Hip Tiles: Arris, Bonnet, Third-Round and Why the Pitch Angle Matters

A homeowner orders 50 clay arris hip tiles for a new extension. They pick the colour, pay the supplier, take delivery. The roofer arrives and the tiles do not sit flush against each other. There is a visible kick-out on every tile. The tiles cannot be returned (custom-pitch order, used pallet) and cannot be reused on the next job because no other roof in the area shares this exact pitch. That order of clay tiles becomes garden edging. The cause: the homeowner ordered the 45 degree variant when the roof pitch was actually 40 degrees. Hip tiles are pitch-specific in a way ridge tiles never are, and getting the angle wrong is the most expensive ordering mistake on the whole roofing job.

What they are and what they're for

Hip tiles close the external angle where two pitched roof slopes meet at a corner running from the eaves up to the ridge or apex. On a hipped roof, instead of the gable wall going up to the ridge, the roof slopes inward on all four sides, and the diagonal lines where adjacent slopes meet are the hips. Without hip tiles, those diagonal junctions are open seams that wind-driven rain blows straight through.

A hip tile is not the same as a ridge tile. Ridge tiles cap the horizontal apex where two slopes meet at the top. Hip tiles cap the diagonal corners where two slopes meet on the side. The shapes are different, the fixing is different, and on plain tile roofs, hip tiles are a category of their own with bonnet and arris variants that have no ridge tile equivalent. Plenty of homeowners (and a few roofers) confuse the two and order ridge tiles for hip work. They look almost right when delivered, look obviously wrong when fitted.

Hip tiles also house the hip iron, a small piece of galvanised or stainless steel that anchors the bottom hip tile to the hip rafter. Without the hip iron, the bottom tile slides down the hip line under its own weight and gravity does the rest to the tiles above it. This is the single most common cause of hip end failure on older roofs.

Hip tiles are made from the same material as your main roofing tiles. Clay tiles need clay hip tiles. Concrete tiles need concrete hip tiles. Mixing materials produces colour mismatch within a few years and the profiles will not align. They also need to come from the same manufacturer and ideally the same range, because clay batches and concrete pigments vary between producers.

Hip tile types and which one you need

Five types of hip tile cover almost every UK pitched roof. Choosing the right one depends mainly on what your main tile is.

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A simple decision: if your main tile is a profiled concrete interlocking tile (Marley Ludlow, Redland Grovebury, Sandtoft Double Roman), use a third-round or angular concrete hip tile. If your main tile is a plain clay tile (Dreadnought, Sandtoft, Tudor, handmade peg), use an arris or bonnet clay hip. If you have a flat interlocking tile or a slate roof, an angular ridge tile on the hip is standard.

For a heritage or listed building, the choice often comes down to what was originally fitted. Bonnet hips were the traditional finish on Victorian and Edwardian plain tile roofs in much of England; arris hips were more common on later 1920s to 1960s tile work. Match what is there now unless you have a specific reason to change.

Arris hips: the pitch trap

Arris hip tiles are the most common cause of expensive ordering mistakes. The tile is angular and asymmetric, designed to sit precisely over the hip junction at one specific pitch. Order the wrong angle and the tile will not sit flat. Even three or four degrees out produces a visible kick-out at every joint and gaps that water blows through.

UK clay arris hips are typically sold in four pitch variants: 35°, 40°, 45° and 50°. Some manufacturers (Marley, for example) describe these as the "tile included angle" instead, where 130° equals a 50° roof pitch, 135° equals 45°, and 145° equals 35°. Both notations mean the same thing but they catch out homeowners ordering online without checking.

You also need left-handed and right-handed arris tiles in alternate courses. Most suppliers sell them as a matched set or specify the handing in the order. Ask the supplier to confirm before paying.

Bonnet hips: more forgiving but slower

Bonnet hips do not have a specific pitch angle baked into the tile shape. The bonnet is a rounded hood that sits over the hip junction, and the adjacent main tiles are cut to butt against the underside of the bonnet. This makes bonnets more flexible on unusual or unequal pitches.

The catch is that bonnet hips are slower to install. Each tile is bedded in mortar, supplementary battened to prevent the mortar sagging, and the adjacent main tiles in every course need cutting to match. A skilled roofer will produce a beautifully even bonnet hip line. A rushed one will produce snaking, uneven joints, and excessive mortar overflow. The straightness of the bonnet line from eaves to ridge is the most visible quality indicator on the whole roof and the most cited complaint in homeowner forum threads.

