Limecrete Floors

The fundamental issue facing the owners of older properties is how to bring them up to modern standards with regard to heating, insulation, airtightness and freedom from damp. Increasingly, they also need to be energy efficient, satisfying the ever-growing demand for carbon reduction while retaining their distinctive character. Limecrete floors help solve these problems. Read more

Section image of a limecrete floor

Today's Building Regulations require the solid floors of most buildings to have high levels of insulation and high compressive strength as well as impermeable barriers to prevent moisture migrating through the floor into the buildings fabric. The Building Regulations are absolute for new dwellings and are the goal for existing traditional buildings, but the regulations can be a little more flexible for old buildings if there are good reasons not to conform.

Where a new floor slab is to be created, the best option is to use a slab/screed based on lime which is breathable rather than cement, which is virtually impermeable. A limecrete floor can be designed to meet modern insulation requirements and can incorporate under floor heating.

Preventing ground water penetration requires some form of capillary break, this can be achieved using an impermeable damp-proof membrane (DPM) and would usually include petro-chemical based insulation. An arguably much better approach is to use recycled foam glass aggregate as the insulated sub-base. Being made from recycled glass, it's more environmentally friendly than an insulation based on petro-chemicals. Furthermore, due mainly to the open pore structure of the foam glass, it's non-capillary and won't draw any moisture from the sub-soil.

The installation is very straightforward, an example specification would be as below:

  • Floor finish
  • 100mm lime screed (2.5:1 by volume, sharp sand:NHL5)
  • Underfloor heating (UFH) if required embedded within screed
  • Geogrid for attaching UFH pipes if required
  • Geotextile membrane
  • 200mm compacted foam glass
  • Firm sub-soil

Based on a floor area of 50m² with an exposed perimeter of 28.5m = U value 0.25 W/(m²K)

It can be complicated working out volumes and U-values. So just tell us what you need and we will work it out for you. For example, we can calculate all the design information you need for your floor: thickness, insulation values using our accredited design programme, along with full material quotes including delivery.

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