limecrete mixing and application

Limecrete is the term used to describe the entire floor composite. All our Limecrete floors are mixed by gauging and set on site, taking great care, especially when working with the lime.

We tend to favour the use of NHL5 lime as the binder with LECA as this produces a light weight aggregate that is both breathable and strong.

limecrete section

Even in the worst of conditions the limecrete will be set for foot traffic within 48hrs and ready for final finish within 5 days.

limecrete with underfloor heating

Another of the many advantage of limecrete is its user friendliness when it comes to underfloor heating. Once the limecrete has set, it is an easy task to clip in under floor heating pipes and to then install the screed and final floor finish.

laying tiles over limecrete

Limecrete is a relatively recent innovation in building terms but fulfils a long overdue need when installing solid floors in historic properties; breathability.

The conventional wisdom in the building industry over the past 50 years has been to install concrete floors over a dpc. If this was done correctly then it is likely the damp never came back but, as is so often the case, poor workmanship and/or poor specification can create a whole host of problems. We have come across several cases where the dpc was omitted or was not contiguous to the outside walls and where the underlying moisture had found its way to the edge of the slab and up the walls. The use of limecrete has effectively eradicated this problem as the entire surface area of the slab is able to breathe.

At the Organic Building Company we have developed our own techniques to good effect. Depending on the depth of the oversite and the desire for improved insulation, the composite will typically consist of at least 50mm of LECA, a breather membrane, 100-150mm Lime/LECA and then 60-75 mm of Lime screed followed by the final finish, set on a bed of lime mortar.

Depending on the depths of the various layers limecrete floors can be specified to conform to Part L (Insulation Standards) of the Building Regulations, which are applicable to new buildings but the same standard can also be adopted for historical properties, resulting in a warm floor.

Click here to download this fact sheet in pdf form.