Editing Slate (section)

===Construction===
[[File:St Fagans Tannery 7.jpg|thumb|A slate roof in [[Cardiff]], Wales]]
[[File:Kirche wurzbach.jpg|thumb|A slate-faced church and homes in [[Wurzbach]], Germany]]
[[File:St.leonhard-ffm002.jpg|thumb|upright|A fine slate tile work, Saint Leonhard's Church in [[Frankfurt am Main]], Germany]]
[[File:SlateTremedda.jpg|thumb|Slates with holes at a farm in [[Tremedda]], [[Cornwall]], England]]
[[File:Sirrako slate roof.jpg|thumb|A slate roof in [[Syrrako]] (Greece), built with a curved valley layout and weight stones on top.]]
Slate can be made into roofing slate, a type of [[Roof tiles|roof tile]] which are installed by a [[slater]]. Slate has two lines of breakability—cleavage and grain—which make it possible to split the stone into thin sheets. When broken, slate retains a natural appearance while remaining relatively flat and easy to stack. A series of "slate booms" occurred in Europe from the 1870s until the [[World War I|First World War]] following improvements in railway, road and waterway transportation systems.<ref>{{cite book|last1=Schunck |first1=Eberhard |first2=Hans Jochen |last2=Oster |title=Roof Construction Manual Pitched Roofs |location=Basel |publisher=De Gruyter |date=2003 |page=12 |edition=print}}</ref>

Slate is particularly suitable as a roofing material as it has an extremely low water absorption index of less than 0.4%, making the material resistant to frost damage.<ref name=NPS>{{cite web |last1=Chavez |first1=Mark |date=2013 |title=Should I Replace My Slate Roof with a Synthetic? |url=https://www.nps.gov/articles/should-i-replace-my-slate-roof-with-a-synthetic.htm |website=National Park Service |access-date=28 June 2021}}</ref> Natural slate, which requires only minimal processing, has an [[embodied energy]] that compares favorably with other roofing materials.<ref>{{cite journal |last1=Crishna |first1=N. |last2=Banfill |first2=P.F.G. |last3=Goodsir |first3=S. |title=Embodied energy and CO2 in UK dimension stone |journal=Resources, Conservation and Recycling |date=October 2011 |volume=55 |issue=12 |pages=1265–1273 |doi=10.1016/j.resconrec.2011.06.014}}</ref>
Natural slate is used by building professionals as a result of its beauty and durability. Slate is incredibly durable and can last several hundred years,<ref>{{cite journal |last1=Cárdenes |first1=Víctor |last2=Cnudde |first2=Jean Pierre |last3=Wichert |first3=Jörn |last4=Large |first4=David |last5=López-Mungira |first5=Aurora |last6=Cnudde |first6=Veerle |title=Roofing slate standards: A critical review |journal=Construction and Building Materials |date=July 2016 |volume=115 |pages=93–104 |doi=10.1016/j.conbuildmat.2016.04.042}}</ref> often with little or no maintenance.<ref name=NPS/> Natural slate is also fire resistant and energy efficient.<ref>[http://www.insightmag.co.uk/newsarticle.asp?NewsID=286 Natural Slate, the natural option] {{webarchive|url=https://web.archive.org/web/20140310123813/http://www.insightmag.co.uk/newsarticle.asp?NewsID=286 |date=10 March 2014 }}</ref>

Slate roof tiles are usually fixed (fastened) either with nails or with hooks (as is common with Spanish slate).<ref>{{cite web |title=Slate Design and Fixing Guide |url=https://www.ssqgroup.com/wp-content/uploads/2022/12/SSQ-Natural-Slate-Design-Fixing-Guide.pdf |access-date=28 June 2021 |publisher=SSQ Group}}</ref> In the UK, fixing is typically with double nails onto timber battens (England and Wales)<ref>{{cite web |title=Natural roofing slate design and fixing guide |url=https://www.ssqgroup.com/wp-content/uploads/2022/12/SSQ-Natural-Slate-Design-Fixing-Guide.pdf |url-status=live |archive-url=https://web.archive.org/web/20190626011731/http://ssqslate.com/wp-content/uploads/2012/10/SSQ_Slate_Fixing_Guide_Nail_Fixings.pdf |archive-date=2019-06-26 |access-date=28 June 2021 |publisher=SSQ Group |page=8}}</ref> or nailed directly onto timber sarking boards (Scotland and Northern Ireland).{{citation needed|date=June 2021}} Nails were traditionally of copper, although there are modern alloy and stainless steel alternatives.<ref>{{cite web |title=6 Basic Principals of Slate Roofing |date=3 August 2017 |url=https://slateassociation.org/6-basic-principals-slate-roofing/ |publisher=National Slate Association |access-date=28 June 2021}}</ref> Both these methods, if used properly, provide a long-lasting weathertight roof with a lifespan of around 60–125 years.<ref name=NPS/>

Some mainland European slate suppliers suggest that using hook fixing means that:<ref>{{usurped|1=[https://archive.today/20120912003254/http://www.spanishslateuk.com/hook_fixing.asp Galician and Spanish Slate website "Hook Fixing"]}}. Retrieved on 26 January 2010 {{usurped|1=[https://web.archive.org/web/20110716113747/http://www.spanishslateuk.com/hook_fixing.asp archived]}}</ref>
* Areas of weakness on the tile are fewer since no holes have to be drilled
* Roofing features such as valleys and domes are easier to create since narrow tiles can be used<ref name=SSQHook>{{cite web |title=Hook fixing |url=http://ssqslate.com/wp-content/uploads/2013/05/SSQ_Slate_Fixing_Guide_Hook_Fixings.pdf |archive-url=https://web.archive.org/web/20190626010851/http://ssqslate.com/wp-content/uploads/2013/05/SSQ_Slate_Fixing_Guide_Hook_Fixings.pdf |archive-date=2019-06-26 |url-status=live |publisher=SSQ Group |access-date=28 June 2021}}</ref>
* Hook fixing is particularly suitable in regions subject to severe weather conditions, since there is greater resistance to wind uplift, as the lower edge of the slate is secured.<ref name=SSQHook/>

The metal hooks are, however, visible and may be unsuitable for historic properties.{{citation needed|date=May 2025}}

Slate tiles are often used for interior and exterior flooring,<ref name=bobvilafloor>{{cite web |last1=Taylor |first1=Glenda |last2=Vila |first2=Bob |title=All You Need to Know About Slate Floors |url=https://www.bobvila.com/articles/slate-floors/ |website=bob vila |date=11 August 2016 |publisher=Action Media, Inc. |access-date=28 June 2021}}</ref> stairs,<ref>{{cite web |last1=Robinson |first1=Kristy |title=Installing Slate Tiles on Front Stairs |url=https://homeguides.sfgate.com/installing-slate-tiles-front-stairs-33718.html |website=SFGate |date=2 July 2012 |publisher=Hearst |access-date=28 June 2021}}</ref> walkways<ref>{{cite web |title=How to Lay a Walkway with Slate Pavers |url=https://www.doityourself.com/stry/how-to-lay-a-walkway-with-slate-pavers |website=doityourself |access-date=28 June 2021}}</ref> and wall cladding.<ref>{{cite web |last1=Asaff |first1=Sarabeth |title=How to Install Exterior Slate Tile |url=https://homeguides.sfgate.com/glass-tile-thickness-make-difference-92797.html |website=SFGate |date=December 2013 |publisher=Hearst |access-date=28 June 2021}}</ref> Tiles are installed and set on mortar and grouted along the edges. Chemical sealants are often used on tiles to improve durability and appearance,<ref name=thespruce/> increase stain resistance,<ref name=bobvilafloor/> reduce [[efflorescence]], and increase or reduce surface smoothness. Tiles are often sold gauged, meaning that the back surface is ground for ease of installation.<ref name=thespruce>{{cite web |last1=Lewitin |first1=Joseph |title=Everything You Need to Know About Slate Flooring Tiles |url=https://www.thespruce.com/all-about-slate-flooring-tiles-1314931 |website=The Spruce |publisher=Dotdash |access-date=28 June 2021}}</ref> Slate flooring can be slippery when used in external locations subject to rain.{{citation needed|date=May 2025}}

Slate tiles were used in 19th century UK building construction (apart from roofs) and in slate quarrying areas such as [[Blaenau Ffestiniog]] and [[Bethesda, Wales|Bethesda]], [[Wales]] there are still many buildings wholly constructed of slate. Slates can also be set into walls to provide a rudimentary [[Damp proofing|damp-proof membrane]]. Small offcuts are used as [[Shim (spacer)|shims]] to level floor joists. In areas where slate is plentiful it is also used in pieces of various sizes for building walls and hedges, sometimes combined with other kinds of stone.{{citation needed|date=May 2025}}