A former hotel in the Polwarth area of Scotland’s capital is the subject of a complex conversion and reconfiguration project, where Marmox Thermoblocks have been specified by the project consultants to address the critical floor/wall junction within the new extensions being constructed.
Edinburgh based architectural practice, Morgan McDonnell is renowned for both its new-build and refurbishment work across the city and ‘Old Town’. In the case of the Ettrick Hotel, its client – developer Northumberland Street Mews Ltd. Is creating 6 new residential units within the existing building plus a further 4 across the two extensions.
At the base of the new perimeter walls, the block-layers have used a total of 117 of the 140mm wide Thermoblock units each one 600mm long and 65mm high. In addition, the merchant stockist involved, St. Andrews Building and Timber also supplied a carton of 10 Marmox MSP 360 Sealant for the purpose of completing the stepped joints.
The Project Architect for Morgan McDonnell, Alice Hibberd commented:
“We have specified Marmox Thermoblocks for other projects in the past and chose them in this case as part of our detailing to address the area where a thermal bridge might occur.”
The site agent, Daren Colvin, confirmed:
“We are using Thermoblocks in new external walls inner leaves at the ground floor slab level and also at parapet level. The blocks provide us with a simple effective means of forming thermal breaks.”
Each section of Thermoblock is comprised of ultra-high performance XPS insulation, encapsulating miniature columns of concrete, while the top and bottom are covered by alkali resistant glass-fibre mesh, retaining a surface of fibre reinforced polymer concrete to facilitate bonding.
The concrete columns have a very low conductivity so do not present thermal bridges themselves and when coupled with the highly insulating XPS insulation core, a combined thermal conductivity of 0.47W/mK is achieved.
Crucially, being able to employ a defined, very low thermal transmittance – derived by thermal modelling or measurement – offers a far more advantageous result than adopting the ‘default’ figure offered in SAP which can often result in non-compliance under the Building Regulations or the Building Standards for Scotland.