The short answer
Roof tile clips are small metal hooks that hold a tile down by its lower edge, so wind cannot lift it or let it slide. They are used where a nail alone is not enough, along the eaves, at the verge and across the main slope of many roofs. BS 5534 is the British Standard that guides how tiles are fixed.
What a clip actually does
A tile clip is a bent strip of corrosion-resistant metal that hooks over the lower edge of a tile and is fixed to the batten beneath. The batten is the timber strip across the rafters that the tiles hang from. The clip stops the tail of the tile, its free lower edge, from lifting when wind blows up the slope.
That lifting matters because roofs behave like aerofoils. Air pushed over a ridge creates suction on the far slope and pressure that pushes under loose tile edges. A tile held only by its top nail can flap, rattle and eventually crack or slide off.
A clip also helps in the other direction. On a steep slope, a tile can creep downwards over the years, and a clip at the tail holds it where it was laid. It is a small component, and it only works if it matches the tile profile, so the clip for one tile is wrong for another. We take the tile maker's data sheet as the guide, and we fix the clip to a batten that we have first checked is sound, because a clip fixed to soft timber holds nothing.
BS 5534 and mechanical fixing of the main field
The code for slating and tiling pitched roofs is BS 5534, and the BSI Knowledge listing shows BS 5534:2014+A2:2018 as current. Marley states that installing to it is not demanded by law. Even so, it sets out how tiles on the main field and the edges are fixed, and we fix tiles to it.
The main field is the plain area of tiles across the middle of a slope, away from the edges. Mechanical fixing there means nails and clips gripping the timber, rather than leaning on the weight of the tile or on a mortar bed. Marley's account of the 2014 revision is that mortar by itself was no longer to be counted on at the ridge and hips, and BS 8612 is the standard that dry-fixed ridge, hip and verge units are tested to.
In practice the fixing pattern depends on the tile, the roof pitch and the exposure. We follow the tile maker's guidance rather than guessing, and say so on the survey. If an older roof was laid before clips were common, that is a finding to explain, not a fault to blame on anyone.
Clips versus nails
A nail goes through a hole near the head of the tile and holds the top of the tile to the batten. It does the job of resisting slide. It does little against a tile's tail being lifted, and every extra nail also adds a hole in the tile and a point of corrosion.
A clip works on the other end of the tile. Fitted at the tail, it resists uplift directly, and no extra hole is needed in the tile. A tile that is both nailed and clipped is held at both ends, and that combination is common on exposed edges and on tiles with a low profile, which are more easily lifted.
Interlocking tiles, those with grooves along their sides that lock into the next tile, also help: the side lock stops sideways movement. Some roofs rely on that profile and fix only every few courses. The pattern is set by the manufacturer's data sheet and by BS 5534, so any roofer who fixes by habit alone is guessing. Our page on interlocking roof tiles describes the profiles, and shows why a clip for one profile will not suit another.
Wind uplift at verges and eaves
Wind has most to work with at the verge, where the tiles stop at a gable end, and at the eaves, the low edge above the gutter. Air can reach the underside of the tile from the side or below. Uplift is stronger at the edges, so the fixing there is closer and stronger than in the middle of the slope.
On a roof with a dry-fix verge system, the verge tile is held by a clip or a mechanically fixed trim, not by mortar alone. An old mortar bed at a verge can crack and fall away, and a loose end tile can go in a blow.
If tiles have started to lift, look at why roof tiles lift in the wind, and for the wider picture our pitched roofing hub covers tile types, battens and repairs. The right number and position of clips is part of the survey: we count what is there, photograph it and tell you if the roof needs more before the next storm. Where a few edge tiles are loose, the fix is often local, with a handful of clips and new nails.
