After completion, both types of shelters were either capped over with earth or the playground re-tarmaced over. Both types also had toilet compartments at either end of the galleries with crude spring doors for privacy being stencilled 'Ladies' and 'Gents'. The 'Square' type shelter often had large steel reinforcing girders set within it to strengthen the construction. The 'Arch' type features galleries painted throughout with whitewash, while the 'Square' type has a natural concrete finish throughout with whitewash only being applied near the entrance areas, possibly to ease ingress and egress in blackout conditions. Local correspondence has revealed that the sections for the square type were brought up from Cornwall, being made at the Pentewan concrete block works, near Par, the sand coming from the nearby silted up harbour.
Many shelters feature one or two internal drains.
Primary source research tends to point to two uses. Both types have one or more escape hatches. The function of these hatches was to provide emergency escape from the shelter in the event of the main entrance and entrance stairwell being blocked by the rubble of a direct hit on a close-by large building. These hatches are vertically overhead and set in the roof of both types of shelter. Each hatch was reached and opened by means of a steel ladder, and was provided with a ventilation grill to provide fresh air to the shelter.