PPS 6 Planning Archaeology and the Built Heritage·Page 27·6.13
Listing Grade and Sensitivity to Alteration
Listing grade alone is not a reliable indicator of a building's sensitivity to alteration. Grade B buildings listed as unaltered examples of vernacular types are equally at risk of having their special interest damaged by inappropriate changes as higher grades.
The listing grade of a building is not of itself a reliable indicator of it's sensitivity to alteration or extension. Many Grade B buildings may have been specifically listed because they are relatively unaltered examples of a once common vernacular building type. Accordingly they can as readily have their special interest ruined by an inappropriate alteration or extension as can Grade A or B+ structures.
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