Floor installing technology

When you buy a thick parquet board (fabricated thick wood board for flooring), you need to understand that unless this board is properly installed, you will never realize all the advantages of this floor covering. Specialists can be entrusted with this job, or you can do it yourself on condition you do the job according to all the necessary regulations.

Irrespective of the bearing structure of the facility, you will discover very impressive possibilities as far as the design is concerned, not only due to the variety of colors and the texture of wood, but also due to various combinations of the sizes of floor board and the type of installing it:

All the chosen materials must go through the so called "acclimatization" for at least three days. The moisture content of the applied materials must be in the range of 6% - 10%, it should not exceed 12%.

Floor installing is done in a few stages and can be fulfilled in different technologies:

• Installing over cement floor
• Furring strips over screed finished concrete
• Plywood underlayment over screed finished concrete
• Installing over bearing wooden structures
• Installing over the existing wooden floor
• Assembling a thick parquet board (thick wood block floor)
• Dressing and application of a protective-decorative coat

Floor is the final stage of all the repair -construction work in the room, house, building, etc. When you are ready to install your floor, you need to make sure that the premises in question are ready for that: all the doors and windows have been installed, the walls and the concrete are leveled (a tolerant deviation should not exceed 2mm over each 2m), that everything is dry (moisture content should not exceed 12%), a relative air humidity is 40-60%, only then you can get to the floor.. We need to say here that to achieve all these necessary conditions for the future work takes at least two months after all the other work is finished.

If you do not have special devices to measure the moisture content of the screed finished concrete, we can suggest simple methods of determining its condition:

1. Take a list of polyethylene film, 1m x 1m in size, and scotch it to the concrete. Give it 24 hours and remove the film: if you see a wet stain on the concrete, it is not dry, you need to put off the installation of the floor for some time.

2. There is another simple method of determining - with the help of a small rubber rug. Place the rubber rug on the screed finished concrete and press the rug to it with a concrete or brick block. Again give it 24 hours and remove the rug. If the concrete under the rug got darker, that means that the tested screed finished concrete is not ready for the future work. Here we need to say that this method works better on a light concrete, a darker concrete conceals the moisture much better.

Only when you make sure that the screed finished concrete is ready, you can begin the first part of the work - establishing an underlayment for floor covering. But first of all you need to build a moisture barrier which separates structurally different materials - concrete and wood.

We recommend to use special bitumen compounds or a film of foamed polyethylene about 2mm thick. The compounds are spread on the surface with a special roller, you can add a solvent, while doing that, to achieve the consistency necessary for this work. The film is spread with some overlapping, or the sheets should touch.

At present there is a great number of materials that can be used for this purpose. The choice of the material depends on personal preferences or on the price. Taking these two factors -price/quality - into consideration, we would recommend a film 2-3mm thick of foamed polyethylene. It is spread on the surface with an overlapping of 5-7cm.

Establishing an underlayment for floor covering can be done in two ways:

This technology uses for the underlayment the so called "laggi" -wooden strips (furring strips) of rectangular cross section. We recommend to use dressed strips with the cross section of 50-55 x 70-100mm. Their moisture content should not exceed 12%.

The laggi are tightly fastened to the concrete with the help of screws and wooden dowels every 50cm and in the direction perpendicular to the direction of the future floor covering, the screw should penetrate into the dowel in the concrete 3-4mm under the surface. The axis distance between any two laggis must be 25-30cm.

An alternative way of fastening the laggis can be gluing them with a bituminous sealant. Here we need to say, though, that this technology requires using as a moisture barrier the bitumen compounds compatible to the applied glue composition, and it is rightly justified for fear of damaging the communication lines hidden in the screed.

Before the floor boards are installed, it is necessary to level them first, sanding the parts that are higher than the general level, or - the other way around -placing pieces of wood in the places that are lower than the general level. The maximal deviation from the leveled surface should not exceed 2mm over every 2m.

To make the slabs between the floors more soundproof and to eliminate heat losses (first floors with no basements), we recommend to fill the gap between the laggi with an insulant.

Right before you start installing the floor, a moisture protecting film needs to be laid and bolt-stapled over the laggi, only then you can get to assembling the floor itself.

This technology uses a water-resistant plywood not less than 18mm thick for the underlayment. The standard sheets of plywood (1500x1500 or 1220x2440mm) need to be cut along the smallest side into strips 40-60cm wide.

The installation of plywood should be done diagonally towards the direction of the future covering, leaving a space of 2-3mm between the sheets and 10mm between the edges of the sheets and the walls. The plywood sheets are tightly fastened to the concrete with the help of screws and wooden dowels either 15 screws and dowels per 1sq.m. or 9 screws and dowels per sheet, the screw should penetrate into the dowel in the concrete 3-4mm under the surface.

An alternative way of fastening the laggis can be gluing them with a bituminous sealant. Here we need to say, though, that this technology requires using as a moisture barrier the bitumen compounds compatible to the applied glue composition, and also using plywood sheets two or three times a smaller cutting size in length.

We recommend to use special bitumen compounds or a film of foamed polyethylene about 2mm thick. The mastic is spread on the surface with a special roller, you can add a solvent, while doing that, to achieve the consistency necessary for this work. The film is spread with some overlapping, or the sheets should touch.

Before you install the board, you need to do a rough sanding of the plywood underlayment with a belt-sander using an abrasive strip of the 40-60 grit, and when the underlayment is finally very smooth, take all the dust off it.

