Nail sickness is the corrosion of galvanised tile-fixing nails, common on Worthing roofs built between 1930 and 1980. It cannot be seen from the ground — tiles sit flat until a gale lifts them in sections. A specialist inspection with direct roof access is the only reliable way to assess it. Call 01903 905 128.
Nail sickness is the most common roofing problem we diagnose on Worthing's 1930s–1970s housing stock. It's invisible from the ground, rarely flagged in a standard survey, and when it fails, it fails suddenly. Here's what you need to know.
What Is Nail Sickness?
Every roof tile or slate is fixed to the roof batten beneath it using a nail — typically one per tile, driven through a preformed hole near the top of the tile. On roofs built before roughly 1990, those nails were usually made from galvanised steel: steel wire coated in a thin layer of zinc to prevent rusting.
Over time, that zinc coating degrades. As it does, the steel beneath begins to rust. The rust is initially surface-level and doesn't affect the nail's structural integrity — but as it progresses, the nail cross-section reduces. Eventually, the corroded nail can no longer hold the tile against wind uplift. The tile is mechanically unfixed — it's sitting loose on the roof, held only by gravity and the pressure of adjacent tiles.
That condition is nail sickness. And it's endemic across Worthing's interwar housing stock.
British Standard BS 5534 now requires corrosion-resistant fixings such as stainless steel, precisely because the galvanised nails specified on pre-1980 roofs corrode long before the tiles fail.
Source: British Standard BS 5534
Why Is Worthing Particularly Affected?
Three factors make nail sickness progress faster on Worthing properties than equivalent homes inland:
1. Age of the Housing Stock
The large residential estates of Goring-by-Sea, West Worthing and Durrington were built predominantly between 1930 and 1960. That's 65–95 years of nail life. Galvanised nails have a typical effective lifespan of 40–60 years before the zinc coating fails. On these properties, nail sickness is not a future risk — it's the present reality.
2. Salt Air Chloride Attack
Chloride ions in sea air are aggressive to galvanised coatings. Salt particles carried inland from the English Channel react with the zinc, forming zinc chloride compounds that are soluble and wash away — stripping the protective coating faster than would occur in a neutral inland environment. Properties south of the A259 in Goring and West Worthing see this effect most strongly.
3. Thermal Cycling
South-facing roof slopes in Worthing experience significant temperature swings between summer and winter, and between day and night. Each thermal cycle causes microscopic movement between the tile and the nail. Over 70+ years, this cumulative micro-movement fatigue further weakens the nail-to-tile connection.
Signs of Nail Sickness — What to Look For
From the Ground (Limited)
Nail sickness is notoriously difficult to identify from the ground, which is why it's so often missed. However, there are some observable indicators:
- Slipped or displaced tiles — tiles that have moved out of alignment, particularly after a period of wind. Nail-sick tiles shift progressively as wind uplift moves them incrementally upward.
- Irregular tile surface — areas where tiles appear to be sitting at a slightly different angle to their neighbours, suggesting they've moved from their original position.
- Tiles after storms — if tiles regularly come off after storms that don't affect neighbouring properties, loose fixings are almost certainly the cause.
- Rust staining — occasionally, corroding nails will cause rust staining to appear on the tile surface below the fixing point. Rare, but diagnostic.
On Inspection (Definitive)
The only reliable way to assess nail sickness is direct access to the roof — physically checking tile fixing condition across multiple areas of the roof slope. What a trained roofer looks for:
- Lift test — applying upward pressure to the head of individual tiles to test fixing resistance
- Nail extraction — in suspect areas, removing a nail to examine its cross-section and remaining zinc coating
- Pattern mapping — identifying which elevations and roof zones show the highest incidence of loose tiles
- Underlay condition — inspecting whether the felt underlay beneath loosened tiles has been compromised
When more than approximately 30% of tiles across a roof slope show evidence of nail sickness, full replacement becomes more economic than targeted repairs. Replacing individual nails on a 70-year-old concrete tile roof requires stripping and re-fixing at the same cost as full re-roofing but without the guarantee, new felt and batten that a complete replacement provides. This is a judgement that requires an experienced roofer, not a general surveyor.
Nail Sickness in Slate Roofs
The same process applies to Welsh slate roofs, which are common on the Victorian and Edwardian terrace stock in Broadwater and the town centre. Original Victorian roofing used iron or wrought iron nails, which rust more aggressively than later galvanised nails. On properties built before 1900, nail sickness in slate is not just possible — it's virtually certain unless the roof has been re-fixed at some point.
Slate nail sickness manifests slightly differently: rather than entire tiles shifting, individual slates slip down the roof slope until they're held by the remaining good nail on the opposite side — creating a characteristic "smile" pattern visible from the ground.
What Happens If Nail Sickness Is Ignored?
In the short term: nothing visible. Tiles sit loose but remain in place in calm weather. The first time a significant south-westerly gale arrives — and they arrive in Worthing regularly between October and March — the loose tiles lift. Sometimes individually, sometimes in sections. Once airborne, a concrete interlocking tile weighs 4–5kg and causes serious damage to whatever it lands on.
In the medium term: water ingress. Displaced tiles leave gaps in the tile course. Water tracks through gaps to the underlay, which on a 70-year-old roof is almost certainly original and nearing the end of its effective life. Saturated underlay leads to rot in the timber batten and rafter below — which adds structural repair cost to the roofing bill.
What's the Fix?
For isolated nail sickness on a roof where the majority of tiles are otherwise sound, targeted re-nailing using ring-shank stainless steel nails can extend the roof's useful life. This is appropriate where less than 20–25% of tiles are affected.
Where nail sickness is widespread — which it typically is on Worthing's 70–90 year old stock — the correct answer is full replacement. Strip the tile, replace the felt underlay, replace the batten, relay new tile using stainless steel fixings throughout. We replace Worthing's concrete tile with modern clay interlocking, which is more durable, more coastal-resistant, and carries a far longer design lifespan than a like-for-like concrete replacement.
If you have a property in Goring-by-Sea, West Worthing or Durrington with an original concrete tile roof, or a Victorian terrace in Broadwater with original Welsh slate, call us for a nail sickness assessment. We inspect the full roof, test fixing condition across multiple zones, and give you an honest written report. Call 01903 905 128.
Frequently Asked Questions
Nail sickness is the corrosion of galvanised steel tile-fixing nails over time. It is particularly common in Worthing because the 1930s–1960s housing stock in Goring-by-Sea, West Worthing and Durrington has roofs 65–90 years old — well past the design life of galvanised fixings — and coastal salt air accelerates the corrosion.
No. Nail-sick tiles look normal from ground level and sit flat until a significant gale provides enough uplift to displace them. A specialist inspection with direct roof access is the only reliable assessment method.
Tiles remain in place in calm conditions but can lift in sections during south-westerly gales. Once displaced, the exposed felt underlay — which on a 1930s property is likely also original and near end of life — allows rapid water ingress. Structural timber rot follows within one to two winters.
If less than 20% of tiles are affected, targeted re-nailing using stainless steel fixings costs £600–£1,800. If nail sickness is widespread, full replacement is more economic at £5,500–£9,000 for a standard 3-bed semi. We assess honestly at inspection. Call 01903 905 128.
About the author
Worthing Roofing Experts — local roofing specialists serving Worthing and the West Sussex coast since 2003. NFRC registered, fully insured, 10-year workmanship guarantee on all work. Call 01903 905 128 for a free, no-obligation quote.
Last reviewed: 20 July 2026 by Worthing Roofing Experts.