Broadbent Building, Heron Hall Academy

Heron Hall Academy

The Broadbent Building and adjacent gym block on the site of the former Middlesex University campus in Enfield, has undergone a major refurbishment as part of the new Heron Hall Academy project.

The art-deco facade is of a special interest and incorporates, now listed ceramic tiles. The building is constructed from brick with reinforced concrete floor slabs supported by reinforced concrete columns and beams.

Working as a specialist sub-contractor to Willmott Dixon Construction, following successful completion of other recent projects, we have been repairing and coating the external concrete elements which include the window cills, window heads and roof overhang, which project around the full perimeter of the buildings on all facades, as well as the entrance canopies.

The works have been carried out using Flexcrete materials and have included; Monolote hand-placed repair mortar for the repairs the the defective concrete and Monolevel 250F as a fairing coat, which has been specially formulated for application over existing coatings, being applied to all exposed concrete surfaces. To complete the system two coats of Monodex Smooth, a protective anti-carbonation coating primed with Bond-Prime, was applied. The system provided the client with 15 year guarantee.

Whilst on site we were also instructed to carry out internal concrete repairs using Flexcrete Monomix repair mortar, external brick stitching using Helifix Helibars and the installation of new expansion joints.

We are due to return to site in the new year to compete the second phase of the works.

Worth Abbey

The Abbey Church at Worth in West Sussex was built in 1966 and consecrated for worship in 1974. It is has the largest capacity of any church in Sussex seating up to 900 people and the monks gather 6 times daily to pray.

The grade II* listed church was designed by the Architect Frances Pollen and is constructed from insitu concrete with a felt roof. To achieve the large open space he used a bridge building technique never before used in a church.  It is considered by many to be the finest example of 1960s modernist architecture in Britain.

Kier were awarded the year long refurbishment contract and we secured the subcontract to restore both the internal and external concrete.

Whilst our works were carried out, other trades completed lowering of the floor to the choir area, upgrading lighting and sound systems, alterations to M & E, re-roofing and window replacement.

External repairs were carried out to all reinforced concrete, with preparation by dry ice blasting to remove old coatings from the ribbed surfaces and high-pressure water jetting to prepare uncoated smooth surfaces. The prepared concrete was treated using a migrating corrosion inhibitor, followed by the application of a pigmented, elastomeric coating. All products were manufactured by Sika Ltd.

Internally, the reinforced concrete ribs which support the roof above, together with the two chapel areas, were prepared and treated using a micro-porous pigmented coating, providing a uniform finish to otherwise patchy surfaces. Products for this element of the works were manufactured by Keim Mineral Paints Ltd.

The refurbishment of the church was successfully completed in time for reopening on Pentecost Sunday as planned.

The Arnussi

The Arnussi

Built in 1923, The Arnussi is a homage to Egyptian & Middle-Eastern architecture.

Upon returning to England from the Sinai Desert in Egypt after the First World War, original owner Percy Stammwitz built his home in Sunbury-on-Thames, Middlesex.

Built mainly in concrete with render and a decorative coating, the property includes an Egyptian gateway, straddled by two kneeling camels, roof top domes and minarets and even a 3,000 year old mummified cat buried in a glass sarcophagus in the domed entrance vestibule.

Overtime further rooms were added to the property. Due to the variety of materials used, the new sections of the property proved to be detrimental allowing water ingress. The rendered surfaces began to crack and coatings flake off.

Recent new owners of the property identified the need to renovate their new home. Sika Limited produced a specification for them and we negotiated the contract for the repair and protection works.

Existing coatings were removed by grit blasting, and water jetting in finer areas.

The remedial works included traditional concrete repairs using a hand placed high-build polymer modified repair mortar, resin injection of cracks and render repairs using modified sand and cement mixes. New movement joints were installed at the changes in substrate materials.

Finally a fairing coat and a decorative elastomeric crack-bridging anti-carbonation protective coating was applied reinstating the home to its former glory.

Stepney Green School

Prior to any works being carried out by us at the school we provided budgetary and programme advice to the school’s building surveyors for the concrete repairs and anticarbonation coatings to all 4 elevations of the 8-storey main block.  Independently the surveyors obtained budgets for the replacement of the existing crittall type windows from SEH Commercial, a national glazing company.

Subsequently we were awarded the contract for both repairs and window replacement to the South Elevation of the block, the first of four phases that were awarded over the following four years.

