FAQ – Parquet questions and answers
This FAQs provide a brief overview.
Room and building climate
What room climate is recommended for parquet floors? Wood is a hygroscopic material; it absorbs or looses water in relation to the surrounding environment. Wood will expand and contract (swell and shrink) with fluctuating changes in Relative Humidity and Air Temperature until it reaches its equilibrium moisture content level (emc). This results in swelling and shrinking within the floor, which can lead to shrinkage gaps or cupping. This process is described as the wood ‘working’. In principle, this should not be viewed as something negative, so much as a natural characteristic of the natural material wood. To minimize the unavoidable changes in dimensions as far as possible, we recommend that you maintain a room climate of 20°C Air Temperature and a Relative Humidity Level of 40 to 60% throughout the year. All our timber used for floors is dried to within ± 2% of its equilibrium moisture content (emc) value, ie the level it is expected to achieve in service. The wood moisture content of the timber floor at the time of delivery is calculated to a level of Relative Humidity of 40. It is also helpful if you select a timber species with a low swelling and shrinking (expansion and contraction) characteristics and a timber species with a low speed of absorption of moisture (eg. Oak). It is especially important to maintain the right room climate in the cold/winter months, as micro gaps/gaps will form if the timber is allowed to dry out due to the air being excessively dry. In this case, using an air humidifier at the beginning of the cold/winter months can assist in maintaining relative humidity levels. We therefore recommend that you avoid airing your home for extended periods during the winter. At the beginning and during the cold/winter months, we recommend you install air humidifiers, house plants etc; all sources of moisture; this will help prevent your parquet floor from “shrinking” excessively and causing micro gaps/gaps.
In general, it is important to remember that installing a wooden floor in a damp room (eg. a bathroom) will mean increased work and maintenance expense. You will need to be more careful with regards to water-splashing out of baths, showers, etc., as well as expansion and cupping. As far as possible to minimize the unavoidable changes in the dimensions of the timber, we recommend that you maintain a room climate of 20°C Air Temperature and a Relative Humidity level of 60% throughout the year. It is also helpful if you select a timber species with low expansion and contraction characteristics, and a timber with a low speed of absorption of moisture (eg: oak). Ideally, we would recommend products with a multi-layered structure (2 or 3 layers). It is also advisable to lay one or two rows of tiles or stone immediately next to the bath/shower or basin to allow for any spray/splashes. We do not recommend timber floors to be installed in wet rooms. Every time you use the bathroom, you should wipe away as much spray/splashed/pooled water as soon as possible to prevent the timber being exposed to water (risk of staining and cupping). The bathroom must be ventilated regularly. Every time you fill the bath or take a shower, ensure that the room is thoroughly ventilated to regulate the room climate. Maintenance should be carried out as and when necessary, depending on how much the bathroom is used. This may involve renewal of the impregnating layer which should be carried out if the water no longer “pools” on the surface and begins to penetrate into the surface instead. Water stains and changes in dimensions due to fluctuations in wood moisture content can be prevented by regular maintenance and inspection.
What should I be careful of when installing parquet in low-energy and passive homes, and in buildings with controlled ventilation of the living spaces in general?
Due to the fact that buildings clad in air-tight shells often feature air exchange rates that are too high, room climates can often become extremely dry during the cold months. If this is the case, please pay particular attention to our recommendations regarding climate, and the ideal setting of a controlled system for ventilating your living space, with regards to air exchange rates. An ideal room climate of 20°C Air Temperature and a Relative Humidity level of 40 to 60% is our recommendation. Please bear in mind you will save valuable heating energy by doing so, a lower room temperature feels more pleasant when air humidity is high. At the beginning, and during the cold/winter months, we recommend you install air humidifiers, house plants, etc; all sources of moisture; this will help prevent your parquet floor from shrinking excessively and causing microgaps / gaps. To monitor relative air humidity, we recommend that you install a hygrometer in the house.
