1. FULL RENOVATION OF FINISHED WOODEN FLOOR
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Finishing a wooden floor is not an assembly line job. Each floor is unique when it comes to appearance, condition, type of wood, etc. Each environment in which a floor is situated is also unique in respect to wear and the effects of everyday chemicals. Temperature and humidity are other factors that can vary a great deal from one job to another. The choice of products and handling of the products must vary according to the situation. The following advice can be seen as a guide for success in using water-based finishes.
To enhance the colouring of exotic woods and
reduce the discolouring of water-based finishes, especially on Russian ash, it is recommended that you use Synteko Exotic Wood Sealer (EWS).
1. FULL RENOVATION OF FINISHED WOODEN FLOORS
Suitable products
Sealers: SEALER, SEALMASTER
Finishes: BASIC, PRO, TOP, TOP 5, BEST, STAR
Before beginning, the floor must be checked to see that its condition permits re-sanding. If it is of laminated (engineered) parquet, ensure that the wear layer is still well-glued to the underlying layer. Tap with your fingernail in a few locations and listen for indications that the wear layer is no longer firmly secured to the sub-layer. If it is not, you can be certain that the wear layer will buckle because of the stress changes involved in sanding and finishing. In the wood is a living material, humidity shifts cause the wood to move. Solid board flooring is often dried too quickly and far too little. If such a floor is installed and is immediately sanded and finished, the risk of substantial contraction crevices is very high.
Occasionally, the finish can function as glue in the tongues and grooves, and the risk of major cracks upon contraction is large. This phenomenon is known as side-bonding or panalising.
In these cases, where the final results are less than what the consumer expected, it is important to inform the consumer that the condition of the wood floor construction can jeopardise the final results.
NOTE: TARKETT DIAMANTFURU, BJÖRK DIAMANT, BRUNBOK, BOK MAHOGNY, KÄHRS DONAUEK AND JUNKERS HOMOGENEOUS WOODEN FLOORING MAY NOT BE FINISHED WITH WATERBORNE FLOOR FINISHES.
SANDING
A good base is a fundamental requirement for a good surface finish. This is an old truth that still applies, especially when working with waterborne floor finishes. Keep machines in good order and use high-quality sandpaper. Rough sanding is performed with coarse paper and high roller pressure. It is important to sand so that the floor is levelled as much as possible. Floor finishes are developed to flow easily, and if the floor is uneven, the finish will be thicker in depressions. If there are deep impressions where spot sanding is necessary, the sanded areas should be smoothed to the sides as much as possible. Never omit more than one coarseness grade while sanding. The norm is 50 and up.
Fine 120-grit paper should be used in finish sanding and with the least possible roller pressure. If the roller pressure is too high during finish sanding, soft spring wood will compress. If moisture from the lacquer later begins to affect the wood, the spring wood will swell back to its original volume, which results in noticeable heightening.
During finish sanding, it is also important that the sandpaper be of good quality and not excessively worn. The abrasive material should cut off the wood fibres without pressing them down into the wood. This is very important in keeping grain raise to a minimum.
BEFORE FINISHING
Vacuuming prior to finishing is very important. Be sure to also remove dust from skirting, heating units, window recesses and similar objects and areas.
All finishes should be shaken before use. Do this before vacuuming so that air mixed into the finish during shaking has a few minutes to escape before use. The finish should be at room temperature when applied. If the finish is too cold, it flows much less freely and also releases air poorly, which can result in brush stroke marks and air bubbles remaining after drying. It takes about seven hours to warm the lacquer from 0°C to 20°C. This period can be hastened by placing the lacquer container in a bathtub and rinsing with water at 40°C. Never use hot water alone: hot water can cause clumps to form in the finish.
If possible, there should be good ventilation when the initial coat is applied. This permits the lacquer to dry faster, which naturally saves time, but also results in less grain raise. On sunny summer days, direct sunlight should be blocked if possible. The finish sets very quickly if the floor is warm and the risk of visible overlaps and bubble formation increases significantly.
START FINISHING
All waterborne finishes contain small amounts of basic amines that chiefly affect oak. It is therefore important to apply the finish in an even coat. If drying conditions are poor (high relative humidity because of the weather or because the room has recently been wallpapered, for example), you must apply the finish somewhat more thinly to avoid discolouration.
Synteko's water-based finishes are single-component, with the exception of Synteko Best.
With Synteko Best, the hardener 1648 should be added shortly before finishing. Be careful to add the correct amount.
Affix the strainer and lid, and shake the container immediately for at least 15 seconds.
If the hardener is syrupy (high viscosity), it will not mix properly and must not be used.
Be careful when handling the hardener: all hardener are reactive substances that even react to skin. If you should get hardener on your hands, immediately wash them with soap and warm water. Ensure that the finish is not stored at temperatures above room temperature. This can lead to the formation of clumps in the finish.
