Historic solid floor care and underfloor heating

SPAB (The Society for the Protection of Ancient buildings has recently published a guidance note.

http://www.spab.org.uk/downloads/Historic%20Floors%20Guidance%20Note.pdf

This guidance reinforces Historic England's advice about the need to think carefully about strategies for the repair and maintenance of historic solid floors. Wear, patination, cracking and undulations are significant elements of the character of such floors and once they have been lifted, their historic character cannot properly be recreated. Traditional construction methods for tiled or flag floors rely on moisture's being able to evaporate through the lime mortar joints so as to prevent the build up of moisture below the floor. Re-bedding and re-pointing in Portland cement mortar prevents this from occurring.

Medieval encaustic tiles, Winchester Cathedral

Installing underfloor heating is a popular solution in solid floored buildings but this disturbs the original floor and, if laid on a modern concrete slab with a damp proof membrane, dampness in the earth beneath the floor is likely to be displaced to a higher level in the surrounding walls by capillary action. 'Breathable' sub-floors can be constructed but they need careful specification and the SPAB guide provides advice on this and alternative methods such as trench heating, if the specific circumstances justify an invasive excavation.