Under-floor heating demystified. Natural movements due to EMC, humidity and temperature. Do acclimatisation. A warm feeling.
The impact of changing humidity and temperatures on wooden floors can be very significant.
Installing a wooden floor above under-floor heating has long been perceived as complicated and troublesome but in fact under-floor heating reduces the natural differences throughout the year by providing a constant temperature and therefore an ideal environment for our natural product.
Taking simple precautions ensures the best possible results:
• completing all wet jobs before commencing the installation of a wooden floor;
• ensuring sub-floor is sufficiently dry before the installation commences;
• avoiding moisture from underneath by using damp proof membranes, possibly together with primers or
vapour barriers;
• allowing sufficient acclimatisation of the floor before installation;
• providing necessary expansion gaps for the floor;
• taking precautions preventing extreme humidity by using (de)humidifiers;
• staying within comfortable room temperatures;
• only gradually increasing / decreasing the temperature between the floor and the sub-floor, if above
under-floor heating.
It is very important to state that problems are usually due to outside factors. Failure to comply with moisture content recommendations and site condition requirements can result in excessive shrinkage or expansion of the boards, cupping or concave floor boards or even walls being dislocated! Therefore always use a professional, authorised installer.
Remember: Your wooden floor simply tries to stay in balance with its surroundings. Give it space and make yourself comfortable!
Properly acclimatised wood floors are not automatically suitable for use above under-floor heating!
Engineered flooring is much more stable, due to its construction, than solid floors. And for solid floors, only certain species should be used and unstable species, such as Beech, should not be used at all.
Width is important. Any gaps will be more visible in wider boards as both shrinkage and expansion are a percentage of the width. We therefore recommend that only engineered flooring up to 155 mm be used above under-floor heating and for the solid floors, only wood which has been specially heat-treated.
This does not mean that our collection of wider engineered flooring (up to 190 mm wide), nor the other solid flooring (up to 130 mm wide), cannot be laid with very good results above under-floor heating. However, more movement must be expected, prepared for and accepted.
Important Points:
• The sub-floor must be sufficiently dry. For a generic sand and cement screed, this means MC of max. 3%. Once the screed is dried naturally, the under-floor heating is to be turned on and gradually increased until the maximum loading is reached. To assist drying and to achieve uniformity of temperature within the screed it is helpful, during this phase, to cover the screed with a light coating of sawdust. Maximum loading is to be maintained for at least 7 days, same time adequate ventilation is performed to ensure that the released humidity can escape.
• All under-floor services (not only heating services) beneath the floor to be tested fully before laying starts.
• It is essential that hot water or steam pipes, other than those for floor warming purpose, are lagged or otherwise insulated in order to reduce movement of the flooring in that area. They must also be fixed at a sufficient depth to avoid ...
ENVIRONMENT
