The use of limecrete is desirable in a historic building as it allows naturally occurring moisture to escape through the floor. The use of modern cement floors has caused some problems as moisture is unable to escape through the floor and is pushed towards the walls and can cause damp patches to occur in or around the base of the wall.
Glapor recycled foam glass insulation may be used in conjunction with a limecrete slab for insulating values. Glapor Foam Glass Aggregate is an insulation material for underground use. Recycled foam glass aggregate saves energy and also contributes to a comfortable indoor environment.
Glapor is a high quality foamed glass gravel made from 100% recycled glass. It is a versatile material; lightweight, load bearing and thermally insulating, making it an excellent material for a variety of ground based applications.
Glapor comes as an aggregate which allows it to be installed incredibly quickly. It is permanently stable, has a strong resistance to insects and rodents and has excellent compressive strength.
A base of clean hardcore (minimum depth 150mm) may be used. It should be well compacted down by use of a vibrating plate. A limecrete floor requires no D.P.M. (damp proof membrane) as the lime method is to allow moisture to breathe through a structure.
Limecrete is laid in layers of normally no more than 50 mm. Greater thicknesses are achieved by adding subsequent layers to build up the desired thickness.
Limecrete should be mixed to the consistency of a floor screed i.e., a semi-dry state, which will hold together when squeezed by hand, wet traditional concrete type mixes will result in excessive shrinkage. If possible a screed mixer or roller pan mill should be used and drum cement mixers tend to result in the mix balling.
The limecrete can be finished by tamping with a wooden or steel tamper and the surface can be rubbed up using either a timber or polyurethane float.
Limecrete floors are fully compatible with under floor heating. When covering the water pipes then a 75mm layer of limecrete is necessary. It is essential that when the under floor heating is commissioned the amount of heat directed to the pipes within the limecrete is very gradually increased to minimise shrinkage.
Once laid limecrete should be kept damp for 96 hours (minimum). This may call for spraying with water during warm and hot periods. Limecrete must always be protected from freezing conditions for the first 10 days after laying. Traffic should be avoided for 10 days, and thereafter protective boards should cover the work for 3 weeks before exposure to general traffic.
When selecting a floor covering it is important to select a material that continues the ability of the floor to breath such as natural stone or terracotta tiles. Timber floors are also an option but it is best to lay the wooden boards on treated timber battens to allow a air gap and to incorporate vents to allow a degree of air exchange.
A point to keep in mind when installing a limecrete floor is that it should not be used to support masonry walls or chimneys. Suitable foundations need to be planned and put in place before the limecrete floor is laid. Lighter timber stud walls may be acceptable.
Explore the Roundtower limecrete floor system.