Finishes - Installing flagstones on a Limecrete floor

Flagstones are one of the oldest floor finishes used for traditional buildings, they are characterised by a large footprint and varying thicknesses from 40mm to above 150mm. Flagstones are mostly used when lifting and relaying the existing floor finish in a refurbishment / renovation project or when materials are sourced from reclamation yards (most new stone tiles are thinner and of consistent thickness – See Installing stone or quarry tiles on a Limecrete floor

Due to the size and weight of flagstones, they can be bedded on a mix of Lime and course sand / aggregate similar to that used for the Limecrete, the depth of bed will vary across the floor based on the thickness of the flagstones. When determining the floor level, the thickest flagstone should be selected and allowance made for a 15-20mm bed of mortar, this will determine the height of the slab and then all of the other flagstones will need varying depths of bedding material to ensure they are level.

Example Mix: 2.5 parts course aggregate to 1 part NHL 3.5 (NHL 5 can be used if left over from laying the Limecrete)