Underfloor Heating Concrete

Concrete and Screed products are natural conductors of heat and therefore ideal products to be used in conjunction with underfloor heating.

Higher thermal transfer of heat, this is achieved because the concrete encases the underfloor heating pipes and therefore more surface area of the pipe is in contact with the concrete.

The concrete must be a minimum of 75mm in depth and reinforced with steel mesh, the concrete can be installed at 150mm in depth with the underfloor heating suspended between two layers of steel mesh approximately 1/3 of the way up from the bottom of the concrete.

In deep floors the underfloor heating will be less responsive, however underfloor heating systems are designed to hold the temperature of a specific zone at the desired temperature, so the only time the system heats up from cold is during the commissioning of the system, after that the heating is generally varying around 3 to 4 degrees if set back timers are being used to allow room temperatures to drop lower whilst rooms are not in use.  The bigger challenge with underfloor heating in deeper concretes is cool down times because the concrete is acting as a storage heater. 

For example: If the underfloor heating is installed in a 150mm concrete slab in a heavily glazed area and the room stat is

set at 21 degrees during the spring and summer there is a risk that the system will call for heat at 3am to bring the room up to Temperature and then at 6am the sun rises and warms the room through the glazing, the mass of heat stored in the floor can cause the room to over heat, therefore we recommend that room temperatures are reduced by 2 or 3 degrees during the warmer months in heavily glazed areas, when installed in deeper polished concrete floors.

Apart from the benefit of the thermal store 150mm polished concrete floors require less contraction joints, normally at

around 6m centres depending on the aspect ratio of the room.

Section drawings of underfloor heating in concrete are below.

We design and supply under floor heating systems our systems can be viewed at https://www.underfloorheatingsupply.co.uk

Commissioning of under floor heating in concrete can be done after 28 days

When commissioning the system switch on the heating system to run at a flow temperature of 25°C, or the minimum allowable by the system, and leave for three days 

Increase the flow temperature in 5°C increments per day up to a maximum of 55°C. Leave at this temperature for a minimum of 3 days

Reduce the flow temperature by 5°C per day down to 25°C before switching off and allowing to cool.

Midland Flooring can supply and install the insulation, underfloor heating concrete and polished concrete.