Historic station vent gets Mapei make-over

A Mapei concrete repair and coatings system has been used to renovate a historic out-of-ground vent at Old Street station.  Works were carried out by Bryen & Langley for Transport for London (TFL). The Mapei specification included repair mortars and mesh, render, primer and Silancolor Tonachino - a highly protective, textured, silicone resin-based coating.

Situated on the Bank branch of the Northern Line, Old Street is one of London’s busiest stations, serving around 18 million passengers each year. The station – and the roundabout from which Old Street is accessed – is currently being transformed by owner, TFL.  Repair and renovation of the protruding air vent forms part of the above ground works.

To repair the concrete surface of the vent, two Mapei mortars were applied: Mapei’s Planitop 200 – a fine-grained water-repellent cementitious skimming mortar and

Planitop FAST 330 – a quick-setting, very low VOC, fibre reinforced cementitious levelling mortar.  Mapefer 1K ZERO* - a one-component mortar made from cementitious binders, powdered polymers and corrosion inhibitors – was also applied to the vent’s steel reinforcement to prevent the formation of rust and as an adhesion promoter for the mortar used to repair the concrete.  Alkali-resistant glass fibre mesh, Mapetherm Net, was also applied to reinforce the skim coat. 

Following the concrete repair, Mapei Mapewall GPR general purpose render was applied to the vent, to smooth the surface before application of Silancolor Primer – a breathable, siloxane undercoat with a smooth finish. The vent was then finished with Silancolor Tonachino - a highly protective transpirant and water-repellent textured siloxane coating that creates a mould and mildew-resistant rustic-effect finish.

*CO₂ emissions - measured throughout the life cycle of products from the Zero line in 2024 using Life Cycle Assessment (LCA) methodology, verified and certified with EPDs - have been offset through reforestation projects and protection of biodiversity. The Zero line portfolio demonstrates Mapei’s commitment to the planet, to people and to biodiversity. 

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