Colour variations are also a typical characteristic of the natural material timber, which can vary from tree to tree, and also depend on the area/region where it has been grown. For this reason, colour variations can appear between different production batches and also within a single production batch. This is also true of coloured surfaces, as the amount of colour pigments absorbed can create different colour tones due to the variation in cell structure of the natural product wood.
‘Fuming’ creates the dark colouring of parquet wood (predominantly oak), while still retaining the natural colour variation and graining of the wood. It involves a reaction of substances within the wood, and imitates a natural process. This natural process normally takes place when oak trees have been stored for long periods of time in swamps and bogs, where they are cut off from air, and due to a chemical reaction, the wood takes on a uniform, intensely dark colouring – commonly known as “bog oak”. As a result of the “fuming process” the wood takes on this new colouring throughout its cross-section, which is why it is referred to as ‘core-fuming’. One of the benefits of core-fuming is that when the parquet floor is renovated/sanded, the colour character of the wood is retained even if it’s sanded down several times. Due to fluctuating levels of tannin in oak, the fuming produces naturally diverse colour and structure in the parquet. As with all timber species, even core-fumed oak can change colour with the passing of time. While the process of core-fuming may limit such variations in colour, the wood can still yellow and lighten, depending on the duration and intensity of the exposure to sunlight.
After the floor has been installed, exposure to sunlight can cause changes in the colour of the wood, depending on the intensity of the light and of various substances within the wood. Different wood species react differently to light in terms of the strength, speed and nature of these changes (yellowing, darkening or bleaching).
In principle, the same specifications and approvals apply for all our products as those for hot water/“wet” underfloor heating. In an underfloor heating system providing heat by means of electrical heating wires, you should take more care to ensure the surface temperature does not exceed 29°C. The floor heating up too quickly or malfunctioning can cause increased surface temperatures and consequently floor failure. This also applies to “carbon film” type electric underfloor heating. In this case, too, we recommend a room climate of 20° C Air Temperature and a Relative Humidity level between 40 – 60%. You should be particularly careful when trying to remove a timber floor from this type of underfloor heating. Please contact a specialist in underfloor heating for precise technical requirements.
Maintaining the correct wood moisture content (emc) is crucial to minimize general changes in the dimensions of the floor and the formation of micro gaps/gaps (particularly during the cold/winter months). Weitzer Parkett recommends a room climate of 40% Air temperature and a Relative Humidity Level of 60%. The surface temperature of the parquet floor must not exceed 29°C. You should also avoid airing your home for extended periods during the winter, as this leads to a reduction in air humidity. At the beginning and during the cold/winter months, we recommend you install air humidifiers, house plants etc; all sources of moisture; this will help prevent your parquet floor from „shrinking“ excessively and causing micro gaps/gaps. Where rugs are used during the cold months, you should expect micro gaps/gaps to form in these areas (heat accumulation). In the summer months, unnecessary sources of moisture should be avoided. To monitor relative air humidity, we recommend that you place a hygrometer in the house.
Floating installation of parquet with underfloor heating is only suitable up to a point, as this type of installation technique will increase the overall thermal resistance. The combination of the thermal resistance of the underlay and unavoidable air gap due to the level of the subfloor (eg. unevenness in screed etc.) Weitzer Parkett recommends products to be fully adhered by a specialist installation firm.
Plain/clean grades with a significant proportion of visible annual rings (exquisite/nature, for example) help to reduce swelling and shrinkage, and are therefore recommended for installation on underfloor heating.
In principle, any of the parquet types supplied by Weitzer Parkett can be installed on top of underfloor heating. As far as suitability is concerned, it is not the structure of the multi-layer parquet products that is crucial so much as the wood species (see Point 6). Your Weitzer Parkett partner will be happy to offer you advice in this case.
For decades now, parquet has been tried-and-tested to the satisfaction of customers when installed on top of hot water/wet underfloor heating. The specialist under-floor heating installer plays an important role, and should guarantee correct advice and proper installation. The prerequisite is that the heating system should always be installed by experts, and the screed used is installed to the relevant standards. Always ensure the under floor heating has been “commissioned” properly prior to installing a timber floor.