Tiling Onto A Lime-Based Floor
There are generally two reasons why customers choose to lay a lime-based floor: the desire for a more ecologically-sound alternative to concrete, or the need for a breathable floor due to damp issues common to the age and structure of the building. Lime inclusive construction mixes have been used for centuries across the world, with Limecrete the modern interpretation of this traditional building material.
What Is Limecrete?
Limecrete, a combination of natural hydraulic lime (NHL) and lightweight aggregate, is seen as a ‘green’ building product as its manufacturing carbon footprint is lower than producing concrete. Limecrete enables vapour to escape, reducing damp and mould issues, and therefore is often prescribed for listed buildings for restoration authenticity and practical reasons. With high flexural strength, Limecrete copes with absorbing natural movement in both old and new buildings and this flexibility, coupled high thermal mass, makes Limecrete ideal for use with under floor heating (UHF).
Which Tiles To Use
When breathability is an installation concern, the best tiling option is natural limestone floor tiles as they absorb, disperse, and enable damp to evaporate. With a naturally higher porosity than denser marble stone tiles, limestone floor tiles are widely available with a tumbled antiqued edge, often the preferred choice for listed properties, period cottages, and barn conversions.
When fixing natural stone tiles to a lime base, the use of a bonding agent such as Kerakoll Primer A, is key to ensuring the adhesive can perform to its optimum. Under no circumstances should PVR be used as a bonding agent or primer.
With natural stone tiles on a lime base, we recommend a high specification, breathable, white, rapid setting, flexible adhesive, such as Kerakoll H40 Marmorex. Formulated with powdered Carrara marble (instead of sand like basic adhesives), Kerakoll H40 Marmorex is the very best adhesive available and was formulated specifically for use with natural stone tiles, which are susceptible to staining and marking with more basic adhesives. The crushed Carrara marble micro-balls, makes workability second to none, and having a long bucket life means you won’t waste adhesive whilst you leave the room to cut a tile.
Gaps between natural stone tiles laid on a lime base, should be larger the normal minimum of 3mm, between 5-8mm will allow aid the evaporation of damp.