This technology is meant for premises with wooden floors and that's why any of the below materials can be used for the underlayment:

• Plywood not less than 12mm thick,
• Osp board not less than 18mm thick,
• Planking underlayment not less than 20mm thick

We need to say here that the given thicknesses work only if the axis differences between the laggis are 30-40 cm. Practically in life these numbers differ a great deal. In such cases we recommend to reinforce the existing bearing system in the same (or cross out ) directions to bring it closer to the necessary numbers.

Before the underlayment is installed, it is necessary to level the laggis first. The maximal deviation from the leveled surface should not exceed 2mm over every 2m.

Sheet materials (plywood and OSP) are fastened to the laggis over the waterproof film with the help of screws not less than 5 screws per every linear meter or 9 screws per sheet, the screw should penetrate into the dowel in the sheet 3-4mm under the surface. The installation of the sheet material needs to be done in the direction of the future covering, leaving a space of 2-3mm between the sheets and 10mm between the edges of the sheets and the walls. Very important that the edges of the sheets touch on the laggis, not in between them.

If you do a planking underlayment, it is necessary to observe its direction - it should be diagonal to the direction of the future covering.

Before you install a thick board, you need to do a rough sanding of the planking or sheet underlayment with a belt-sander using an abrasive strip of the 40-60 grit, and when the underlayment is finally very smooth, take all the dust off it.

It was very often the case when the house was being built, they installed a traditional "40mm" or a "50mm" which was not dry. With the time the board got dry and possibly was reinstalled, but it still does not meet the requirements or the ideas of the owners about a fabulously -looking, practical and long-living covering.

Before you install a floor board over the existing wooden floor, you need to make sure that the wooden floor is fit for the job, that it is capable of bearing pretty big loads. If this is the case, we do not recommend you to take the risk, but first to remove the old floor and possibly the underlayment, and then reinstall them according to the pattern that is good for your premises. If the existing floor looks good, begin to start doing the underlayment for the future new covering.

For this you first need to do a rough sanding of the old floor with a belt-sander using an abrasive strip of the 40-60 grit, and when the underlayment is finally very smooth, take all the dust off it.

If you are not sure that there exists a moisture barrier under the old floor, we recommend to install it on the already sanded old floor before you install a new one. Besides, if you install a new floor over the old wooden floor, it is necessary to observe the direction of installing: it is not recommended to install the new floor in the same direction as the old floor; the best are the diagonal or cross out directions.

Though installing in the same direction with the existing floor is also possible. In order to do this it is necessary to cover the already sanded existing floor with sheets of plywood not less than 12mm thick, and do the rough sanding of the plywood underlayment.

The fastening of the board to the underlayment is done with the help of self-tapping screws ( size 3x35-45mm) with the spacing of 20-30cm. First of all you need to drill the board at the side where the tongue is at the angle of 50 degrees. In case the board is installed on the flat underlayment (not over a moisture barrier), we recommend to use a parquet glue, which is laid on the underlayment with a spattle strictly over the square of the installed board.

Important: do not try to install the board only on the glue, it is necessary to regular fasten it with self-tapping screws. The glue contributes to the installation, no doubt, but it is not strictly necessary while assembling the new floor.

While assembling, make sure the boards touch in the cross out and longitudinal directions, draw them tightly together with wedges if necessary. Do not forget to leave a space of 7-10mm between the walls and the floor covering along the perimeter.

Make sure that you assemble the first row in such a way that the groove faces the wall, and fastening with the self-tapping screws is done through the face surface, but you need to bear in mind that they need to be hidden under the moldings, when the latter are installed.

The last row is also fastened with self-tapping screws through the face surface. If you install a floor board more than 150mm wide, you need an additional fastening through the face surface. Usually, if you want your floor to look antique or rustic, the face self-tapping screws should penetrate into the dowels 9-10mm below the surface, then they are covered with a plug of the same wood species.

Sanding does not mean that every board should be ideally smooth, this could be done easier and cheaper in the production facility, but first of all sanding is meant to eliminate all the mistakes during assembling; ideally the surface must be absolutely smooth.

When you get to this stage of the work, inspect most attentively all the places where the self-tapping screws were drilled through the face surface. If the screws do not properly penetrate the dowels, they are a definite threat for the sanding materials and sanders. We recommend to use belt and disc sanders in most of the areas, and in the difficult areas - corners and wall edges use smaller hand or special corner sanders.

Use the abrasive strip with the grit of 60, 80,100 and 120. The finishing sanding should be done by a disc sander using abrasive discs of 120 or- 150 grit. Here it is important to say that when you use the sanders successively, you should not jump over more than one typosize of granularity, this may lead to a poor quality of the sanded surface.

The sanding is considered to be of high quality if (on condition you have observed all the necessary regulations), the total pick up of wood from the floor surface is not more than 1mm. In this case the surface could be considered ideal.

After you are done with the sanding, you need to install the first layer immediately. First of all the covering will not only lend the wood a more beautiful look, but also will protect it from moisture and mechanical damage. Second, installing the floor covering directly on the wood structure opened by the sanding, but it will provide for a better adhesion by a deeper penetration of the covering into the pores.

Important: when you buy a finish covering, make sure that you know the technology of its installation and that the applied materials are compatible. Also make sure that they are good for the wood species in question.

Before you install a protective-decorative coat, or a toning composition (if you have decided to change the natural color of the wood), make sure that all the dust is taken from the premises. To achieve the best results when applying the varnishes, do an intermediate sanding between the layers by a disc sander. When all this has been done, install the floor moldings which give the floor a finished look.