Design - Can it be used externally?

We do not recommend the use of Sublime® floor externally, due to the nature of the limecrete binder it is more moisture open than a concrete slab making it more susceptible to holding moisture and therefore suffering from freeze-thaw damage.

The benefits of a fully breathable floor system are of most use internally when trying to protect an existing building, a lot of the properties that make the system a good choice internally, are not applicable externally. The Glapor foamed glass provides damp protection to keep moisture out of the building and insulation to keep heat in, these are not of benefit externally where the slab is subjected to the weather from above and there is no heat to retain. While the Glapor would provide a free draining structural base to lay a slab on it does not add any performance benefits that a standard sub-base would not.

The limecrete is softer and more susceptible to damage than a concrete slab would be whilst also having a longer curing time and greater requirements for protection from weather as it cures. There is no benefit of using a limecrete slab over a concrete slab externally, there are a range of lower carbon or cement free binders available if the environmental cost of the materials are of concern.