For both bonnet and arris hips, the two roof slopes meeting at the hip should share the same pitch. Unequal pitches are possible but require special detailing or move you toward a mitred hip with soakers.

The hip iron: small part, big job

The hip iron is a small galvanised steel hook fixed to the bottom face of the hip rafter at the eaves. It sticks out a few centimetres beyond the rafter end. The first (lowest) hip tile is laid over the top of the hip iron, and the iron physically prevents that tile sliding down the hip under gravity. Every tile above the first relies on the first one staying in place. If the bottom tile slips, the whole hip run can come away.

A standard galvanised hip iron is 300mm long, 150mm wide on the angled face, 3mm thick, and made to EN10327:2004. Stainless steel variants are available for exposed coastal sites where galvanised steel will corrode within 20 years. £2 – £5 per piece. Stainless steel variants carry a modest premium over galvanised.

The hip iron has to be fixed before any hip tiles are laid. It nails or screws into the lower end of the hip rafter through pre-drilled holes in the iron. NHBC inspectors check for the hip iron at every hip end on new builds. Mortar alone, without a hip iron underneath, is the single largest cause of hip end failure: the mortar cracks, the bottom tile loses its restraint, and the whole hip line eventually slides off the roof.

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If you are inspecting a finished roof from the ground, you can see the hip iron poking out at the very bottom of each hip line, just above the gutter. If you cannot see one, ask the roofer where it is. If the answer is "we just used cement," the work does not meet BS 5534 and a warranty inspector will fail it.

Dry hip vs mortar bedding: what the rules require

The same regulatory shift that affected ridge tiles applies to hips. BS 5534:2014+A2:2018 requires every hip tile to be mechanically fixed. Mortar alone is not enough, no matter how thick or well struck the bedding looks. Mortar tensile strength is explicitly excluded from wind uplift calculations under the current standard. NHBC paid out substantial warranty claims for failed mortar-bedded ridge and hip tiles before the rule changed, which is what drove the update.

Two compliant approaches exist:

1. A proprietary dry hip system that conforms to BS 8612:2018. Marley HipFast, Klober, Manthorpe and similar kits use mechanical clips into a hip batten with a ventilated roll that bridges the tiles. No mortar.
2. Mortar bedding with supplementary mechanical fixing. A nail, screw, or proprietary clip is added to each hip tile alongside the mortar. The mortar provides the visible finish and weather seal; the fixing carries the wind uplift load.

For new extensions, dry hip is the default. The materials cost more upfront but the install is faster, the lifetime is longer, and BS 5534 compliance is automatic. £100 – £130 for a Marley HipFast 6-metre system pack.

For period properties or listed buildings, lime mortar (not sand and cement) is the right answer when matching original detailing. Sand-and-cement mortar is too rigid for handmade clay tiles, which expand and contract with temperature more than concrete tiles do. The cement mortar cracks within a few years and the tile slips. Lime mortar flexes with the tile.

How to work with hip tiles

You will not be installing these yourself. This is scaffolded roof work and requires a roofer. What you need to know is what a competent installation looks like and what to inspect before you sign off.

The correct sequence on a new hip:

1. The hip iron is fixed to the lower face of the hip rafter at the eaves end, with stainless or galvanised screws, before any hip tiles are laid.
2. For a dry hip system, a hip batten is installed along the length of the hip rafter, with the dry hip clips and ventilated roll laid in.
3. For mortar bedding, the underlay is dressed up to the hip with a 150mm overlap on each side; for dry hip, a 30mm gap is trimmed to allow ventilation.
4. The first hip tile is positioned over the hip iron and bedded or clipped down. This is the anchor for the entire hip run.
5. Adjacent main tiles are cut to butt against the hip tile (not the other way round). Hip tiles always go on first; the main tile course is cut to suit.
6. Subsequent hip tiles run up the hip in a straight line from eaves to ridge, each mechanically fixed and either bedded in mortar or clipped into the dry system.
7. At the apex, the hip tiles either meet a ridge tile (most pitched roofs) or terminate in a four-way hip cap if it is a pyramid roof with no ridge.

The minimum underlay overlap at a hip is 150mm. Less than this and wind-driven rain finds its way under the tiles and onto the hip rafter. Ask to see this before the tiles go on, or check it from inside the loft space if you can access the hip area.

