One of the most common calls we get is from homeowners who've had slates replaced repeatedly over the years and are still seeing new ones slip. This pattern — slates failing across the whole roof rather than in isolated spots — is almost always nail failure, not slate failure.
Here's what's happening. The iron or steel nails used on virtually all Dublin slate roofs built before the 1960s corrode progressively within the slate hole until they can no longer carry the weight of the slate above. The slates themselves are often perfectly sound. The problem is entirely in the fixings.
This is called nail sickness. Replacing individual slates on a nail-sick roof won't solve it — new slates fixed through the same corroded nails will fail within a few years, and the cycle continues.
The correct response is a full re-slate — stripping the covering, replacing felt and battens, and re-laying with stainless steel fixings. Where the original slates are in good condition, a significant proportion can be salvaged and reused, reducing cost and preserving the character of the original roof.
Sean assesses every slate roof for nail sickness at the inspection stage and gives a straight answer about whether repair is viable or whether re-slating is the only practical long-term solution.
No jargon. No hard sell. Just a clear process from your first call to a weatherproof roof.
The most common slate repair call — single or multiple slates that have slipped, cracked, or broken through storm damage, impact, or localised nail failure. We replace like-for-like using matched natural or fibre cement slate, fixed correctly at the right gauge for the roof pitch. Surrounding slates are checked for security as part of every individual replacement job.
Where multiple slates across the roof face are slipping or have slipped — indicating nail failure rather than isolated damage — we assess the full extent of the problem and advise on whether targeted refixing or full re-slating is the appropriate response.
When a slate roof has reached the end of its serviceable life — through nail sickness, widespread felt failure, or simply the age of the covering — we strip back to the rafters, replace felt and battens, and re-lay to a high standard using stainless steel fixings. Where the original slates are sound, we salvage and reuse them where possible.
High winds lift slates that are already borderline on nail security and crack or dislodge slates through impact from debris. Post-storm repairs are carried out promptly to prevent water ingress from open areas of the roof deck.
Ridge tiles on slate roofs are bedded in mortar that deteriorates over time — cracking, lifting, and eventually allowing water into the ridge junction. We re-bed and repoint ridge tiles using the correct mortar specification for the age of the property, and reset hip tiles on complex slate roof profiles.
Where the underlay beneath the slates has failed — visible in the attic as daylight showing through, or as water tracking down onto the insulation — we address the felt and batten condition as part of any major repair or re-slate, not as an afterthought.
The valleys and flashings on a slate roof are as important as the slate covering itself. We replace and re-dress lead valleys and flashings on slate roofs as needed — using the correct lead code and dressing it properly to shed water rather than hold it.
Not all slate roofs in Dublin use natural stone. Fibre cement slates — manufactured composite products sold under brand names like Eternit, Cembrit, and Marley — are widely used on Dublin's post-1970s housing stock and require the same care in matching and fixing as natural slate. We carry a range of fibre cement profiles for repair work.
Real Results From Home-Owners in Dublin!
Dublin has one of the most varied and historically significant housing stocks in Ireland — and slate is woven through all of it, from the oldest to the relatively recent.
Victorian & Edwardian Terraces (pre-1920) The red-brick terraced streets of Rathmines, Ranelagh, Drumcondra, Clontarf, Phibsborough, and the south inner city were built almost universally with natural Welsh slate — blue-grey Penrhyn or similar. Many are still on their original covering, now 100 years old or more. These roofs need experienced, sympathetic repair work — correct mortar, correct matching, correct fixing — not a crew that treats them the same as a 1980s semi-detached.
Inter-War & 1950s Properties (1920–1960) Dublin's expansion through Crumlin, Drimnagh, Cabra, and the early suburbs was built predominantly with natural slate, though quality and provenance varies more than in the Victorian stock. Nail sickness is increasingly prevalent on roofs in this age bracket — these properties are at the age where the original iron fixings are at or past the end of their reliable life.
1960s–1980s Suburban Stock Dublin's post-war suburban expansion — Tallaght, Blanchardstown, Clondalkin, Swords, Rathfarnham — used a mixture of concrete tile and fibre cement slate. Properties in this range with slate covering are typically on fibre cement rather than natural stone, and like-for-like fibre cement repair is the correct approach.
