|Gillespie, M R, Everett, P A, Albornoz-Parra, L J, and Tracey, E A. 2013. A survey of building stone and roofing slate in Falkirk town centre. Nottingham, UK, British geological Survey. (OR/13/015).|
The British Geological Survey (BGS) has conducted a survey of the building stones and roofing slates in 172 buildings that lie within, and face onto, the Townscape Heritage Initiative (THI) area in Falkirk town centre. The survey was commissioned by Falkirk Council and was conducted by the BGS Building Stone Team in January and February 2013. This report describes the outcomes of the survey. The report also has sections describing a brief assessment of historical quarrying activity in the Falkirk area and the results of stone matching for all the different building stones and slates recorded during the survey. The survey results are presented in this report as a set of maps, but the ‘raw’ survey data have been delivered independently of this report in a Microsoft Excel table and in a shape file suitable for GIS applications. A folder of digital images of the surveyed building elevations has also been delivered independently of this report.
Twenty different building stones were recorded in the THI area: thirteen are buff sandstone, two are orange sandstone, one is limestone, and four are granite.
All of the buff sandstones were sourced from Carboniferous strata that were laid down between 350 and 300 million years ago. Seven come from quarries in the Midland Valley of Scotland and six are from northern England.
The most commonly encountered buff sandstone (‘Buff sandstone 1’, recorded in thirty-six buildings) is the ‘local’ Falkirk stone. This stone was sourced from several quarries to the south of Falkirk, within the Scottish Lower Coal Measures Formation. The oldest surviving buildings (18th Century) in the survey area are constructed from this stone; these are in a vernacular style and are situated in the southern half of the THI area. The youngest surviving buildings containing this stone were constructed in the 1890s. Notable buildings made of ‘Buff sandstone 1’ include Falkirk Old Parish Church (Fa’ Kirk), the Burgh Buildings, and the former YMCA building. It should be possible to obtain new supplies of this local Falkirk building stone from at least one of the original sources: the Bantaskine quarries, just south-west of Falkirk, are still accessible (though overgrown), and consideration should be given to safeguarding this resource.
Six other buff sandstones were sourced from elsewhere in the Midland Valley. The two most commonly encountered ones (‘Buff sandstone 2’, recorded in twelve buildings, and ‘Buff sandstone 4’, recorded in fourteen buildings) were probably sourced from quarries between Denny and Stirling that exploited sandstone beds in the Upper Limestone Formation. All of the buildings constructed from these stones are Victorian residential buildings situated in the northern half of the THI area. The stone would have been transported to Falkirk mainly by canal and railway at this time. ‘Buff sandstone 3’, ‘Buff sandstone 4’, ‘Buff sandstone 5’ and ‘Buff sandstone 6’ are relatively uncommon in the THI area; each was recorded in only three or four buildings. These stones were probably sourced from a number of quarries exploiting several geological formations in the Midland Valley.
The closest-matching currently available stones that could be used for repairs in place of the original buff sandstones from the Midland Valley are mainly from northern England (Derbyshire, Yorkshire and Northumberland); however, several recently re-opened quarries in the Midland Valley supply sandstone that should also provide a good match for some of the original buff sandstones.
All of the sandstone quarries in the Midland Valley had closed by the early part of the 20th century. Stone used in the THI area after that time was sourced from quarries in Derbyshire, Yorkshire and Northumberland. The stone from these quarries has been used mainly in repairs (indents) to older buildings; however, some of these ‘modern’ buff sandstones have been used to build new shop fronts and building extensions, and three of the surveyed buildings (all constructed after 1930) are built entirely of sandstone sourced from northern England.
The two orange sandstones were sourced from quarries in south-west Scotland (Dumfriesshire) that exploited sandstone strata of Permian to Triassic age (~300 to 230 million years old). Orange sandstone was recorded in nine buildings, all of which are relatively prestigious and were constructed between 1890 and 1927; they include St Andrews West Church and the former Railway Hotel (corner of High Street and Kirk Wynd). New supplies of the orange sandstones can still be obtained today from the same quarries that supplied them originally.
One building in the survey area (probably built in the mid-20th century) is constructed of grey shelly limestone (Portland Limestone) sourced from the Jurassic to Cretaceous age (~150 to 140 million years old) Purbeck Formation in Dorset. Several quarries on the Isle of Portland continue to supply this stone today.
The four granite building stones were recorded in just six buildings. Granite masonry forms the base course in four surveyed buildings, the plinth to a statue, and one set of decorative columns framing a doorway. Two of the granite building stones are grey granite and two are pink granite. All four were probably sourced from quarries in Scotland (Aberdeenshire and possibly Kirkudbrightshire and Mull). New supplies of two or three of the granites can probably be obtained from currently active quarries in Aberdeenshire. An overseas source may be able to provide a good match for the fourth granite.
Six different roofing slates were recorded in the survey area; two are from Scotland (Scottish West Highland slate and Scottish Highland Border slate), two are from Wales (‘Welsh grey’ and ‘Welsh purplish’ slate), one is from the English Lake District (Cumbria), and one is from Spain. Scottish slate was recorded in forty-eight buildings, Welsh slate in thirty-seven buildings, Cumbrian slate in four buildings and Spanish slate in fifteen buildings. Slate is not currently produced in Scotland, and recycled slate (from buildings undergoing repair or demolition) would provide the best source of new Scottish slate to use in repairs. Welsh grey slate would be the closest-matching currently available slate if recycled Scottish slate is not available. Welsh grey and Welsh purplish slate, Cumbrian slate and Spanish slate are all currently being supplied by operating quarries, and it should be easy to obtain new supplies to use in repairs and new-build construction.