What is a slate tingle?

Picture the bottom edge of a slate. On a tingle repair there is a thin tongue of metal curling up from underneath and lying across that edge. The tongue is the tingle. Its other end is nailed to the batten, the timber strip the slates hang from, and the bend in the middle grips the slate so it cannot slide down. From inside the loft you will not see it at all, because the whole arrangement sits on the outer face of the roof, under the slate above and over the slate below.

The material is soft enough to shape by hand on the roof. Lead is the traditional choice, and copper is also used. Roofers cut the strip narrow, folded back on itself so it springs against the slate, then dressed flat so it neither collects rain nor stands proud for the wind to lift. Made properly, it is hard to see from the pavement. Made carelessly, it is a loose tab, and the slate creeps out of line before long.

A slate is normally held by nails driven near its top, through holes made at the quarry or punched by the slater. Each course then overlaps the nails of the one below, so they are hidden. That is the strength of the design, and also the difficulty of repair: once the courses above are in place, you cannot hammer a new nail where it needs to go without lifting a whole group of slates.

The tingle solves that. The replacement slate is slid up under the course above until it sits in line, and the tingle is nailed to the batten below it and bent over the tail. No access to the hidden nail position is needed. That makes it the usual answer for one broken, missing or slipped slate when its neighbours are firmly held. Our page on replacing a cracked slate walks through the full sequence, with the tingle as its last step.

One tingle on a slope tells you somebody mended a slate once. A dozen, spread across the slope, tells you something else: the original fixings are giving up. Nails in old slate roofs corrode where they pass through the slate, the slate loosens, and eventually it slips. The trade calls this nail sickness, and our page on nail sickness explains the mechanism.

Each repair gets a tingle because that is the quick, tidy fix, but the pattern matters more than any single strip. If the slates around a tingle are already sliding, the next gale will find the next weak one. That is the point where a plain verdict does more good than another patch: some roofs are best repaired in sections, some need a patch for now with a date set for re-slating, and a few are past help. We say which you have, and show the roof to prove it.

The tingle is not the only option. Slates can also be held with stainless hooks or clips that catch the tail, and a modern re-slate may use them throughout. Cupa Pizarras advises against hook fixings below a 25 degree pitch, which leaves nails for the lower roofs. Our comparison of slate hooks against nails sets out which suits which roof.

BSI records that BS 5534's recommendations may be a poor match for re-slating some old roofs, especially those built of traditional or reclaimed slate. For us that means an older roof is judged on its condition and not by ticking boxes. A Victorian terrace with soft, thin slates needs a lighter touch than a newer roof with uniform ones, and we pick the fixing to suit the slate in front of us. A tingle remains a sensible repair on such a roof, because it avoids disturbing slates that are bedded and still sound. On a roof being fully stripped, we would nail or hook every slate properly and not rely on tingles at all.

Slate breaks under a boot. Someone who strolls across a slope can crack several slates and start fresh leaks while mending one. So we work off a ladder laid along the roof, or off scaffold, and spread our weight over boards. Our page on walking on a slate roof explains the reasons.

If a slipped slate is letting water in today, tell your insurer before you claim, snap the slope from your garden, and keep every receipt for temporary work. Which? gives that advice, and cautions that a neglected roof letting rain in may be written off by insurers as simple ageing. A leak gets made safe on our first visit. Fitting the tingle is quick. Checking the slates around it takes longer, and that check tells you whether this is a one-off or the first of many. It is also the moment we look at the slate roofing as a whole, because a single repair is only the visible part of the question. Slate roofing covers the full range of work.