Period Detached Properties Larger Victorian and Edwardian detached properties in areas like Rathgar, Terenure, Stillorgan, and the coastal villages often have complex roof profiles — multiple hips, valleys, dormers, and chimney stacks — that require genuine slate roofing experience to repair correctly. These are the jobs that separate contractors who genuinely know slate from those who do it occasionally.
DJ Roofing Dublin carries out slate roof repairs and re-slating throughout Dublin City and County — every area, north to south.
North Dublin: Swords, Malahide, Howth, Clontarf, Drumcondra, Glasnevin, Finglas, Blanchardstown, Castleknock, Santry, Raheny, Artane, Baldoyle
South Dublin: Rathfarnham, Terenure, Templeogue, Dundrum, Stillorgan, Blackrock, Dún Laoghaire, Dalkey, Killiney, Churchtown, Rathmines, Ranelagh, Sandymount
West Dublin: Lucan, Clondalkin, Tallaght, Palmerstown, Rathcoole, Newcastle, Saggart, Adamstown
Dublin City Centre: D1, D2, D4, D6, D7, D8, D12
Not sure if we cover your area? Call us — we almost certainly do.
The key distinction is whether you're seeing isolated damage — individual slates cracked or missing after a storm — or widespread slippage across the roof face year after year. Isolated damage is repaired. Widespread slippage that keeps recurring despite repairs is almost always nail sickness — and that means re-slating is the only practical long-term solution. Sean will give you a straight answer at the inspection stage.
In most cases, yes — to a very close match. We source natural slate carefully for repair work on period properties and carry a range of fibre cement profiles for matching on suburban stock. On very old roofs where the original slate may be reclaimed or from a discontinued quarry, we'll be honest about the degree of match achievable before the work starts.
Natural slate correctly fixed lasts 80 to 100 years — many of Dublin's Victorian terraces are still on their original covering. The limiting factor is almost always the fixings rather than the slate itself. Fibre cement slate carries manufacturer guarantees of 30 to 50 years. The roof structure beneath — felt, battens, timbers — typically needs attention before the slate itself fails.
Nail sickness is the progressive corrosion of the iron or steel nails fixing slates on older roofs, to the point where the nails can no longer carry the weight of the slate. It presents as widespread slippage — multiple slates shifting out of position across the roof face, year after year, without obvious damage to the slates themselves. It's assessed at inspection by checking accessible nail condition. If your roof has had multiple slates replaced repeatedly over several years, it's worth having the nail condition properly assessed.
Replacing a handful of individual slates is a minor repair. A full re-slate on a large Dublin detached property in natural Welsh slate is a significant investment. The range in between depends on the extent of the slippage, the material used, and whether additional work — ridges, flashings, valleys — is included. We always inspect first and provide a full written quote — no estimates over the phone that change when we're on the roof.
Yes. Dublin has a significant stock of protected structures and properties within Architectural Conservation Areas — particularly in the inner suburbs and city centre. We understand the requirements around like-for-like repair and the use of appropriate traditional materials on protected buildings, and we work sympathetically on period properties throughout the city.
Yes — and it's often well worth doing. On a nail-sick roof where the slates themselves are in good condition, a significant proportion of the original covering can be carefully removed, checked, and relaid. This reduces material cost and preserves the character of the original roof — particularly valuable on Victorian and Edwardian properties where the original Penrhyn slate has a patina and character that no new slate can replicate.
Whether you've had a few slates slip after a storm, you're seeing the same sections move year after year, or you simply don't know what condition your slate roof is in — a proper inspection is the right starting point.
Call DJ Roofing Dublin for a free slate roof inspection across Dublin City and County. Straight assessment, written quote, no call-out fee, no pressure.
DJ Roofing offers a full range of roofing services for homeowners and landlords throughout Dublin.
DJ Roofing Dublin provides professional roofing services to homeowners and commercial property owners throughout Dublin City and County. Our services include roof repairs, roof replacement, flat roof repairs, chimney repairs, slate roof repairs, fascia and soffit replacement, gutter repairs, skylight repairs, and emergency roofing.
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