Project overview

Dumas House in West Perth was constructed in the mid-1960s and is Heritage Council of WA listed. The building has two basement levels, a ground floor with entry lobby and support areas and 14 office accommodation levels. Over 49 years, the heat, cold, wind and rain had deteriorated the building’s exterior in its exposed position north of Kings Park; the materials had reached the end of their useful life and needed to be repaired or replaced.

Project requirements

Repair of the reinforced concrete sub-structure for the 14-storey State Government office building in West Perth. This work was undertaken while the building was occupied.

Scope of work

  • Spandrel panel replacement (cracking of existing concrete)
  • Masonry wall restoration
  • Column, slab edge and gutter concrete repairs 
  • Life expectancy of materials & durability requirements – 20 years’ warranty for the Silane Treatment applied in multiple coats. Protect against future dilapidation of the structure due to the development of ASR. Manage the risk
  • Low cover issues – sometimes no cover

Sika solutions

  1. Rebar treatment, patch repairs – Sika Monotop 910 (250kg) applied as part of the concrete repair process.
  2. Low cover barrier protection – Sikadur 33, thin coat over any visible surface exposed steel bars (isolated).
  3. Structural concrete repairs – Sika Monotop 352NFG (7m³), Sika Monotop 412NFG (13m³), Sika Monotop 436N (11m³).
  4. Cosmetic concrete repairs – Sika Monotop 723N & Sika Monotop FC (<1m³)
  5. Impregnation to control moisture ingress (structural columns) – Sikagard 706 Thixo & Sikagard 550W Elastic. Applied to column concrete surfaces after repairs and before reinstatement of the new terrazzo stone cladding panels. New ingress controls and bottom panel venting to aid shedding of any moisture collecting behind the panels.
  6. Impregnation to control moisture ingress (spandrel beams) – Sikagard 706 Thixo & Sikagard 550 W Elastic. Applied to the concrete repaired faces prior to the installation of the new precast spandrel panels.

Project participants

Project owner: WA State Government, Department of Finance

Architect: Grifiths Architects, Mr Brandon Pratley

Engineer: (Durability & Heritage Consultant) Quoin

Contractor: Duratec

Products used

  • Sika Monotop range
  • SikaGard-706 T
  • SikaGard-550 W Elastic
  • SikaDur-33
  • Sikadur-52