Like many projects carried out in our schools, programming issues are critical as the works are required to cause as little disruption to the day to day running of the school and often squeezed into school holiday periods.  All works were finally agreed to be carried out to a reduced programme of 6½ weeks with scaffolding commencing within an hour of the school breaking up in late July for the summer holidays.

On a rolling programme, scaffold was erected and the building hammer tested and water jetted whilst school staff removed IT equipment from the rooms affected by the works.  This was followed by window removal and installation of temporary windows that allowed concrete repairs and anti-carbonation coating works to be completed before the new windows were installed.

The repairs and protection to the concrete were carried out using Fosroc HB25, a high build hand placed polymer modified mortar and Dekguard W, a water based acrylic copolymer white anticarbonation coating.

The fibreboard spandrel panels below each window were cleaned, joints made good and sealed and finally coated in one of the school’s corporate colours.

Internal making good, redecoration of the openings and refitting of blinds was followed by school staff finishing with a deep clean internally and reinstatement of equipment ready for the next term to start in early September. The final scaffold was struck and the site cleared within 2 days of the start of new term as planned.

We were awarded contracts for the three remaining elevations in subsequent years with the major works carried out during the summer holidays.  The works to the North Elevation was the most complex due to the requirement to bridge the scaffolding over low level buildings and provide propping within the building.

Southwark Pier Wall

The river wall on the south side of the Thames between HMS Belfast and Southwark Crown Court has undergone many changes in its history including the demolition of the old pier and raising of the wall height for flood prevention.

The wall was constructed from yellow stock bricks that had been protected by render in places, however due to many years of weathering by the tides the exposed areas of masonry had suffered from loss of pointing and failed brickwork.

Following a survey of an 85m length of the wall, carried out on behalf of Her Majesty’s Court Service by Peter Brett Associates, we were awarded the contract for carrying out repairs under the direction of EC Harris LLP.

The planning for the works had to take into account the effect of the tides and was further complicated by the need to satisfy a number of 3rd parties.  These included the Port of London Authority, the Environment Agency, the local authority and the owners of the adjacent areas of land either side of the wall as well as the operations of the Court Service.

Scaffolding was progressively erected along the face of wall, founded on the riverbed and mechanically tied to the wall, with all scaffold boards tied down to prevent movement due to tidal action.

Defective render was removed by use of electric breakers to expose the old brickwork below. Eroded joints were repointed in a fast setting repointing mortar and missing bricks replaced with bricks that matched the existing.  Weed killer was applied to unwanted vegetation.

This was followed by preparation of the surfaces by grit blasting to provide a key followed by the application of a spray concrete containing an alkali free accelerator and reinforced with polypropylene fibres.   The finish was cut to line and trowelled whilst the excess material was cleaned from the scaffold and riverbed prior to the rising tide covering the work.

Other works carried out whilst on site included:

  • Cleaning of sound render by water jetting
  • Replacement of damaged or missing flap valves
  • Installation of replacement mooring chains
  • Mastic joint replacement
  • Removal of redundant timber fenders
  • Recasting sections of the capping beam with a flowable micro concrete

Safestore, Edgware


The Safestore building in Edgware is a large industrial unit comprising a reinforced concrete frame (columns and floor slabs/beams) and brickwork infill panels.

An investigation was carried out by Martech Technical Services to establish the causes and the extent of defective concrete. During this investigation it was identified that the brickwork panels were moving under light hand pressure. After further investigation it came to light that there were no ties between the outer leaf of brickwork and the inner leaf of blockwork in any of the panels.

We were awarded the contract to installed Helifix DryFix remedial wall ties to tie the inner and outer leaves of brickwork together as well as the outer leaf of brickwork to the concrete columns. Specially designed steel wind posts were fabricated and installed at the midpoint of the brickwork panels by our sub-contractor, Artistic Engineering Limited. These were deemed necessary due to the brickwork panels being the largest size that building regulations permit.

In addition to the above issues, the building’s concrete frame was also in a poor state of repair. Following the full site investigation, extensive concrete repairs were undertaken. Furthermore, the concrete frame was provided with corrosion control by the installation of Margel Vapour Phase Inhibitor pellets, a migrating corrosion inhibitor in capsule form, followed by the application of a pigmented anti-carbonation coating. 

Additional works were carried out which included the waterproofing of an external staircase using one of Sika Limited’s flooring products and the removal of 2 no. large window sets and replacement with rendered blockwork.

The building remained occupied throughout with the site foreman working closely with Safestore staff and customers as well as the users of adjoining properties.