General Information
Floating Floor underfloor heating systems, have been designed to be incorporated into a floor construction that consist of sheets of flooring insulation that has a structural floor board floated straight over the top with no additional fixing to the insulation. These systems have very similar properties to the suspended and batten floor constructions types, and will operate in exactly the same way once they are installed.
Floating floor underfloor heating can be one of the quickest to install. Because you do not have to wait for screeds to harden and there is no need for additional battens or joists to be fitted, the installation time is reduced dramatically. If you have a project where speed is of the essence, then a floating floor may be the best option.
Floating floors are designed to overlay on an existing floor, and consist of a routed sheet of insulation with grooves set at pre determined spacings which give the system its specific heat output. Once the routed boards have been laid according to our design plans, a heat transfer clip is pushed into the grooves within the insulation. When all the clips are in place, the pipe can be installed into these clips. All of the clips and pipe will finish flush within the thickness of the insulation.
When the pipe work has been installed into the insulation and you are ready for the floor deck to go down, lay the aluminium conducting plates across the top of insulation and pipe work. This plate connects all of the heat transfer clips and draws the heat away from the pipe work dispersing it across the floor to provide an even floor temperature. The final stage, before the floor deck is fixed down, is to lay a lightweight polythene sheet across the top of the aluminium plate; this is refered to as a vapour barrier.
Before the pipe work is covered with the flooring and aluminium sheets, you have to fill the system with water and pressure test it. This test will determine that no damage has occurred to the pipe during its installation and can be monitored during the floor laying process to check for damage, should it occur.
Insulation
The insulation depth can vary for different projects. Building regulations will require a specific amount of insulation to be used. This will ususallybe more than the underfloor heating system requires, and therefore not be a problem. In most situations the grooved sheets of insulation are made from 50mm polystyrene, and depending on your building regulation requirements may need to be substituted with additional insulation to bring it up to the values specified.
Floating floors will usually use rigid insulation boards such as polystyrene or a PIR board, if additional insulation is required beneath the grooved polystyrene, then you should avoid materials like Rockwool or fibreglass due to their compressive nature. Always check with building regulations and insulation suppliers for specific requirements regarding your project.
Build Up Heights
Floating floors can increase the floor height, this increase is usually dependant on the amount of insulation that is used. The build height for floating floors can be relatively low compared to solid floors, but if building regulations specify additional insulation below the grooved boards, then this can increase the build height significantly. If for example, you use 50mm PIR insulation in addition to the supplied 50mm grooved insulation, then you would be looking at a total of 100mm of insulation. Robbens can supply the grooved insulation boards, between 35 and 70mm in thickness with the optimum board thickness being 50mm. You will need in addition to the grooved insulation a structural floor deck to go over the top, so please always allow for this additional depth.
Temperatures and outputs
Floating floors have a limited output compared to the screed systems, although this output should be more than enough heat for modern well insulated buildings. Although their outputs are lower, the water temperature required to run them is higher, normally around 55 – 60c. These specifications will allow the system to produce 70w/m2 with a maximum surface temperature of 27c.
In a modern building with high levels of insulation and modern high specification double glazing, the floor temperatures are usually within a few degrees of the air temperature in the room and will provide a warm and comfortable atmosphere even during very cold weather.
If you have a poorly insulated building with little or no insulation, draughty single glazed windows and open flues, you will find that the system will have to work considerably hard to achieve a comfortable room temperatures in cold weather. We recommend you refer to the heat loss calculations that are prepared at the quotation stage to ensure that these issues are highlighted as early on in the project as possible.
