Project: Glasgow University
Location: 50-58 Hillhead Street & 73-81 Great George Street, Glasgow
Main Contractor: Morris & Spottiswood
Supplier: SIG Roofing – James O’Hara
Products: SIGA 120 random diminishing slate from the SIGA Prestige range, Tyvek Supro Felt, BLM lead, Hargreaves Cast Iron Rainwater Goods
Type of property: Educational/Commercial 2,500 M2
Date completed: October 2023
Background:
Since 2020, a dedicated team within the University of Glasgow has carefully assessed the condition of their existing assets, highlighting the critical need to invest in their historic buildings.
Part of this project involved preserving the properties on Hillhead Street and George Street to protect the University’s architectural heritage for future generations. The project included making external repairs to the buildings on Hillhead Street and Great George Street to ensure they were protected from the weather. The focus was on enhancing the buildings’ sustainability and thermal performance.
The work included the large roofing area of the building block, and specific guidelines were provided for selecting products to preserve the site’s cultural heritage. The project required products that would enhance the existing 19th-century style while meeting modern sustainability and thermal performance standards. Each product was carefully chosen based on its technical specifications in the market and budget was also a consideration, as Glasgow University is a not-for-profit organisation that prioritises optimising limited budgets.
Roofing product choice:
Great George Street is located within the Glasgow West End Conservation Area. Selected products needed to blend seamlessly into the local heritage and respect the craftsmanship evident in the area. With a project roofing area of 2500m², traditional Scottish slate was not an option, while the SIGA 120 had just the right blend of quality, style and appearance to fit perfectly into the conservation area.
DM Roofing (DMR) of Kilmarnock specialise in listed and historically important building roof restorations. The team in AccuRoof, the specification division of SIG Roofing, supported the contractors when identifying which slate would fit the project best. SIGA 120 was proposed as a quality slate with the right logistical support for the project needs as it was readily available from stock to hit the project timescales.
SIGA 120 is a textured, dark blue/grey slate that is a random diminishing alternative to traditional Scottish Slate. One of our thickest slates at 7-9mm, SIGA 120 is supplied in blank, random-widths and diminishing length courses to suit your project, reducing labour and providing an authentic roof finish. Sourced in Wales, it is an alternative to Scottish Ballachulish slate and has Snowdonia National Park approval. As part of the Prestige range of slate from SIG Roofing, all SIGA 120 slates conform to EN 12326-1:2014 and have a representative performance of Thermal Cycling T1, Exposure SO₂ S1 & Water Absorption W1 (≤0,6%).
For this project, SIG Roofing were able to offer a 100-year warranty on the SIGA 120 Slate, it is also recyclable, so it can be stripped off and reused.
See more details on the SIGA products at https://www.sigaslate.co.uk/
Installation:
The work included replacing the existing roof coverings with a traditional slate finish, overhauling the traditional timber-framed windows, and addressing the defective rainwater goods. The project also included removing and renewing all sarking boards in conjunction with slate replacements. At the same time, other contractors were involved in carrying out render repairs and leadworks to the valleys, gutters, hips, Velux windows, and skylights.
Although the slating of the roof did not present too many difficulties, it was the scale of the area that provided the biggest challenge. The roof area was vast and although there were various large areas of pitched roofing there was just as much time spent on the smaller more intricate turrets and vertical panels.
Prior to delivery, the slates were sorted, graded, and holed where necessary as per BS 5534 and BS 8000. They were sorted into different thicknesses, and odd slates were set aside for use on eaves or as top slates. The slate is holed from the back, creating a countersunk area that allows the nail head to sit neatly and increases waterproofing and longevity.
The project benefitted from the expertise of DMR’s experienced team on this project.
Logistical challenges:
The University is a hive of activity, with the streets surrounding the property full of the hustle and bustle of student and city life. The building also remained occupied during the renovation work, which created access challenges.
Therefore, specific delivery times were allocated to the project team to avoid congestion, which required tight management of the bill of materials. DMR worked closely with the SIG Roofing branch in Linwood to ensure that logistics fitted the narrow delivery windows and loads were dropped off on time and in full.
On site materials management came to the fore with this project too. Each phase had a strict timeline and with street restrictions limiting the space dedicated to storage, the contractors had to work closely with the SIG Roofing branch to deliver the slate in a steady flow, including certain sizes to account for the length of the roof.
As the one reliable facet of Scottish weather is rain, it was critical to ensure the roof remained watertight at all times. A particular concern were the turrets, as cutting the sarking board was a painstakingly detailed process, each board needed to be trimmed into a precise tapered shape which took time and skilled patience. This could have delayed the project significantly, but the phased planning allowed the team to work diligently through each section without undue disruption to other contractors and the building’s inhabitants.
Teamwork between contractors, colleagues and suppliers was the essential ingredient in delivering this project successfully. There were a number of different contractors covering stonework, windows and internal fitouts. This presented a logistical imperative to coordinate all moving parts into a well-structured, phased, approach.
The project was delivered on time and within the budget allocated for the roof work.
