Wooden Flooring in conjunction with Under Floor Heating

Conditions and procedures to be followed when installing an Engineered Wooden Floor with underfloor heating  

The following procedures must be used when installing and using engineered wooden flooring products in combination with an Under Floor Heating system (UFH). 

Installing an engineered wooden floor with an UFH system can be very beneficial and will ensure your home is as comfortable as possible. 

When laying an engineered wooden floor in combination with UFH you must follow a number of specific rules to keep your wooden floor in good condition for a lifetime. 

Wood is a living natural material, it will "move'' (shrink and swell) under changing climatic conditions. Taking this into consideration it is vital that the heating process of the UFH system is carried out properly in order to prevent stresses being created within the wood flooring. 

Ensure that the moisture content of the wood is between 7% to 9% (wood flooring is generally 7%) and that the relative humidity in your living area is at the appropriate level which is between 35% to 60% during the entire year to avoid problems with shrinkage and swelling please follow these rules. 

The thickness of the concrete floor screed or anhydrite floor that is applied over the heating pipes must be at least 30mm.

 The heating protocol must be followed regardless of the season, to achieve the allowed moisture percentage of the screed. The screed must be at least 28 days old before the underfloor heating is started up. Set the water temperature to 20 degrees Celsius on the first day. 

The water temperature in the pipes must be subsequently increased by a maximum of 5 degrees Celsius every 24 hours. You are allowed to do this up to 45 degrees Celsius. This maximum temperature must be maintained for a few days. It is important to know what the thickness is in mm of the screed to be able to calculate the exact the number of days to dry out the screed at the appropriate level. For example if the screed is 50 mm thick you will need to maintain the maximum temperature for 5 days. The number of days is in relation to the thickness in mm that your screed floor is thick.

 The reduction of the water temperature must be done in the reverse order. The total procedure will take up to approximately 14 days. During this procedure ensure that there is good ventilation in all the rooms so that any moisture that will be released can be correctly discharged.   

The moisture percentage of the concrete screed must not be higher than 1.8 % before the wooden floor is laid, for an anhydrite floor the moisture percentage must be not higher than 0.3 %. 

Switch off the heating system two days before the engineered wooden floor is to be laid. The room temperature should be not lower than 18 degrees Celsius and the relative Air humidity should be between 35% to 60 % 

The wooden floor must be allowed to acclimatize for at least 48 hours in it’s packaging in the room where it is to be installed. 

We recommend that our engineered wooden floors are glued down with Bona R850 adhesive which has been designed for underfloor heating and that it is done professionally to ensure that there are no air gaps which can be a barrier to heat transfer. 

When the wooden floor has been installed the floor heating system can be put into operation in accordance with the following protocol. This must  only be done 48 hours after the floor has been installed:  

• The first day the water temperature in the pipes should be set at 10 degrees Celsius, after that the water temperature can be increased by a maximum of 5 degrees Celsius every 24 hours. The temperature of the water in the pipes must not be higher than 40 degrees Celsius and the wooden floor temperature must be not higher than 25 degrees Celsius to avoid “dry-out” or ''stress'' problems in your wooden floor. 
• The procedure must be followed in the reverse order when the system is switched off. We recommend that you set the thermostat during the heating period at the same level for the entire day to avoid big temperature fluctuations.  

The normal conditions for human habitation and wooden floors in the living rooms should be as follows:Room temperature should be around 20 degrees Celsius.

• Relative humidity in the living room should be between 35% to 60%
• The maximum temperature of the wooden floor should never be more than 25 degrees Celsius to avoid excessive drying-out problems, which can cause stresses in the wooden floor. 
• To control the relative humidity during the heating period a Humidifier system can be used to keep it above 35% in the living rooms.
• Beech and Maple are not normally recommended for underfloor heating systems.