Natural Slate Re-Fix on a Kinsale Period Terrace: A4 Marine-Grade Job Log

What is nail sickness, and why does Kinsale get it early?

Nail sickness is the slow corrosion of the nails that pin each slate to the battens. The slates themselves, good natural slate, can outlast two sets of nails. What the homeowner sees is a slate on the path after a gale, then another a month later, then a patch of daylight in the attic. Each one looks like a small repair. The pattern is the diagnosis: the nails across the whole elevation are the same age and the same material, and they are all failing together.

Kinsale gets it early because the harbour and Compass Hill take marine air all year. Salt works into every fixing on the roof. The same failure pattern shows up across the coastal towns, and our coastal Cork salt erosion post covers the Crosshaven semi-D version of it, where nail failure on newer stock runs on an 8-12 year cycle. This Kinsale job is different stock: period natural slate on a terrace, not fibre-cement on an estate, and the subject here is slate, not lead. The principle is the same though. Within a few miles of the coast, fixing spec is not a detail, it is the job.

What did we find on the Kinsale terrace?

The call came in as "another two slates down". The house is a period terrace above the harbour, natural slate throughout, diminishing courses, the kind of roof that gives the street its look. The homeowner had already paid for two ladder repairs in two winters. Each was honest work, but each was treating one symptom of an elevation-wide failure.

Up close, the picture was classic. Slate heads lifting across the lower courses. Corroded nail stubs visible where slates had already gone. A scatter of tar patches from older repairs, none of them holding. The underlay, what was left of an old bituminous felt, was perished at the laps. The slates themselves were the good news: thick, dense, mostly sound. This was a roof worth re-fixing, not replacing.

The decision rule is simple. If the slate is sound, you do not strip a period roof off and bin it. You take it down carefully, keep everything that passes inspection, and put it back on fixings that will outlast the next fifty years.

How does a conservation-aware re-fix actually run?

Scaffold first. A whole-elevation strip on a terraced period house is not ladder work, full stop. Edge protection goes up, and on a harbour-side Kinsale street that means a tighter footprint and smaller load-ins than an estate job. Once the scaffold is up, the method is slow on purpose:

1. Strip in course order. Slates come off from the ridge down, and every course is numbered as it lands. The diminishing courses on a period roof are sized to their position, so a slate from course four does not fit course twelve.
2. Grade every slate. Sound slate goes to the keep stack. Cracked, delaminated or soft slate goes to the skip. On this job roughly seven in ten passed.
3. Battens and underlay. Rotted battens are replaced, breathable underlay goes on, and new battens are set to the original gauge so the courses run true.
4. Re-lay on marine-grade fixings. The same slates go back in the same courses, each one fixed with A4 stainless or 65mm copper clout nails. Holes are re-drilled where the old nail hole has opened up.
5. Make good the details. Ridge, verges and abutments checked while the scaffold is there. Coastal flashing spec in Kinsale is code 5 or code 6, never reused code 4.

Two to three working days on the roof once the scaffold was up, weather depending. Slate work stops in the wet because you cannot leave a stripped elevation open overnight.

What does slate repair cost in 2026 Cork?

The small end of slate work prices like any other repair: time on the roof, materials, and access. Prices below are from our Cork job logs, VAT included at the 13.5% rate that applies to qualifying roofing work.

There is no honest fixed band for a whole-elevation re-fix on a period terrace. Salvage rate, batten condition, underlay area, access and elevation size all move the number, and any roofer who prices one from the pavement is guessing. What we commit to is a written scope with the salvage expectation stated, so the price is fixed before a single slate comes off.

Materials stay cheap relative to labour even on slate work. The copper clouts for an entire elevation cost less than the scaffold delivery. The money is in the days on the roof and the care in the strip. That is why a re-fix only makes sense on sound slate: you are paying for skilled time, and it is wasted on a roof covering that has already failed.

Why not just keep paying for ladder repairs?

Because nail sickness does not repair one slate at a time. The homeowner on this job had already paid for two single-slate visits. Each was €150-€220 of honest work, and neither touched the underlying failure. When slates keep coming off the same elevation, the next ten repairs are already scheduled; you just do not know the dates yet.

The tipping point we use: when a second slate comes off the same elevation inside a year, stop repairing and start planning the re-fix. You will spend the re-fix money either way, in €150 instalments with tar patches, or once, properly, with the salvage kept and the courses true.

What does the re-fix come with in writing?

Every job over €100 carries our 20-year written workmanship guarantee, issued as a PDF certificate and transferable with the property if you sell. On a period terrace that matters at sale time: a buyer's surveyor reading "re-fixed on marine-grade fixings, guarantee to 2046" asks fewer questions than one reading "patch repairs, various dates".

We carry €6,500,000 public liability through AXA (Tradesman Policy 12/28/150946921), the crew is Safe Pass certified and fall-arrest trained, and period terrace work is scaffolded, not laddered. If your terrace is showing the same pattern, slipped slates repeating on one elevation, start with the Kinsale roofing and period property page or send photos through the contact form. We cover Kinsale, the harbour streets and Compass Hill within five working days for non-urgent surveys.