Under Floor Heating
The thermal resistance of wood differs with the species but is in the order of 0.13m2 K/W. Wood naturally reduces heat transfer through the whole floor construction and as a result wood flooring should only be considered over an under floor heating installation with full prior consultation with the heating engineer.
All of our engineered floors are suitable for installations with under floor heating systems. You must check with the manufacturer of the under floor heating system to ensure that the system can be properly controlled to ensure the maximum temperature at the surface of the timber floor will not exceed 27°c.
It is important that you set the under floor heating system to make sure that it cannot in any circumstance cause a floor surface temperature that exceeds 27ºc. The best way to do this is with an infrared heat monitor. Infrared monitors are usually inexpensive and will allow you to calibrate the maximum running temperature of your heating system to a floor surface temperature of 27*c.
For water systems this is easily achieved by adjusting the regulator to a maximum water temperature that is commensurate with a floor temperature of 27ºc.
For electric systems you will also need to set up the system so it is impossible for the floor temperature to exceed 27ºc.
Please note that the 27ºc is across the whole floor and it is common for poorly installed systems to have hot spots. The calibration of both water and electric systems needs to be measured against the hottest areas in the floor.
Please also note that under floor heating systems are designed to operate as a “slow” heating source. The appeal is that they omit an even level of heat over a long period of time. The only circumstances within most properly insulated homes that a temperature of 22ºc cannot be achieved with a floor temperature of 27ºc is when the 22ºc is demanded too quickly. In this respect if you use an under floor heating system like a conventional radiator, you will damage your floor as the short term temperature boast will cause excessive temperature in the floor
Please note that room temperature settings are NOT floor temperature settings. The temperature of the floor only needs to exceed 27ºc for a short period of time to damage your floor.
Early signs that your heating system is running too hot include:
Colour fade in the floors natural tone, small longitudinal splits along the centre and ends of a plank. (This normally prevalent around knots). If corrective action is not put in place quickly the hardwood layer in your floor will start to shrink. When this happens the hardwood layer will curl up at the edges.
In extreme circumstances the dried out hardwood layer will move to such a degree that it becomes loose and will start to delaminate from the backing layer. When dried out hardwood layers become loose they will normally need to be replaced, however in some circumstances the wear layer can be glued back into place. (The additional use of a micro nail gun will hold the boards in place whilst the glue dries). Replacing wear layers is a professional undertaking and requires the removal of either the entire plank from the floor or in some circumstances the removal of the hardwood wear layer. This can sometimes be undertaken without damaging the finish on the floor. However if the floor does not have bevels between each component, the floor will need to be refinished. The re-finish could be straight forward and only involve a light sand to the existing finish and then the application of additional coats of finish. Alternatively in some circumstances the floor will need sanding back to bare wood prior to re-finishing.
Please note that all Ted Todd engineered wood floors are tested for adhesive bond strength. The bond performance between the hardwood layer and core meets all European standards. Wood floors that fail over under floor heating fail due to shrinkage in the hardwood layer of the board and not due to poor adhesion.
Where possible we recommend that all floors are glued to the sub floor with Ted Todd MS Flex adhesive but this will depend on the system and sub floor you have chosen. Please ensure the sub floor is rated to allow direct gluing of timber floors.
The ambient humidity and temperature should all ways be maintained.
Do not lay rugs or large items that can trap the heat over floors with under floor heating systems as this can cause excessive drying of the timber.
Some electric under floor heating systems are not suitable for installations with timber flooring, check with the manufacturer that the system will adhere to the above criteria.
Water Fed Systems
Your under floor heating installer must make sure that all services running underneath the floor have been fully tested before the laying starts.
Once the screed is dry, follow heat up procedure as follows:
- Day 1 20°C
- Day 2 30°C
- Day 3 40°C
- Day 4 50°C (or the maximum planned operating temperature and maintained constantly for 7 days)
- Day 12 40°C
- Day 13 30°C
- Day 14 30°C
- Day 15 Switch off heating system
Please allow 4 days before a final moisture reading is taken.
If more than 7 days pass between the last cooling down day and the start of laying the flooring, the under floor heating system should be run at minimum operating temperature for 2 days. The system should then be switched off for at least 4 days before a further moisture check is carried out prior to laying.
Some electric under floor heating systems are not suitable for installations with timber flooring, check with the manufacturer that the system will adhere to the general guidelines.
Heating Systems Over Suspended Floors
For installations where the under floor heating is suspended in joists or an overlay system, consult your supplier of the heating system to ensure it is rated for use with engineered wood floors and follow their installation instructions.