# Carrstone

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{{Short description|Sedimentary sandstone conglomerate formed during the Cretaceous period}}
'''Carrstone''' (or '''carstone''', also known as '''Silsoe''', '''heathstone''', '''ironstone''', '''honeystone''' or '''gingerbread''') is a sedimentary [sandstone](/source/sandstone) conglomerate formed during the [Cretaceous period](/source/Cretaceous_period). It varies in colour from light to dark rusty ginger. Used as a building stone it can be found in [Bedfordshire](/source/Bedfordshire), [Cambridgeshire](/source/Cambridgeshire) and extensively in the historic buildings of northwest [Norfolk](/source/Norfolk).<ref>University of Southampton Archaeology, Stone in Archaeology Database.</ref><ref>Messent, C. W. J, Rev. 1967, ''A Thousand Years of Norfolk Carstone 967–1967'', Fletcher & Sons.</ref>

Carrstone can vary in quality depending on factors such as the degree of [iron oxide](/source/iron_oxide) present, and sufficient pressure to form the matrix. Carrstone can also phase into [puddingstone](/source/Puddingstone_(rock)), [ferricrete](/source/ferricrete) and silver carr. Because of its variations it does not lend itself to carving or finer work.<ref>Clifton-Taylor A., & Simmons, J. 1987. ''The Pattern of English Building''</ref> Carrstonework can be seen in forms such as: random carrstone, coursed carrstone, ashlared carrstone, all with, or without, [galleting](/source/galleting). Other patterns of use are: rough carrstone sipps  (slips, shale or brickettes) and cut carrstone sipps, both used in masonry fields between brickwork quoins.<ref>Hart, Stephen. 2008, ''Flint Flushwork, a Medieval Masonry Art'', p. 25, Boyden Press.</ref>

thumb|Carrstone used in construction

Cut carrstone sipps or shales are used extensively at [Sandringham House](/source/Sandringham_House) on the main building and the stables block. Other examples of carrstone work can be found on [St Mary's Church, Barton Bendish](/source/St_Mary's_Church%2C_Barton_Bendish) as well as many other parish churches in the region.<ref>Allen, R. L, 2004, ''Carrstone in Norfolk Buildings'', Archaeopress.</ref> [Hunstanton](/source/Hunstanton) and [Wolferton](/source/Wolferton) feature some interesting examples along with the 'Gingerbread Town' of [Downham Market](/source/Downham_Market), notably the [Grade II listed](/source/Grade_II_listed) [Downham Market railway station](/source/Downham_Market_railway_station).

Due to easy access to river transport, Carrstone can occasionally be found outside this region in such places as [Great Bentley](/source/Great_Bentley) Church, [Colchester](/source/Colchester), [Essex](/source/Essex).

[[File:Carrstone at Hunstanton.jpg|thumb|Carrstone in the cliffs at [Hunstanton](/source/Hunstanton)]]

== Petrography of carrstone formation ==
[Ferruginous](/source/Iron_oxide) sandstone with detrital framework grains. [Quartz](/source/Quartz) dominated with subordinate [feldspar](/source/feldspar), [glauconite](/source/glauconite) and sporadic phosphatic grains.<ref>{{cite web |url=http://www.nora.nerc.ac.uk |title=Archived copy |accessdate=2014-01-07 |url-status=dead |archiveurl=https://web.archive.org/web/20140106134819/http://nora.nerc.ac.uk/ |archivedate=2014-01-06 }} retrieved 15-3-2011</ref>

== Silver carr ==
Silver carrstone is, by comparison to ginger carrstone, rare. It is quarried alongside ginger and some even rarer pieces display both colours. The stone is a [concretion](/source/concretion) which was generally quarried at [Castle Rising](/source/Castle_Rising) woods, Norfolk. Many of the buildings in Castle Rising, [Hillington](/source/Hillington%2C_Norfolk) and [Flitcham](/source/Flitcham%2C_Norfolk) have examples of silver carr used as a building material. Due to the proximity of the river, the stone was transported to other locations such as [Burgh Castle](/source/Burgh_Castle), Norfolk.
thumb|Silver carrstone alongside ginger carrstone

