Slipped and broken roof tiles

Why tiles and slates slip

A concrete or clay tile hangs from a timber batten by nibs on its back, and on many roofs some courses are also nailed. A natural slate relies entirely on its nails, normally two per slate. If either the fixing or the batten gives up, gravity does the rest and the piece slides down until it catches on the course below or falls into the gutter.

A gap in a row of tiles, a piece sitting lower than its neighbours, or broken fragments on the drive are the usual first clues.

Storm damage

Strong gusts create suction on the leeward side of a roof. Tiles at the verges, eaves and ridge are most exposed, and unfixed tiles can be lifted and dropped back out of line. After a storm it is worth looking along each slope from the ground or an upstairs window; a pair of binoculars helps.

Fallen pieces can be dangerous, so keep people away from the area below until the roof has been checked.

Nail fatigue and old battens

On older slate roofs the iron nails corrode, a problem often called nail sickness. Slates then slip one after another over months or years, even without bad weather. Copper or aluminium nails last far longer, but many older roofs were fixed with ordinary iron.

Battens can also soften with age, particularly where there has been condensation or a long-standing leak. A tile cannot stay put if the timber it hangs on is crumbling.

Replacing a single tile or slate

For a tile, the courses above are eased up slightly, the broken piece is removed and a new one is hooked over the batten and fixed where needed. For a slate, the old nails are cut out and the replacement is secured with a strap or clip that holds its tail, because the nail holes are hidden under the slate above.

This is small, precise work. Done carefully, it does not damage the surrounding tiles and the repair is hard to spot from the ground. Our roof repairs page covers this kind of job alongside leaks and ridge work.

Matching old concrete, clay and slate

Concrete interlocking tiles come in many profiles and some older ranges are no longer made, so the shape must fit the interlock as well as look right. Clay plain tiles weather to a softer colour over decades, so a brand-new tile may stand out at first. Natural slate varies in size, thickness and colour between sources.

Good matches can often be found from reclaimed stock, or by moving original tiles from a less visible slope to the front and using new ones at the back. The aim is a repair that keeps the roof watertight and still looks like one roof.

Is a slipped tile urgent?

One slipped tile does not always leak straight away, because the felt or membrane underneath acts as a second line of defence. That layer is not designed to take rain for long, though, and older bitumen felt can be torn or brittle. Water reaching the battens and rafters causes rot that is far more expensive to put right.

Treat it as a repair to arrange soon rather than leave for months, and sooner still if you see damp in the loft or a stain on a ceiling. Our guide to why roofs leak covers other possible sources.

When a slope needs re-roofing

If tiles or slates are slipping in several places, if the nails are rusting through across the roof, or if lifting a few pieces reveals rotten battens and perished felt, replacing individual pieces becomes a cycle with no end. Re-covering the slope with new membrane, battens and fixings deals with the cause.

The factors that set the price of that work are explained in our new roof cost guide, and roof repair cost explains how smaller jobs are priced. We look at the roof, explain the options and give a clear written quotation before any work starts, and our new roofs page describes the re-roofing side of what we do.

Frequently asked questions