1930's house black "tar" under parquet flooring

[Tigercubrider]

Finger parquet
https://www.lumberjackshop.co.uk/solid-wood-flooring/european-oak-mosaics

 

[Deleted member 174758]

... the flooring guy, explained that once they start using their machines to sand parquet flooring, the weight of the machine is likely to disturb other loose staves. His advice was to rip the whole lot up and start from fresh. Apparently, the cost of removing the tar like substance is prohibitive. My understanding is that they use very different floor sanders to those used by people who sand softwood floor boards (ie. not drum sanders).

My experience is maybe a bit different as it's all been on listed buildings. What you seem to find is wear (hollows) in the vicinity of door ways and areas with loose blocks (BTW, technically a stave is a long narrow plank like you see in a kitchen worktop, a bowling alley or a barrel), sometimes areas with mechanical damage where furniture, etc has been dragged across the floor, occasional burn marks (from coal fires) and some loose areas. So the bad areas get dug out and replaced then the whole lot gets sanded (ideally with a random orbit sander). I haven't seen one so bad that it all had to get dug up, yet and I can just imagine trying to get that past the Conservation Officer