== Carrstone iron ore ==
[East Anglia](/source/East_Anglia) has had only four workable pockets for [iron production](/source/iron_production). The Carrstone found in Norfolk at [Ashwicken](/source/Ashwicken) and [West Runton](/source/West_Runton) was considered viable for iron smelting by the [Romans](/source/Ancient_Rome).<ref>Tylecote, R. F., 1986, ''The Prehistory of Metallurgy in the British Isles'', Institute of Metals, London.</ref> There is also evidence of smelting carrstone in the 14th century at [Blakeney Chapel](/source/Blakeney_Chapel). These were nodular ores which were burnt by the direct method with [charcoal](/source/charcoal) in a bloomery furnace with forced air; the [iron bloom](/source/iron_bloom) was taken from the furnace as a spongy mass which was filled with unwanted impurities, these were worked (wrought) out by hand to produce [wrought iron](/source/wrought_iron).<ref>Tylecote, R. F., 1992. ''A History of Metals'' 2nd ed., Institute of Metals. 46–57, 62Ω–66.</ref>

== Carrstone quarries ==
Historically, there have been numerous carrstone quarries along the Carrstone belt.<ref>Taylor & Francis 1835, ''Philosophical Magazine & Journal of Science'' Pp. 177–179. London</ref><ref>{{cite web|url=http://www.naturalengland.org.uk |title=GOV.UK |publisher=Natural England |date= |accessdate=2016-11-26}}</ref> [Snettisham](/source/Snettisham) Carrstone quarry in Norfolk is still active and produces high [iron](/source/iron) content building stone.<ref>{{cite web |url=http://build.uk/ |website=build.uk |access-date=22 May 2022 }}</ref>

== Conservation of carrstone buildings ==
[[File:St Mary Magdalene, Sandringham 05.jpg|thumb|[St Mary Magdalene Church, Sandringham](/source/St_Mary_Magdalene_Church%2C_Sandringham), considered a noteworthy example of a carrstone building]]
Carrstone, as with many other building stones, is vulnerable to decay.<ref>Ashurst, J. & N., 1998, ''Practical Building Conservation'', Volume 1, English Heritage, London.</ref> There are many factors which influence the life of carr building stone such as the bedding mortar,<ref>SPAB, 2002, Technical Pamphlet 5 ''Repointing Stone and Brick Walling'', London</ref> moisture control<ref>SPAB, 1998, The Control of Damp in Old Buildings, London.</ref> and orientation of stone.<ref>Ashurst, J. & N., 1998, ''Practical Building Conservation'', Volume 1, English Heritage, London</ref>
Appearance of carr building stone can also be affected by factors such as mortar colour, mortar inclusions, stone shade, orientation in the wall, galletting and shapes of stone.<ref>Ashurst, J., & Francis, D., 1998. ''Conservation of Building and Decorative Stone''. Butterworth-Heienmann</ref>

== Construction methods ==
Carrstone can be used in much the same way as any other building stone, but with the disadvantages of [friability](/source/friability)<ref>Brewster, D., Taylor, R., Philips, R., 1835, ''Philosophical Magazine & Journal of Science'' VII pp. 177–179</ref> and of being more difficult to cut by hand. Whilst the stone is used as a single leaf for newbuild to reflect the more [vernacular](/source/Vernacular_architecture) buildings, it is more common to see traditional methods of construction which involve an inner and outer leaf with a rubble core fill.

This type of wall is referred to as 'solid wall construction', but this is a misleading description due to the two leaves and core fill having different properties from a true solid wall, which is more susceptible to [condensation](/source/condensation) and other damp mechanisms such as penetrating and [rising damp](/source/rising_damp).

== References ==
{{Reflist}}

Category:Sandstone

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Adapted from the Wikipedia article [Carrstone](https://en.wikipedia.org/wiki/Carrstone) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Carrstone?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.