Traditional Building Renovation, Restoration & Conservation
Natural & Healthy
Contemporary & Historic
Limecrete
Limecrete is a mixture of natural hydraulic lime (NHL) and aggregate that can be used to create breathable floors. It offers
increased vapour permeability which is especially important for traditional buildings, and is often used in combination with
breathable membranes. LECA (lightweight expanded clay aggregate) can be used instead of sand to create a warmer floor
design. The LECA can be used both as a loose fill insulation under the limecrete slab and incorporated into the limecrete
slab by mixing with NHLs.
Shepton Mallet, Somerset
We were asked to install a lightweight, breathable flooring system as an alternative to an impermeable concrete slab to help with the free-flow of moisture through this floor. This is particularly important in houses that have either earth floors or no damp proof course. In these cases it is rarely advisable to install tanking as this doesn’t alleviate the moisture issue, but rather moves it around the base of the wall, and could cause structural decay.
The earth floor was first levelled and compacted and a new drainage system was installed sub-floor.Then the first geo-textile barrier was laid and the the loosefill LECA was deposited and lightly compacted. We asked the family to put together a ‘time capsule’ that could be buried within this layer; they jumped at the chance of placing some modern personal items, alongside various antique finds that had come from the excavation.
The next geo-textile layer was then laid and the LECA/hydraulic lime mortar was mixed, poured and levelled onto this. After the slab had set, the tubing for the underfloor heating system was installed.
The final limecrete screed was then mixed and levelled on top of the tubing sealing it all together.
Once the slab has set a limestone tile floor will be laid.