An interior change can always start with a new floor that will bring a different breath to the overall decor. Wood is a warm and friendly material and the presence radically changes the air in a room, making it more welcoming and more open. Laying the floor is not a difficult process, and if you adhere to some basic rules, the much-needed change can be a successful one. Below you will find some technical details about mounting the wooden floor.
It is advisable to mount the floor when the renovation of the room is complete (this is the case for general cleaning), and the plaster, screed and screed must be completely dry. Specialists recommend a minimum of 60 days from the end of painting before installing the floor. At the same time, the heating and ventilation systems must be fully operational, maintaining a constant temperature in the 15-16 degree room and a relative humidity of 30-50% for at least five days prior to installation. Store the planks for the same period in the interior space where you will mount the floor.
A very important aspect in this process is the floor support surface, which can be a cement screed or a wooden structure. In any case it must be dry, otherwise the wood curves and the spaces between the boards appear. If we mount on the screed, the recommended relative humidity is up to 2%, and in the case of the wood structure, the recommended relative humidity is maximum 12%. Moreover, the substrate must be smooth and flat: flatness must not exceed 2mm / 1.5m linear deviation, clean: scratched or sanded, matured, without wax, grease, paint, oil, other debris and dust.
With regard to the installation,if the flooring is made of solid wood or laminated wood, it is appropriate to place it on an elastic layer and to join the wooden elements together with an adhesive inserted in the "nut" part of the "nut-feder" joint the adhesive comes out of the calculation if the joining system is click type). If the floor is of unfinished solid wood, we recommend that you adopt a fixed fitting by gluing with adhesive or on nailing glue. In this latter case, the assembly can be followed by various finishing work such as sanding, sanding, scraping (rarely) and dusting by suction and wiping. Upon your preference, the final operation is lacquering by applying 2-3 coats.
When selecting flooring compatible with underfloor heating, it is necessary to check:
1. Thermal resistance of the prosecutor's office and technical and economic aspects;
2. Dimensional stability.
The value of thermal resistance varies depending on the nature of the wood and, in particular, the thickness of the parquet. Taking into account only the low thickness of the parquet, without taking into account the negligible differences related to the essence of the wood, it is possible to establish two categories based on this size and the type of parquet:
a) masonry, industrial parquet, prefinished multilayer parquet: Thermal resistance R = 0,06 - 0,09 m²K / W, the equivalent of a 4mm carpet;
b) floating or massive parquet (14 mm prefabricated or 22 mm solid laminate): Thermal resistance R = 0.15 - 0.18 m²K / W, the equivalent of a 10mm carpet.
On the basis of this classification and depending on the thermal resistance, we can say that it is preferable (for energy saving purposes) to use a bonding flooring rather than floating or massive. For underfloor heating, the latter have lower performance than glued flooring, which has a lower thickness and better thermal conductivity.
From the category of laminate flooring, double-layer parquet with multilayer birch plywood flooring has the best qualities for underfloor heating because both its manufacturing technology and its small thickness ensure:
● Minimum thermal resistance that translates into energy saving;
● a stability to wood dilation / deformation.
This second aspect is very important. Indeed, the main effect of heating on solid wood elements is to reduce their humidity, thereby reducing the size and creating more or less important joints between the blades. The double layered parquet, thanks to its multilayer wood support, offers a maximum dimension of stability and greatly reduces the presence and size of these joints.
For low temperature heating installations (the maximum flow temperature inside the system is 40 ° - 45 ° C), the pipes must be embedded in a conglomerate capable of completely covering them and thus providing the best heat transmission. In most cases, these conglomerates are based on cement or anhydrite. Cement screed
It can be made of normal-purpose cement or quick-drying hydraulic substrates. In their execution, which is usually identical to traditional screeds, the surface has to be carefully treated and prepared so as to obtain a uniform, fine-grained superficial layer. An excessively smooth surface could cause slow drying and a poor socket of the parquet adhesive, while excessive roughness could cause problems of consistency and excessive glue.
