Joints in parquet are nothing out of the ordinary and usually there is neither inferior material quality nor poorly executed laying work behind them. Nevertheless, parquet joints are often perceived as annoying. In the following article you can read why parquet joints are not bad in themselves and what you can use to fill joints in your parquet .
Recommended products for closing joints in hardwood flooring:
What creates joints in the parquet?
The main cause of joints in the parquet is the natural swelling and shrinkage behaviour of the natural floor covering. Wood is a natural product that has hygroscopic properties.
This means, it binds water vapour from the air and releases it again, which changes both the wood moisture and the volume of the material depending on the room climate.
This behavior is called swelling and shrinkage – or colloquially formulated: The wood works.
The optimal conditions for parquet are at a room temperature of 20 to 22°C and a relative humidity of 55 to 60%.
In this indoor climate, professionally laid parquet hardly works and therefore has no joints.
Even if the annual average values are maintained, it is still inevitable that they will be exceeded in summer and undercut in winter. Because parquet always adapts to the ambient climate. The bonding of parquet with parquet adhesive can help a little. This somewhat reduces the swelling and shrinkage behaviour.
Especially during the heating period, the air in heated rooms becomes drier, the moisture in the wood decreases, the parquet disappears and joints are created.
How pronounced these can be depends, among other things, on the type of laying: floating parquet works more strongly than glued parquet because the parquet panels only lie loosely on top of each other, whereas with full-surface gluing they are firmly connected to the subfloor.
However, the type of wood and the type of parquet also play a role: parquet made of beech or maple tends to have a higher swelling and shrinking behaviour than, for example, oak.
Are joints in the parquet a deficiency?
In general, joints in the parquet are quite their purpose in view of the inevitable source and shrinkage of the wood.
They give the parquet the necessary room for expansion without damaging the floor. However, a distinction must be made between intended and unintended joints.
By intentional joints are to be understood those joints, which were deliberately placed in order to achieve an optimal result in the laying of the parquet.
For example, when laying parquet in the edge areas or wherever the floor is applied to immovable elements such as doors, stair connections, heating pipes or heavy furniture, appropriate expansion joints must be taken into account in order to compensate for tensions of the parquet .
However, if joints occur between the individual parquet elements, these are often not wanted.
Nevertheless, these can hardly be completely avoided – especially with solid parquet there will always be fugue formation.
Accordingly, joints with a width of between 0.1 and 0.5 mm (for parquet on underfloor heating systems up to 0.8 mm) are considered perfectly normal.
If the joint width is between 0.5 and 1 mm, this can be considered a conspicuity, joints over 1 mm are ultimately outside the tolerance range.
However, it is always necessary to take into account the circumstances in which the joints occurred.
In most cases, a expert is consulted in these cases, who clarifies in an expert opinion whether the exceeding of the tolerance limit was caused by the laying work or by other influencing factors, such as lack of measures to control or regulate the air humidity or incorrect heating and ventilation behaviour.
The dimensional tolerances are regulated in the standards ATV DIN 18356 Parquet work and DIN 18202 Tolerances in building construction.
Should parquet joints be filled?
While expansion joints in the edge areas usually disappear behind skirting boards, joints remain visible on the surface of the parquet.
Older parquet, in particular, often has relatively large joints, which is due on the one hand to the previously usual laying distances and on the other hand to the factor time.
However, even relatively newly laid parquet can, for the reasons mentioned above, lead to more joints, especially in winter.
These can not only negatively affect the appearance of the parquet, but sometimes develop into dirt traps that are difficult to clean or – with the appropriate width – to annoying stumbling blocks.
It is therefore perfectly sensible to repair and fill parquet joints. If there are only small dents or scratches in the parquet, these can be repaired with a parquet repair set and melting wax.
Which parquet joint fillers are available?
For filling joints in the parquet floor, there are basically different options that are used depending on the joint width to be able to.
Fugue kitt for parquet
For narrow joints, fugue kit is a proven option. This can also be easily made from wood glue and sawdust itself by mixing both components into a tough mass.
The paste is then applied to the joints with a spatula and, after complete drying, sanded down with a sanding machine or sandpaper and resealed.
It is optimal if the joints are repaired within the scope of the parquet renovation.
The grinding dust caused by the grinding process is excellently suited for the production of joint putty and also has the same colour as the parquet.
Alternatively, special joint fillers in different colours can be purchased from specialist retailers. For example, joints can also be deliberately filled in a contrasting colour to give the parquet a new look.
As joint filler is relatively liquid, it is in principle only recommended for joints up to a maximum width of 5 mm, as it can otherwise run out of the joints.
Acrylic-based joint fillers
If wider joints are to be repaired, special acrylic-based joint fillers are the better choice. These are also available in different colour variants and remain permanently elastic even after filling the joints.
This preserves the necessary flexibility so that the parquet can continue to work.
In principle, these properties also apply to silicone. Acrylic joint fillers are still preferred.
This is because, in contrast to silicone joint sealing compound, acrylic joint sealing compound can also be sanded down and painted or oiled without any problems. Due to its brittle consistency, hard or melting wax is also recommended only for removing defects in hardwood flooring and not for filling joints.
In order to achieve an optimal result of the acrylic joint fillers, the joints should first be carefully cleaned.
In doing so, any remaining joint fillings must be removed completely and the joint must be made dust-free with a parquet vacuum cleaner.
In order to work cleanly, it is recommended to glue the edges of the joints with painter’s crepe. This gives the joints an exact closure and avoids unnecessary contamination of the parquet.
For the application of the joint filler, a cartridge press is best used, with which the joint mass is inserted into the joint up to about 1 – 2 mm via plank level, according to the manufacturer’s recommendations.
If the joint filler is dry, this supernade can be cut off or sanded and the joint sealed. Care must be taken to ensure that the products used are compatible with the joint mass.
Filling joints with wooden strips
Regardless of the composition, joint fillers generally have a limited service life of around 10 years.
After that, the joints should be refilled. However, if you want to fill joints for longer, you can also repair them with wooden strips. However, this method involves significantly more work.
In the first step, the joints must be brought to the same width with a knife or planer. Afterwards, the cut and adapted wooden strips with wood glue and wooden hammer are inserted into the joint. Any supernatry is then sanded and the surface sealed.