I notice that the issue of whether to rehabilitate the Spa sea wall in Scarborough as it stands or to dump masses of rock ballast in front of it still exercises Scarborough Borough Council on occasions.
I carried out a cursory survey of the wall for the Sons of Neptune in 2011 and concluded that, beyond requiring minor repairs to the fronting masonry and pointing (ie what should be normal maintenance), it appeared to be sound.
A recent survey has discovered – by poking a rod through occasional sites where pointing has been eroded - that there may be voids behind the masonry here and there. The application of conventional ground-penetrating radar would enable those observations to be checked and quantified as it has been on sea walls elsewhere.
Should such voids indeed prove to be present they could easily be remedied economically by injecting super-consolidating resins.
I assume Scarborough Borough Council is aware of these techniques but, if not, I am sure that the Sons of Neptune would be pleased to advise it.
Dr Bruce Denness
Isle of Wight