Breathable, insulated and limecrete floors have now become quite common in the UK but one design does not fit all buildings and this is one in a series of case studies which may help you decide on the best floor build up for your old building. It has long been recognised that in old buildings we should avoid pushing dampness in to walls from the ground by not using un draining compacted fill, cement subbases and impermeable layers and membranes. By allowing the lowest section of the floor build up, the sub base, to drain freely and by insulating within and above this sub base it is possible to create well insulated, free draining floors, that help prevent dampness rising up walls in old buildings. This case study illustrates one such build up.