Roofs on Coalville’s Miners’ Terraces: What Goes Wrong and How to Fix It

On the miners’ terraces of Hugglescote, Ellistown and central Coalville, the slate usually outlives everything holding it up. These roofs went on as Welsh slate double-nailed to sawn softwood battens, with no underlay at all and lime torching packed underneath instead — so after 120 winters it is the iron nails, the torching and the valley boards that fail, not the slate. A terrace can shed slates from six different courses and still have a covering worth reclaiming, so the repair-or-re-roof decision turns on the fixings, not on the ceiling stain.

Why is so much of Coalville roofed to the same recipe?

Because the town went up in a rush, and the railway that created it also brought in the slate. William Stenson sank a shaft beside what is now Hermitage Road in 1824, on a road then called Long Lane; George and Robert Stephenson began Snibston Colliery in 1831; and the Leicester and Swannington Railway reached Long Lane in April 1833.

The eastern pits came a generation later — Ellistown Colliery was commenced in 1874 by Joseph Joel Ellis, whose name the village carries, and South Leicester Colliery was sunk in 1876. Housing chased the shafts, and the streets that filled in between the 1870s and the 1900s went up quickly, by the row, to one specification. Snibston’s last coal came up in December 1983 and Bagworth, the coalfield’s last pit, closed in 1991; the roofs are mostly still on their original nails.

How was a miners’ terrace roof actually built?

• Welsh slate, double-nailed. Two nails per slate, commonly iron, into sawn softwood battens. Copper and stainless fixings are standard now; they are not what went on in 1890.
• No underlay. Lift a slate on an untouched roof and there is nothing behind it but battens and daylight.
• Lime torching instead. Haired lime mortar buttered onto the underside of the slates between the battens, to stop them lifting and keep wind-driven rain and snow out. It was the underlay.
• Lead at every junction. Soakers and stepped flashings at the party-wall stack; a lead-lined valley or secret gutter where the back addition meets the main roof.
• A stack standing on the party wall, often carrying flues from both houses.
• One gutter for the row, running unbroken from end to end.
• A rear back addition at a shallower pitch than the front slope — the wing that took the scullery, and the part that causes most trouble.

What fails first after 120 winters?

What you see	What has happened	What it means
Slates slipping from several different courses	Nail sickness — the iron nails have corroded through	The whole slope is on the same clock
Slates flaking into thin leaves	Delamination — frost in the slate’s bedding planes	Replace singly, or re-cover if widespread
Grit in the insulation, draughts in the roof space	The lime torching has perished and dropped off	Underlay replaces it at re-roof; it cannot go back
A stain along the back-addition junction	Rotten valley boards, or a corroded secret gutter	Renew the boards, re-line in code-correct lead
Damp on an upstairs chimney breast	Open joints, perished flashings, cracked flaunching	Repoint, renew the flaunching, re-flash the stack
Water sheeting over the gutter three doors along	One blockage backing up a continuous run	Clear it, re-set the fall, replace sagged lengths

Nail sickness is progressive rather than local: every fixing on a slope went in the same week from the same keg, so once one course lets go the others follow. A shared gutter is a communal fault — a blockage above one house sends water down another family’s wall.

Repair or re-roof: where does the line fall?

A useful test is to count courses, not slates. One or two losses in the same patch is damage; losses at different heights across the slope is failed nailing.

Repair is right while the covering is sound and the fault is local — a slipped slate, a split valley lining, a perished flashing. Roof repairs of that kind commonly run £150–£350, rising to £350–£900+ once scaffolding, ridge work or new flashings come into it. Have the valley boards probed while someone is up there: a slate bedded back over soft boarding moves again by next winter.

A full re-roof is the better spend once the nailing has gone across the slope, the battens are soft, or you are three repairs in and still catching drips. Our Coalville roof cost guide puts a typical semi at £4,000–£6,500; a mid-terrace is a smaller area but pays for tighter scaffolding and party-wall detail, so it does not scale down — [TODO: confirm] a terrace-specific band. Allow 5–10 working days on site.

What has to be squared with the neighbours first?

The stack. A chimney standing on the party wall belongs to both houses, and work to it can fall under the Party Wall etc. Act 1996. It is also a poor repair done by halves, since joints, flaunching and lead weather together — chimney repointing and re-flashing is better done once, with the cost shared by agreement.

The gutter. Where one gutter serves the row, taking down a single length means opening the run and re-setting the fall, so neighbours are usually glad to have the whole run cleared while access is up. Say in advance, too, that new lead soakers and flashings will be dressed into next door’s slates at the party wall — normal work, but easier explained than discovered.

What changes once a breathable membrane goes on?

The roof stops leaking air, which matters more than it sounds. An old torched roof ventilated itself through a thousand small gaps; a membrane makes the roof space markedly tighter, so warm, moist air rising from the house condenses underneath and drips into the insulation unless it is given a route out.

That route is specified alongside the covering: an air path equivalent to a continuous 10 mm gap along both eaves, through vented soffits or eaves trays, plus high-level ventilation at the ridge where the design requires it.

Will the street still look like a street?

A row reads as one roof from the pavement, so slate size, course spacing and the ridge line matter more than exact shade. Keep the original gauge and the eye sees continuity; change it and a step appears at the party wall for the length of the terrace. Where much of the old slate still rings true it is worth reclaiming onto the street elevation, with new slate to the rear.

Frequently asked questions

What is nail sickness, and can it be repaired?

Nail sickness is the point at which the iron nails holding the slates have corroded through. The slate is often still sound, but nothing is holding it, so slates slide out of several different courses. Isolated losses can be refixed; once they are scattered, the fixings have failed as a batch.

Can one house in a terrace be re-roofed on its own?

Yes. A mid-terrace roof is stripped and re-covered up to the party walls, with new lead soakers and flashings dressed into the neighbouring slates so the junction stays watertight. The awkward parts are the scaffolding, a shared chimney stack, and any gutter running unbroken along the row.

Do I need my neighbour’s permission to work on a shared chimney stack?

A stack built on the party wall is a shared structure, so work to it can fall under the Party Wall etc. Act 1996 and may require written notice to the adjoining owner. Repointing half a stack is also poor value, because joints, flaunching and lead weather as one.

Why does a re-roofed terrace need extra loft ventilation?

Because the new roof is far tighter than the old one. A torched slate roof leaked air constantly, so the loft was ventilated whether anyone intended it or not. Once a membrane and a modern covering replace that, moist air needs a designed way out: an air path equivalent to a continuous 10 mm gap at both eaves, plus ridge ventilation.

Will new slate look out of place next to the neighbours’ roofs?

Not if the slate size and the course spacing are matched. Reclaimed Welsh slate in the original size blends in immediately, and good new slate weathers in over a few winters. What looks wrong is a change of material or gauge, because either shows as a step in the line of the row.

If slates are moving on your terrace and you want a straight answer on repair or re-roof, we will look at the slope, the loft and the valley boards — call Armour Shield on 07366 472857 for a free, no-obligation quote.