Key Benefits of Underfloor Heating Screed
There are several advantages to using underfloor heating, including uniform room temperature, increased conductivity, faster room heating and cooling, improved comfort, safety, and space efficiency. Underfloor heating is particularly well-suited for use with various energy production systems, especially renewable, low temperature systems like air and ground source heat pumps.
When combined with low temperature underfloor heating, flowing thermal screeds provide maximum comfort and energy savings.
Improved energy efficiency:
Underfloor heating screed, especially liquid/self-levelling types, has higher thermal conductivity for faster heat transfer and lower running costs.
Thinner profile and versatility:
Liquid/self-levelling screed can be installed at just 45–50mm, compared to 65mm for traditional screed, allowing more design flexibility.
Faster installation and drying:
Liquid/self-levelling screed has a quicker installation process and dries faster than traditional sand and cement screed.
Liquid Floor Screed Compatibility
Overall, the compatibility of the underfloor heating screed is crucial for the effective and long-term performance of the entire underfloor heating system. Careful planning, selection of the right screed type, and proper installation techniques are key to ensuring compatibility.
Proper installation and integration:
The screed must be installed in a way that fully encapsulates the underfloor heating pipes or cables, with no air pockets that could reduce heat transfer.
Screed type and thickness:
Liquid/self-levelling screeds are generally more compatible, as they can be installed at a thinner 45–50mm depth compared to 65mm for traditional sand and cement screed. The thinner profile improves heat transfer.
Expansion and curing:
Expansion joints and perimeter foam are needed to allow for material expansion and contraction.
Post installation up to 48 hours Gypsol screed, having been installed into a suitably sealed building envelope, should be protected from ingress of water and extremes of temperature. External windows and door openings should remain closed in order to allow the screed to set. The screed may be trafficked by light foot traffic after 24 to 48 hours from installation. Gypsol screed is self curing and therefore does not require a curing membrane. The finished screed should not be excessively heated during this period, although keeping the environment at or around 20°C is beneficial. Significant air movement across the screed should be avoided in order to reduce the risk of plastic shrinkage cracking.
After 48 hours the Gypsol screed is ready to begin drying. It is of significant benefit at this stage to provide as much ventilation as is reasonably practicable, whilst maintaining protection for the screed from ingress of external water. Windows and doors can remain open for as long as possible, assuming conditions allow, during the working day. This will help to provide good air exchange to remove moisture from the air above the screed, and allow the residual moisture to escape. After 72 hours dehumidifiers may be introduced to assist the drying process if desired. Between 72 hours and 7 days any loose or friable surface laitance may be removed by lightly sanding with a rotary floor sander and a medium grit sanding disc or other suitable means of removal. Foot traffic can continue during this period.
After 7 days The Gypsol screed can now be loaded and the work area returned to full service. Underfloor heating can be commissioned and run and unlike cement based screeds which cannot be heated for 28 days or force dried at all, Gypsol screeds can be force dried either using the underfloor heating, or using space heaters and fans. In either case it is important to remove the moisture from the air above the screed either by ventilation, extraction or dehumidification in order to allow the screed to dry properly. This assists greatly with early preparation for floor coverings. If space heaters are used these should not be of the fossil fuel variety e.g. gas burners as the burning of gas emits moisture back into the air reducing the benefit of heating significantly. Electrical or forced air movement heaters are suitable. Protection during the remainder of the construction period should continue in order to protect the Gypsol screed from re-wetting which could delay the drying period. It is not however desirable that the screed should be covered with impervious sheeting during construction.
Prior to floor covering installation In accordance with the relevant national standards for floor coverings the surface of the screed should be inspected and should satisfy the following:
- It should be clean and free from chemicals likely to interfere with adhesion
- It should be sound, hard and free from fractures other than planned joints
- It should be free from loose friable laitance, dust, construction debris and loose surface contamination e.g. mud, building adhesive and bricklaying mortar
- It should be suitably dry or an approved method of moisture management such as a damp proof membrane or uncoupling technology employed (see additional notes)
- Any underfloor heating must have been commissioned and run.
