What Is Nail Sickness?The Roof Problem Affecting Thousands of Shropshire Homes

What Is Nail Sickness?

Nail sickness is the progressive failure of the metal fixings that hold roof tiles in place. On the vast majority of properties built before 1980, roof tiles were fixed using cut galvanised nails — steel nails with a thin zinc coating. Over 40 to 60 years, those nails corrode. When they fail, tiles are held in place by gravity and friction alone. The first strong wind lifts them off.

It is the most common structural roof problem across Shropshire's post-war housing stock, and the most frequently misdiagnosed. Homeowners call for a tile repair. A roofer puts the tile back. Six months later, a different tile slips. The cycle repeats indefinitely — because no one has addressed the actual cause.

Galvanised cut nails used on roofs built between 1950 and 1980 have a design life of 40–60 years — meaning the majority of Shropshire's post-war concrete tile roofs are now at or past the point of nail failure (source: NFRC technical guidance, 2023).

Why Is It So Common in Shropshire?

Shropshire's post-war housing boom produced tens of thousands of homes in the 1950s, 1960s and 1970s. Shrewsbury's northern suburbs — Harlescott, Sundorne and Ditherington — were largely built in this period. Telford's new town estates in Dawley, Madeley, Stirchley, Brookside and Hollinswood followed through the 1960s and 1970s. The concrete interlocking tiles on these properties were fixed with the same cut galvanised nails used across the UK at the time.

Those nails are now 45 to 75 years old. The design life of a galvanised cut nail in a roofing application is approximately 40 to 50 years. Do the maths.

How to Spot Nail Sickness From the Ground

You don't need to get on the roof to identify the warning signs. Stand back and look at each pitch:

A single slipped tile after a major storm event is not necessarily nail sickness — it could be impact damage or an isolated fixing failure. But if you've had two or more tiles slip in different locations over the past 12 months, nail sickness is the overwhelming probability.

The Two Options: Re-Nail or Replace

Once nail sickness is diagnosed across a significant area of the roof, there are two correct responses:

Option 1: Full nail-and-re-fix

Every tile on the affected pitch is removed, inspected for damage, and re-laid using stainless steel ring shank nails — which will not corrode for 80 to 100 years. Damaged tiles are replaced. The underlay is inspected and replaced if deteriorated. This is the correct approach where the tiles themselves are in acceptable condition and the roof structure is sound.

Option 2: Full roof replacement

Where tiles are surface-eroded, brittle or in poor condition — or where the underlay has deteriorated beyond use — a full replacement using new concrete or clay tile is the better investment. The additional cost over a re-nail is relatively modest when the scaffold is already in place, and the result is a 30 to 50 year roof with a full 10-year workmanship guarantee.

Which Shrewsbury and Shropshire Areas Are Most Affected?

The worst-affected areas in our coverage are those developed predominantly in the 1960s and 1970s:

• Shrewsbury: Harlescott, Sundorne, Ditherington, parts of Bayston Hill
• Telford: Dawley, Madeley, Stirchley, Brookside, Hollinswood, Sutton Hill, Woodside
• Oswestry: The 1970s estates on the town's eastern fringe
• Whitchurch: Sherrymill Hill and Yardington development

If your property is in one of these areas and was built between 1955 and 1982, a free roof survey is a sensible investment before the problem becomes urgent.

Frequently Asked Questions

Choosing the Right Contractor for This Type of Work

The most effective protection when commissioning roofing work of any type is insisting on a written, itemised quote from a contractor who can demonstrate both current insurance and verifiable trading history. A contractor unwilling to provide either — or who provides a quote that is too vague to allow comparison with others — should be treated with caution regardless of the price.

The standards that apply to roofing work in Shrewsbury are not exceptional. Physical survey before quoting, written fixed-price specification, stainless fixings, breathable underlay, correct mortar for the property era, and a written workmanship guarantee are normal expectations from a legitimate contractor. If a quote does not include these elements, ask why before agreeing.

How to Get an Accurate Quote for This Type of Work

The most common source of post-job dissatisfaction in roofing is a mismatch between what the homeowner expected and what was actually agreed in the quote. The gap usually exists because the quote was not specific enough to define expectations on both sides. Getting an accurate, reliable quote requires the same steps regardless of the type of roofing work involved.

First, the contractor must physically access the roof before quoting. A quote based on a description of the problem, ground-level inspection or photographs is not a reliable fixed price — it is an estimate that will be revised once the work starts and the actual condition is visible. Insist on a physical survey as the basis for any written quote.

Second, the quote must specify materials. 'Quality materials' is not a specification. The tile manufacturer, profile, colour and product guarantee should be named. The underlay type should be specified as breathable, not generic felt. Lead work should specify the code weight for each application. Without this detail, the contractor can substitute cheaper alternatives without violating the terms of the quote.

Third, the quote should identify what is excluded as well as what is included. Access, waste disposal and VAT are the most frequent sources of unexpected additional cost at completion. A quote that includes scaffold erection and removal, waste disposal to a licensed tip, and shows VAT as a separate line item is transparent and trustworthy. A quote that omits these elements and adds them at invoice stage is not.