Case Studies

Long Curtain Moat

Client – Portsmouth City Council

Value – £9,500

Duration – 2 weeks

Type – Sea Defence


Suttle Projects were contracted to carry out the repairs that were required to repoint the open joints and replace and secure the missing stone blockwork, in various locations, along the 35m long vertical seawall at Long Curtain Moat, in Old Portsmouth.

Prior to repointing the joints with a M60 mortar mix, each one was cleaned. This involved clearing areas of algae and, by utilising a hand-breaker, removing the loose and unsound material.

The repointing works along the lower sections of the seawall were tidally constrained.  Thus, the works were carried out either side of low tide.  Operatives were supplied with life jackets and a life buoy, and efforts to clear the working area began comfortably before the end of each shift. This ensured that there was adequate time to safely vacate the area.

The stone blockwork was held in a compound by Portsmouth City Council which was transported to the site by a 5T mini-excavator.  Blocks were cut to the correct size on site.

In replacing the stone blockwork, it was necessary to install a scaffold.  This was set up with a double guard rail to ensure the operative’s safety whilst working at height.  The operative on the scaffold placed the mortar and dowel bars prior to the blockwork being lifted into position by the mini-excavator, avoiding the need for manual handling.

The weather and sea conditions were monitored at all times to ensure that the exposed areas of the seawall were protected from possible damage.

Although the seawall is not a designated scheduled monument, the structures either side of the wall are.  Therefore, care was required to ensure that these were not damaged during the construction period.  Care was also taken to ensure that none of the works impacted negatively on the surrounding environment.  Biodegradable hydraulic oil was used in the machinery and, where required, the removal of algae was done by eco-friendly pressure washing.

The beach area and promenade remained open to the public throughout the works and Suttle Projects were required to take appropriate precautions to protect the public.