FIRST COAT - APPLICATION WITH APPLICATOR OR ROLLER
If you prefer to work with an applicator or roller when applying the first coat, it is very important that the application is even. An uneven first coat will result in uneven colour tones, especially on oak.
Do not permit finish pools to remain on the floor. If the finish is poured directly from the container, it must be quickly spread before the wood absorbs too much moisture. If possible, apply the finish parallel to the shortest wall of the room (from one long wall to the other). Overlap times will thus be as brief as possible. Work gently with the tool so that no finish drops splash across the floor. Should this occur, the drops must be removed before the next coat is applied. One litre of finish should suffice for between 8m² and 20 m², depending on the absorbency of the wood type.
The golden rule is to give the wood what it can absorb. You thus attain the best foundation for the next coat, and at the same time, the drying time is optimised. Be sure to apply enough finish to achieve even wetting of the wood. A wet finish darkens the wood, but afterwards as the finish dries, the wood lightens again. Wait until the wood has an even colour tone before performing intermediate sanding. If the finish coat is thicker in some places, it takes longer for the water in the finish to evaporate and the surface appears spotty because of colour differences. If the next coat is applied too early, it will take a long time before the floor achieves an even colour tone.
FIRST COAT - APPLICATION WITH SPATULA
Applying the initial coat with a spatula has become more common in working with water-based floor finishes. There are several advantages over brushes or rollers: it is easier to apply a finish evenly with a spatula; the drying time is much shorter; and grain raise is minimal. Intermediate sanding is often unnecessary and vacuuming between applications is thus avoided. This method works best if the finish has a thick consistency.
The spatula should have a stainless steel blade and be sufficiently pliable that it can follow the contours of the shallow depressions on the floor. Using a spatula, one litre will cover between 20m² and 30 m², which means that the finish must be applied three times to attain the same thickness as achieved with a brush or roller application.
The first two applications are made wet-on-wet for optimal evenness. Thereafter, wait approximately 15 minutes until the surface has an even colour tone before the next application. It is important that the spatula be kept sharp so that it functions as a scraping iron and cut the grain raise. This is necessary for achieving good results without intermediate sanding.
BEFORE FINAL FINISHING
If the initial coat was applied with an applicator or roller, the floor should first be sanded with 150-grade sandpaper. If an oscillating sander is used, it should be used in quick passes, back and forth and with the least possible pressure so that the sandpaper does not become clogged, which would otherwise result in ineffective sanding. If a buffer is used the buffer should be moved faster the heavier the buffer is to avoid clogging the paper or screen.
After the surface has been sanded, it should be carefully vacuumed. If the initial coat has been applied with an spatula, check to see if intermediate sanding is necessary.
Before final finishing, ventilation should be checked to ensure that there is no draft over the finish surface during final finishing. Bear in mind that if a door to a stairwell is open, there will often be a draft over the floor even far into the flat. In cases where powerful mechanical ventilation systems are presenting use, such as in sport halls, these should be turned off. After finishing the application the ventilation may be turned on depending on how the finish dries. Large areas must be completed within app. 2 hours. In large areas an applicator-based application is preferred.
FINAL FINISHING - TOP COATS
Final finishing provides body for the surface and forms a wear layer that will withstand years of wear and tear. Final finishing is therefore more abundant than the initial coat. Under normal conditions, 8-10m² per litre is appropriate. If the floor is uneven along the walls, for example, it is important to apply the finish a little more thinly in these locations so that the finish does not flow into depressions and form an excessively thick layer. If humidity is high, you must also apply the finish more thinly so that it does not remain wet too long. If the finish remains wet for too long. If it does, discolouration may occur, especially on oak. There are also risks of flow problems and renewed grain raise. In the worst case scenario curing can also be affected resulting in a soft surface.
Just as with the initial coat, final finishing should be performed so that application is parallel to the shortest wall to permit overlaps to be made as quickly as possible. With larger surfaces, an application edge can sometimes begin to set before the overlap is made. If this occurs, the edge will be visible after drying. To avoid this, periodically return to the application edge and make an overlapping pass to keep the edge wet. Pour the finish off to the side and pick up a little with each stroke.
If you are using a roller, the finish should first be roughly distributed over a surface of about 2 m². The finish is then evened out by rolling at a right angle to the first rolling. Use rollers with an app. 8 mm pile.
Mohair rollers transport more air to the lacquer when rolled in one direction than the other. You should therefore roll in the direction that produces the fewest air bubbles.
Close to walls and corners, and other areas that are difficult to access, a smaller brush must be used.
When the finish application is complete, never fully close all doors. While there should not be a draft across the finish surface, normal ventilation in the area is favourable for the drying process.
NOTE: IN THE DAYS IMMEDIATELY FOLLOWING FINISHING, THE SURFACE MUST NOT BE COVERED WITH ANY MATERIAL THAT DOES NOT ALLOW EVAPORATION.
NOTE: NEVER APPLY TAPE TO THE FINISHED SURFACE.