The short answer
Most tiles should be mechanically fixed, with a nail, a clip or both. BS 5534 is the code covering this, and it varies the fixing with pitch and exposure, so a sheltered low roof and an exposed steep one are treated differently. It is not a law, but a tile resting on its own weight can lift in wind, so a repair should clip or nail it down.
Clips, nails and the standard behind them: what is recommended, why it varies from roof to roof, and what a sound repair looks like.
What BS 5534 actually asks for
BS 5534 is the British Standard that guides slating and tiling on pitched roofs, and the current edition is BS 5534:2014+A2:2018. It describes how tiles and slates should be secured so that wind cannot strip them. Marley, a tile maker, says plainly that working to BS 5534 is not required by law. Even so, it is the yardstick roofers, tile makers and surveyors use to judge whether a roof is fixed properly.
The standard leans on mechanical fixing, meaning a nail, screw or clip, and not on the weight of the tile and its nibs alone. How many tiles in a course get a fixing, and of what kind, depends on pitch, building height and exposure. Each maker's data sheet turns those variables into a fixing schedule for its product, and that sheet is the document to follow.
BSI cautions that period roofs are a special case: when an old roof is re-covered with traditional or salvaged materials, the standard's advice may not suit it. On a period house the roofer should use judgement and explain it, rather than simply applying a table.
Why pitch and exposure change the answer
Wind does two things to a roof. It pushes against the windward slope, and it pulls upward on the lee side and across the top. A tile on a steep slope is held along the pitch by its own weight, while a tile on a gentle slope leans harder on its fixing. The taller the building and the more open the site, the greater the lift, so a hilltop house or the end of a terrace faces more than a sheltered street.
Edges suffer most. Verge, eaves and ridge see the strongest suction, so those tiles are fixed more heavily, with verge clips along the gable edge and eaves clips at the gutter line. A verge clip is a small metal hook gripping the tile's edge, and an eaves clip stops the bottom row creeping or lifting.
Minimum pitch comes into it as well. A low-pitch product such as Marley's Mendip 12.5, rated to 12.5 degrees, is designed for a gentle slope with the fixings its data sheet demands. Check any change of product against your roof's angle. Our answer on roof tiles lifting in wind shows what failure looks like.
Ridge and hip tiles: mortar alone is not enough
The ridge is the crest of the roof, formed where the two main slopes meet, and a hip runs down an outer corner. Those tiles were once simply bedded in mortar. Marley explains that after the 2014 revision, a mortar bed is no longer treated as enough to keep ridge and hip caps in place on its own; every bedded tile or fitting also gets a clip, screw or nail. Mortar can still be used; it just cannot be the only thing holding the tile.
Dry-fix systems answer this with clips, screws and ventilated sections in place of a wet bed, and Dry-fix kits for verge, hip and ridge are tested to BS 8612. Our answer on mortar valley cracking covers the other place mortar turns up.
If your ridge has crumbling mortar, loose caps or a tile that rocks when pushed, ask the roofer whether the plan is to re-bed with mechanical fixings or to put in a dry-fix kit. Checkatrade's June 2026 repair table gives typical UK ranges of £50 to £70 per metre for dry ridge and £70 to £100 per metre for dry hip repairs. Treat those as yardsticks.
Our single total is fixed after the survey and names the system and fixings we propose.
What this means for a repair or a new roof
For a repair the rule of thumb is simple: a replacement tile should be secured the way its neighbours are, and where the neighbours have no fixing at all, the roofer should say so. A tile that slips on an old roof laid without clips often points to thin original fixing, and an extra clip on the new tile costs little and guards against a repeat.
If the survey finds a large share of tiles loose with nothing holding them, that is evidence for re-roofing rather than patching. Battens should be sound and the tiles in decent shape before a new fixing schedule goes on, because fixing a tired tile only gives it a better chance of cracking in place. Our survey photos show those findings.
On a new roof or a re-cover, ask for the fixing method in the written quote: which tiles are nailed, which are clipped, and what is used at verge, eaves and ridge. Our pitched roofing page describes the wider job. For a first look, attach a ground-level snap of your verge and ridge, and we will explain what that edge detail needs.
More on this in Pitched Roofing Services in Crawley
Two more fixing questions
Can I add clips to my existing tiles myself?
Not safely. Clips go on at the tile edges, often at the ridge, verge or eaves, which means working at height on a surface that breaks under a boot. Clips also have to suit the tile profile. A roofer can fit the right ones during a repair, and the written price covers it.
Does an old roof without clips fail a survey?
Not automatically. Many older roofs were laid before today's guidance and have stood for decades. A surveyor looks at the condition of the tiles, battens and fixings, and at how exposed the site is. The question is whether the roof is performing, and a roofer's photos help answer it.