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C & G BUILDING SOCIETY, YEOVIL, SOMERSETShort Story:The Cheltenham and Gloucester Building in Yeovil, Somerset, was originally built using reconstituted ‘Yeovil Stone’ faced precast concrete blocks and features. Unfortunately after many years the steel has started to corrode where the stone facing mix and then the backing concrete had gradually carbonated and lost its protective alkalinity. To repair the damage and provide future protection, CS2 surveyors chose a complete Remmers system and Concrete Repairs Limited was the successful tendering contractor. Any corroding steel was cleaned, primed and the areas repaired with Remmers’ Mortar, carefully colour matched to the original. Finally the surfaces were protected with Remmers’ gel hydrophobic impregnation, to prevent any further water ingress. Full Story: The Cheltenham and Gloucester Building in Yeovil was originally built using reconstituted ‘Yeovil Stone’ facing blocks and feature details. ‘Yeovil Stone’ is similar to Portland Stone but a warmer yellow colour. This included all of the fair faced areas, the window surrounds with mullions and cills etc, that also hold the leaded glazing units, and all of the roof level feature details. The precast units were all cast upside down, with the reconstituted stone facing mix placed into the moulds first, followed by the steel reinforcement and the casting concrete. Unfortunately during casting some of the steel had moved unnoticed into the 20mm facing mix, so after some years of exposure on the building, the natural carbonation front had progressed through the facing mix and into the backing concrete. The steel had then started to corrode in these carbonated areas causing cracking and spalling of the concrete surfaces. To halt and repair the developing damage and ensure that it was protected in future, the surveyors from CS2 derived a solution with a complete Remmers’ system. Concrete Repairs Limited (CRL) were the successful contractor and they first carried out hammer testing together with the engineers, to fully identify all damaged areas in need of repair, and these were measured and recorded. The damaged areas were broken out to expose any corroding steel, which was cleaned and primed. Remmers’ Restoration Mortar was then used to repair the damage back to its original line and profile; this was carefully colour matched to the original Yeovil Stone surfaces. This advanced mortar is also easily tooled and finished, so CRL were able to provide the desired surface texture and profile to blend in with the adjacent unrepaired areas. Finally all of the façade surfaces were protected by the application of Remmers’ colourless hydrophobic impregnation to prevent any further water ingress and corrosion. This was supplied in a unique gel formulation that optimises penetration and prevents spillage or mess on other areas or surfaces.
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