After this is done (to be done by professionals) and before installing the flooring, superficial consolidation is imperative, by performing in the first step a sanding (with the monodisc for removal of the surface crumb layer) and, immediately afterwards, applying a reinforcing primer, of a chemical nature compatible with the adhesive used for bonding the flooring (follow the adhesive manufacturer's instructions). On this type of screed it is contraindicated the use of a primer or a water-based adhesive! From the first phases of the project, it will be taken into account that the pipes must
Coated with a screed of at least 30 mm thick, to allow good propagation of the heat and to avoid heat concentrations that could damage the flooring. Particular attention should be paid to the possibility of migration to the surface of any moisture contained in the layer (s) under the radiant panel (usually made up of high water retention materials). In order to diminish this negative influence, it is always recommended mounting, under the radiant panel, of a double layer of polyethylene as a vapor barrier. Before fully curing the screed, the joints must be prepareddilatation, cutting the screed in all places where they are needed, and which are usually:
at door thresholds;
In the center of large rooms (follow the manufacturer's and / or manufacturer's instructions Screed);
In the continuation (in section) of any technical joints present in the structure of the building.
It should be taken into account that the screed in general, and especially the underfloor heating, must be designed in such a way as to allow for the ideal characteristics of flatness, roughness, moisture, structural consistency and superficiality. When installing the flooring and other flooring on this type of support, it is preferable to avoid applying primers to correct any consistency problems or leveling products to restore flatness to the surface.
The artificial drying cycle of the screed
After at least 28 days from making it (time required by the manufacturer for quick-drying binders and anhydrides), the quick-drying cycle of the screed can be carried out by putting the heating system into operation and following the phases described below , so as to achieve the desired residual moisture percentage and release the strain withdrawal tensions, thereby permanently stabilizing it:
1. After disconnecting all ambient thermostatic probes, which would cause the heating system to operate only conditioned by the air temperature, start the plant by increasing the water temperature by 2-4 ° C per day until it reaches a maximum temperature of 40 - 45 ° C. Initially, the boiler must be operated at a starting temperature close to ambient temperature;
2. Maintain the system at maximum temperature for 1 or 2 weeks;
3. Shutting down the plant by lowering the temperature by about 5 ° C per day;
4. Leaving the system off for 5 to 10 days;
5. Restarting the boiler, progressively increasing the temperature;
6. Putting into operation a few days;
7. Progressively lowering the temperature and shutting down the boiler, waiting for the plant to cool down. At the end of this cycle, it will be necessary to check the residual moisture by using the calcium carbide method. The screed is dried when the moisture content is less than 1.7% CM for a cement screed and 0.2% CM for an anhydrous one.
Before locating the screed it is indispensable to locate and record the places where the sewers are located in order to be able to carry out the sampling without damaging the plant
To install double-layered parquet, a non-water-based adhesive (two- or two-component polyurethane or polyurethane epoxy-polyurethane) should be used and able to maintain the appropriate elasticity characteristics over time.
During installation, it is recommended that the expansion joints existing in the screed support be installed in the parquet. In their absence, it is recommended that at least the expansion joints of the parquet be achieved at the coincidence of the neighboring spaces (under the doors).
Typically, double layered parquet has exceptional dimensional stability, even in hostile conditions. Wood, by its nature, is subjected to dimensional variations that depend on humidity and ambient temperature. In order for this natural behavior not to cause undesirable effects on the floor, the ambient climate must always be maintained within the recommended limits:
The air temperature should be between 15 and 30 ° C and the relative air humidity (especially) should be maintained between 45% and 65%, this range of values corresponding, inter alia, to health and normal hygiene conditions for humans. In order to guarantee the stability of the flooring and especially the human physiological requirements, the temperature at the surface of the parquet should never exceed 26 - 27 ° C (it should be noted that modern, low-temperature installations provide notable ambient comfort at a floor temperature about 24-25 ° C). In order to avoid heat build-ups and, consequently, the appearance of joints or corrugated flooring, in addition to low thermal efficiency, it is advisable not to cover wood floors with thick carpets or other materials with high thermal resistance.
It should be borne in mind that prefabricated double-layered parquet, subjected to a particular and intense heating period, may have slight contractions and small joints between the blades but disappear once the heating system is switched off. If these phenomena occur, the particular construction features allow for optimal surface maintenance, since this type of parquet, although having a monolithic appearance, is actually composed of several blades, each of which forms a separate module, with the possibility of removing some of they do not produce superficial ruptures and, when the heating period ceases, with the possibility of approaching without showing perennial signs. For installations that also have cooling function, all anti-vapor and anti-condensation systems must be provided in order to avoid condensation formation at any level of the floor composition. The lack of these systems can make the flooring absorb moisture and, consequently, suffer dimensional deformations.