Choosing Screed for Underfloor Heating (UFH)
We would like to give you some tips on choosing screed for your underfloor heating, (UFH) whether a water (wet) or electric based system. Under floor heating is now the popular choice to use in domestic and commercial premises. Call us today for advice or a free quotation about your project.
Insulation should be laid beneath the UFH system to ensure that the heat always rises upwards.
We believe that traditional sand and cement screed is the ideal choice for underfloor heating. Manufacturers and suppliers generally recommend a minimum depth of 60mm to use with their systems, which is the standard depth for traditional screed. This depth works well with the flow of heat from the UFH system as it retains the heat for longer compared to thinner depths, making it more energy efficient.
Traditional screed is more economical especially on smaller sites then self leveling screeds which were created to cover vast areas. Anhydrite, (also known as liquid, poured, flow or self leveling) was created specifically to cover industrial spaces at speed and 2000 square metres a day can be poured. It is generally only on larger sites that anhydrite is more cost effective in comparison to traditional screed.
Screeding should take place as soon as possible after an underfloor heating zone is laid and pressure tested. The screeder must take care to protect the pipe work whilst working. By using a screed pump, the need to barrow is removed as the machine delivers the mixture via hoses whilst ensuring that the pipework is not damaged. The screeder must also ensure that the mixture is well compacted around the pipes to make certain that there are no voids or hollows.
The screeder must use a laser level to continually check that the floor is always level.
The floor should be allowed to cure and dry naturally until full strength is reached as per British Standards and manufacturers instructions. Generally 65mm will set within approx. 6-12 hrs if site mixed or 12-24 hrs if premixed and can then take light foot traffic. The full drying time of the floor will depend on the depth and products used.
Fast drying admixtures such as Isocrete K-screed/ Ronacrete Uniscreed/ Mapei Topchem or alternatives are added to the mixture and can be dry within 1-4 days depending on the make and depth, which allows for early laying of floor finishes.
Until the floor is fully cured and dried the heating system cannot be used.
Ceramic tiles bond well with traditional screed.
We operate as floor screeding contractors in the London, M25 and South East England. Click on the link below for further information on this subject:
