Quarried stone that outlives the people who lay it. Which slate goes on an Irish roof, what Killaloe is and why it still matters, and how to match a hundred-year-old slate you cannot buy any more.
Natural slate is quarried stone, shaped by geological processes over millions of years. Each slate is unique in texture, thickness and colour variation. Synthetic slate is manufactured from fibre cement, recycled rubber or plastic composites and is designed to mimic the appearance of natural slate at a lower cost.
The lifespan difference is significant. Natural slate lasts 80 to 150 years, and there are Victorian roofs across Dublin, Limerick and Cork still covered in their original slates. Synthetic slate lasts 25 to 50 years, depending on the product. Visually, synthetic slate tends to look uniform and can appear slightly plastic compared to the varied texture of natural stone. For period properties, conservation areas or buildings in historic streetscapes, natural slate is usually the only appropriate choice. Local authorities and conservation officers will often specify natural slate for protected structures.
Find a Slate Roofer
Three of the four coverings an Irish roofer will offer. Irish Killaloe is the fourth, and it is sourced differently to any of these.
Fibre Cement and Composite
25 to 50 years
Manufactured from fibre cement, recycled rubber or plastic composites and designed to mimic the appearance of natural slate at a lower cost. It tends to look uniform and can appear slightly plastic compared to the varied texture of natural stone, which is why it is rarely the right answer on a period property or in a conservation area.
Spanish Galician Slate
50 to 100 years
The most commonly specified natural slate on new and replacement roofs in Ireland today. Galician geology produces a dark grey to blue-black stone similar in character to Irish stone, which is why it has become the default import. Quality varies between quarries, and the best of it is graded S1 under EN 12326 with very low water absorption.
Welsh Slate
80 to 150 years
A premium product from the Penrhyn and Ffestiniog quarries in north Wales. The distinctive purple-grey colour is lighter than Spanish or Irish slate and suits Victorian and Edwardian properties. Commonly specified for high-end restoration and period conversions where authenticity is the priority, and the closest match to original Irish slate where Killaloe is unavailable.
Killaloe slate is quarried near Lough Derg in County Clare and is one of the finest roofing slates produced anywhere in Ireland or Britain. It is a dense, dark blue-black stone with excellent frost resistance, ideally suited to the Irish climate. Georgian and Victorian buildings throughout Ireland were originally roofed in Killaloe slate, and it remains the most authentic choice for restoration work on pre-1900 properties.
Killaloe slate is still available but supply is limited and prices are at a premium compared to imported slate. If you are repairing or restoring a building that originally had Killaloe slate, specifying Irish stone maintains the character of the building and supports local heritage. It also reduces transport carbon compared to stone shipped from Spain or Wales.
Ask your roofer to source Killaloe slate from a reputable Irish supplier and request a sample before ordering to confirm colour and thickness match your existing roof.
Installed rates for 2026, covering stripping the existing covering, new breathable felt underlay, treated battens and laying the new slate. Scaffold is normally a separate line, so confirm whether it is inside the quote before comparing two prices.
Cheapest
Fibre Cement Slate
from €45
Lowest cost per metre, shortest lifePer m², supplied and installed
Middle of the Road
Spanish Galician Slate
from €60
Natural stone at a workable pricePer m², supplied and installed
Real quarried stone with decades of service life, at a rate most re-roofs can carry. It is the default specification in Ireland for that reason.
Most Expensive
Welsh or Killaloe Slate
from €90
Restoration and conservation workPer m², supplied and installed
A partial re-slate covering half a typical semi-detached roof, roughly 35 square metres, in Spanish slate will typically cost €3,000 to €8,000 depending on access and the condition of the structure beneath. Individual slate replacement during a repair visit costs from €80 per visit plus materials. Always factor in scaffold for any roof work above single storey level, which adds €800 to €2,000 but is non-negotiable from a safety standpoint.
Matching existing slates is one of the most important and underappreciated aspects of slate roof repair. Colour, texture and thickness all vary between slate types, quarries and even different batches from the same quarry, so a patch repair using the wrong slate looks obviously wrong and can affect the property's appearance and value.
A Patch Repair Works When
Re-Slate Instead When
Salvaged slates from reclamation yards are often the best match for older roofs. Reclamation yards across Ireland stock slates salvaged from demolition and re-roofing projects, and an experienced roofer will know where to source them. Tell your roofer the age of the property, the colour and texture of the existing slate, and whether it is thick-bed or thin. Taking a photograph of the existing roof before any repair work starts gives your roofer a reference point when sourcing materials.
Natural slate is a low-maintenance material but not a no-maintenance one. Three habits are the whole of it.
Look at It Once a Year
From ground level with binoculars. You are looking for lifted or slipped slates, missing or cracked ridge pointing, and significant moss or lichen growth.
Annual, from the ground
Treat Moss, Do Not Blast It
Most slate roofs in Ireland develop moss over time. A biocide treatment is effective and far less damaging than pressure washing, which can crack or dislodge slates.
Biocide, not a power hose
Check the Lead Every Five Years
Flashings at chimneys, valleys and skylights should be checked every five to ten years. Lead hardens and develops hairline cracks over decades, and repointing it is a small job that prevents significant internal water damage.
Chimneys, valleys, skylights
A well-maintained slate roof should provide 80 years or more of service with no more than occasional minor repairs and flashing attention.
Is natural slate worth the extra cost over synthetic?
On lifespan alone, usually yes. Natural slate lasts 80 to 150 years and there are Victorian roofs across Dublin, Limerick and Cork still covered in their original slates, while synthetic slate lasts 25 to 50 years depending on the product. Synthetic also tends to look uniform and can appear slightly plastic compared to the varied texture of natural stone. For period properties, conservation areas or any building in a historic streetscape, natural slate is usually the only appropriate choice, and conservation officers will often specify it for protected structures.
What does a slate roof cost per square metre in Ireland?
As a 2026 guide, natural Spanish slate runs from about EUR 60 per square metre installed, which covers stripping the existing covering, new breathable felt underlay, treated battens and laying the new slate. Irish Killaloe or Welsh slate starts nearer EUR 90 per square metre and rises with supply. Scaffold is usually a separate line at EUR 800 to 2,000, so confirm whether it is inside the quote or outside it before you compare two prices.
What is Killaloe slate and can I still get it?
Killaloe slate is quarried near Lough Derg in County Clare and is one of the finest roofing slates produced anywhere in Ireland or Britain. It is a dense, dark blue-black stone with excellent frost resistance, well suited to the Irish climate, and Georgian and Victorian buildings throughout Ireland were originally roofed in it. It is still available, but supply is limited and prices are at a premium compared with imported slate. Ask your roofer to source it from a reputable Irish supplier and request a sample before ordering.
How do I match new slates to an old roof?
Colour, texture and thickness all vary between slate types, quarries and even different batches from the same quarry, so a patch repair using the wrong slate looks obviously wrong. Salvaged slates from reclamation yards are often the best match for older roofs, and an experienced roofer will know where to source them. Tell the roofer the age of the property, the colour and texture of the existing slate and whether it is thick-bed or thin, and photograph the roof before any work starts so there is a reference point.
When should I re-slate rather than patch?
If more than 30 per cent of the slates need replacing it is worth considering a full re-slate. Mixing large areas of old and new slate creates a patchy appearance, and the old slates left in place are likely to need replacement within a few years anyway. A patch repair makes sense when the failures are grouped in one area, a match can be sourced, and the battens and underlay beneath are still sound.
How much maintenance does a slate roof need?
Natural slate is a low-maintenance material but not a no-maintenance one. Inspect it from ground level once a year with binoculars for lifted or slipped slates, cracked ridge pointing and heavy moss. Treat moss with a biocide rather than pressure washing, which can crack or dislodge slates. Check lead flashings at chimneys, valleys and skylights every five to ten years, because lead hardens and develops hairline cracks over decades. Looked after that way, a slate roof should give 80 years or more with only occasional minor repairs.
Slate is a trade inside a trade. Sourcing a match, setting the right gauge and dressing the lead properly are the difference between a roof that lasts a century and one that is patchy in five years.