St Andrew Holborn

St Andrew Holborn has stood as a Catholic Church for over 1000 years. Throughout its history it has received several major renovations, but it is most famously known for its late 17^th century rebuild by the renowned architect Christopher Wren, who later went on to design one of London’s most recognisable and historic landmarks, St. Paul’s Cathedral. The latest large-scale works date back to the 1950s, and six decades on it was deemed in need of repair again.

Completed at the end of 2018, the latest refurbishments spanned the entire internal area of the church, including some 600m² of flooring in the main church area and its surrounding rooms, as well as its vestibules and tower. Consisting of old vinyl tiling, it was worn and damaged and was replaced with new Hopton Wood Limestone, which was installed by Chichester Stoneworks. The existing base was also removed and replaced with a high-strength, rapid drying screed that could work within the client’s limited time constraints.

Having used ARDEX products on several other successful projects, Chichester Stoneworks contacted the ARDEX Business Development Team for specification advice. A full site visit helped ARDEX to understand the project and client requirements, who also provided compatibility testing between the limestone and potential fixing solutions. They provided the following specification:

• ARDEX A 38 Ultra Rapid Drying Cement for Internal and External Screeds
  With RAPIDRY FORMULA Technology, ARDEX Screed Cements can be trafficked in 3 hours and natural stone installed after just 4 hours, regardless of thickness. An ARDEX Screed helps to significantly reduce project downtime in comparison to traditional sand and cement screeds, which can require months of drying before subsequent work can begin.




• ARDEX A 18 Screed Bonding Cement with Colour Indicator
  Provides a maximum adhesion strength bond between ARDEX Screed Cements and the substrates they are applied to, and a built-in colour indicator ensures screeds aren’t mistakenly applied into dry bonding slurries.




• ARDEX K 15-HB High Build Raid Drying Levelling Compound
  ARDEX K 15-HB can be applied from 5mm up to 35mm in single layer and is walkable after 2 hours regardless of thickness and provides a quick and flexible levelling solution. Like ARDEX S 28 Tile Adhesive below, it also incorporates RAPIDRY FORMULA Technology, helping to prevent moisture damage in moisture-sensitive natural stones like Limestone.




• ARDEX S 28 MICROTEC Flexible Rapid Set Semi-Pourable Floor Stone & Tile Adhesive
  Natural stone tiles, including Limestone, are susceptible to moisture damage caused by water migrating into them from the adhesive used to install them, and this can present as unsightly and permanent staining on the face of the tile and even warping of the tile body itself. Incorporating RAPIDRY FORMULA Technology, ARDEX S 28 locks the mix water in to prevent this from happening and helps to ensure a risk-free installation. It is also semi-pourable to help solid bed fix floor tiles with ease.




• ARDEX-FLEX FS Flexible Standard Set Tile Grout for Narrow Joints
  ARDEX-FLEX Tile Grouts are blended to a uniform consistency to provide consistent, streak-free results; and with 35 colours available, there’s a shade to suit any installation.

Before the tiling commenced, ARDEX also provided guidance on the use of the tiles, with a detailed report to summarise the compatibility testing they completed. For example, the Hopton Wood Limestone was reinforced by a resin mesh backing, and it was advised this be removed in accordance with Stone Federation guidance.

Support continued throughout the project, with the ARDEX Business Development Team always on-hand to provide specification advice and answer questions when required.

The works completed in December. Commenting on ARDEX’s involvement in the project, Chris Gladwell of Chichester Stoneworks said, “St Andrew Holborn has been an interesting and challenging project as we needed to install a new stone floor within the constraints of an existing building. Throughout the process ARDEX gave us technical support and advice on how to overcome some of the challenges we faced and assisted us with formulating a suitable specification for the screed, adhesive and grouts used.”