft plates (brands M-1, M-2, M-3)
It is this material that is the object of interest of our article. People often call it “hardboard” or “pressed cardboard” and there is a large grain of truth in this. Up to 60% of recycled material is used for the production of soft boards (sheets) – waste paper, wood chips, bark, used corrugation. It is widely used in construction, furniture industry and packaging..
Characteristics of fiberboard M-1
As a sample, we will take the optimal widespread version of fiberboard grade M-1 (GOST 4598–86). A distinctive feature – no glue or resins (biologically pure material) are used in its manufacture. Its indicators:
- Density – 400 kg / cu. m.
- Flexural strength – 1.8 MPa.
- Compressive strength (10% deformation) – 35 MPa.
- Tensile strength – not standardized.
- Thermal conductivity coefficient – 0.09 W / m ° С.
- Release form – sheets up to 3 m long and 1.2 or 1.8 m wide.
- Sanding, decorative (paint and varnish) or protective waterproofing coatings – on one or both sides.
As can be seen from the initial data, fiberboard refers more to insulation than to structural materials. For comparison, the thermal conductivity of polystyrene foam suitable for a similar application is 0.032 W / m · ° C. At the same time, the bending strength of the slab is significantly inferior to even relatively weak wood – pine (79.3 MPa). However, the fibers are not without reason formed in the form of a slab – this gives the necessary advantages for using this material on the floor.
The use of fiberboard for floor finishing
The shape of the sheet or slab allows you to easily and quickly level surfaces, bridging gaps and creating an intermediate preparation layer. The pliability and brittleness of the material when tested for bending, fracture and rupture do not play a role in this case – on the floor, fiberboard works in compression. In this sense, MDF is closer to wood – the compressive strength of pine is 44 MPa (versus 35 MPa for fiberboard).
With all the advantages mentioned above, one significant drawback does not allow its full use as a facing material for the floor – low density. It causes low abrasion resistance, which is unacceptable for flooring. Besides, soft plates are “afraid” of water and swell quickly when wet. Therefore, fiberboard M-1, used on the floor, must be well protected from abrasion and moisture, which leaves them exclusively as an intermediate layer. In this capacity, MDFs perform the following functions:
- Overlapping slots up to 5 mm. This is often used by unscrupulous builders, performing repairs “quickly”. The draft is blocked, but the floor remains cold. For good thermal insulation, be sure to check the gap filling before laying..
- Plane alignment. Fiberboard smoothes well the millimeter steps of the old floor board. This must be done before installing new flooring, especially linoleum. Otherwise, the step will appear on it and the linoleum will eventually break through.
- Noise isolation. Due to its softness and relative looseness, fiberboard absorbs noise and vibration. For this indicator, it is also appropriate to compare it with basalt wool.
It is also worth mentioning that fiberboard is a rather demanding material. It does not tolerate changes in humidity and is intended not just for interior decoration, but for residential and constantly heated premises. 10 cycles of significant moisture change will lead to irreversible warpage, even if the sheet is fixed.
Features of installing fiberboard on a wooden base
Due to its low tensile and shear strength, the plate cannot reliably hold the force at one point – the heads of nails and self-tapping screws push through the material. The small thickness of the sheet does not allow to make a sweep to hide the cap. Hence the conclusion – there are only two ways of fixing the sheet – with many small dots or with glue.
Multi-point mounting is an effective method, but rather time consuming. In this case, the sheet is fixed on small thin nails (12×1.5 mm) in increments of 100 to 250 mm. The nails create an even pressure on the entire sheet, and the force is distributed not over 20-30, but over 200-250 points. In addition, their small caps do not stand out on the surface of the fiberboard..
This method has one critical contraindication – a shaky foundation. If there is even a subtle backlash, it will surely result in a gradual release of nails from the seats and a rupture of linoleum. It is not possible to use self-tapping screws due to the size of the cap. The set of points method is relevant only on a wooden base.
Installation with glue. Fibreboard in the basic version (sanded on one side) is well suited for working with PVA glue on the rough side. The glue adheres perfectly to the wood surface. If you need to level the old wooden floor, it is better to use the combined method – grease with PVA glue and fix it on small nails. The cost of PVA glue is 1.2–1.5 cu. e. for 1 kg.
Installation of fiberboard on concrete (screed)
When installing on concrete or screed, there are nuances that must be taken into account in advance:
- The base must be flat, without drops.
- The moisture content of the cement base is unacceptable (it is blocked by special compounds – primers).
- An even pressure must be ensured.
- The concrete of the factory floor slabs has extremely low adhesion.
A subspecies of this method is mounting on a double-sided industrial tape, designed specifically for gluing wood, PVC, PPR to concrete. A bay of such tape, 460 m long and 12.5 cm wide, costs about 10 cu. e. (DK Film, DURACO, USA).
When laying on glue on concrete, it is recommended to arrange more than one layer – it is better to securely block cold concrete. The clamp can be organized as follows: lay the boards on the surface and fasten them with dowels to the screed (the sheet is already laid on the glue). After the glue dries, remove the boards, fill the mounting holes with liquid nails.
Operating fiberboard on the floor
There is an opinion that if you paint the fiberboard with enamel, it will make a good floor covering. This is not the case as the sanding surface has poor adhesion. In addition, the surface is sometimes covered with a thin layer of water repellent.
Even a sheet impregnated with a water repellent should be protected from moisture by all means. The easiest and most affordable is to impregnate the finishing surface with linseed oil (on which the finishing layer will be laid). The cost of drying oil is 1–1.2 cu. e. / liter.
Also, the material is well suited for rough filing of insulation (from the inside!), Especially mineral wool – fiberboard is vapor-permeable and allows the insulation to “breathe”. The plate is processed very easily – it is literally cut with a knife. The cost of fiberboard in the basic version:
- with a thickness of 2.5 mm – 1.5 cu eat2
- with a thickness of 3.2 mm – 2 cu. eat2
Oddly enough, but among the most modern materials, an alternative to the M-1 fiberboard has not yet been found. Manufacturers can only experiment with its composition, adding hardeners and flame retardants, and vary consumer properties. This cheap, lightweight and comfortable material is indispensable as an intermediate leveling layer when finishing the floor..