Easy Screed can be poured from 10mm to 50mm. When used as a topping over underfloor heating the minimum depth we can pour is 35mm over standard 16mm underfloor heating pipe. There are many pipe sizes and ways to install the pipe, including clipping directly onto insulation or installation of a track to clip the pipes into. Our requirement is that there should be 20mm of Easy Screed over the highest point of the underfloor heating pipe. For example, if you are using a 16mm pipe, clipped onto a high density insulation then 35mm of Easy Screed is sufficient. If your plumber chooses to install the pipes using a 25mm track, then a 45mm screed will be required. Remember, the thinner the screed the better for reducing the lead-time to get your heat into the rooms.