How much do you need

Hip tiles are sold per tile. The number you need depends on the length of each hip and the coverage rate of the tile.

For standard clay arris hips: roughly 9 to 10 tiles per linear metre of hip. Some traditional handmade clay tiles run longer and give about 8 per metre. The supplier will state coverage on the product spec.

For third-round hips (concrete or clay): 3 to 4 tiles per metre at standard 300mm to 450mm lengths.

Worked example: a single-storey rear extension with a hipped roof has two hip lines, each 3.5 metres from eaves to ridge. That is 7 metres of hip in total. For arris hips at 9.5 per metre, you need 67 tiles, plus 5% for breakage (4 tiles), so order 71 in total. You also need 2 hip irons (one per hip line), and either a dry hip kit covering at least 7 metres, or sand, cement, plasticiser, and supplementary mechanical fixings if mortar bedding is used.

For a full hipped main roof on a detached house, hip lengths of 6 to 8 metres are typical and there are usually four hips. That is 24 to 32 metres of hip work, requiring 230 to 320 hip tiles plus four hip irons. The numbers add up quickly; budgeting for hip materials separately from main tile materials is essential when comparing roofer quotes.

Cost and where to buy

Hip tile pricing varies by material (clay always more than concrete), shape (third-round cheapest, arris middle, bonnet often pricier), and brand (Dreadnought premium, Marley and Sandtoft mid, generic budget).

For the most common combinations:

For a 7-metre hipped extension roof using clay arris tiles at the mid of the range, that is roughly 70 tiles at £9 – £16 each. Add two hip irons at £2 – £5 each and a dry hip kit at £100 – £130, and the hip materials package for the extension comes to £100 – £130 or more. On a full detached hipped roof, hip materials alone can run considerably higher before any labour.

Installed labour rates (covering both supply and fitting per linear metre):

For the same 7-metre hipped extension, the per-metre rate from the range above gives an indication of hip line cost installed with a dry system. The wide range reflects access difficulty, scaffolding requirements, and whether the roofer is on site for other work or making a single-job visit.

If you are getting a full new extension roof tiled, the hip work is part of the tiling contract and should not be quoted separately at these rates. The per-metre hip pricing applies when hip work is the main job (re-roofing, hip end repair, replacement after storm damage).

Where to buy

For new extensions, order hip tiles from the same supplier and the same delivery batch as your main roof tiles. Major UK roofing specialists (Roofing Superstore, Burton Roofing, Roofing Outlet, RoofGiant, Roofing Megastore) carry the full Marley, Redland, Sandtoft, Russell and Dreadnought ranges. Travis Perkins and Jewson stock the common concrete profiles but limited clay ranges.

For a heritage extension or repair to an older roof, reclaimed hip tiles are the right answer when a colour or profile match to existing tiles is needed. Cawarden Reclaim and Gardiners Reclaims are the largest UK reclamation yards and will deliver pallets nationwide. Reclaimed Brick Company and similar regional yards stock smaller batches.

Reclaimed stock is variable. Order 10 to 15% extra for breakage (handling reclaimed tiles is rougher) and ask for samples first. Pallet delivery typically adds a flat delivery charge on top.

Alternatives

The realistic alternatives to a traditional bedded or dry-fixed hip are limited.

Mitred hip with metal soakers is a flush detail used on plain tile roofs where the visual line of a bonnet or arris is unwanted. Adjacent tiles are cut to a 45 degree mitre at the hip line and weatherproofed underneath with lead, zinc, or aluminium soakers extending at least 100mm each side. It looks neat but requires precise tile cutting and soaker dressing that few general roofers do well. Specialist heritage roofers use this on conservation work where the trustees of a listed building object to visible hip tiles.

Four-way hip caps terminate a pyramid roof where four hips meet at a single point with no ridge. They are pitch-specific (like arris hips) and sold as a single decorative cap that sits over the apex. Common on small single-storey rear extension dormer or porch roofs with a pyramid form.

Continuous lead hip rolls are sometimes used on slate roofs as an alternative to angular ridge tiles on the hip. Heavier visual line, fully waterproof, more expensive, and requires a competent leadworker.

For ridge tiles specifically, see the ridge tiles page. Hips and ridges are different products serving different junctions, but the dry-fix vs mortar decision is the same on both, and most roofs will use a matched approach across both.

Common mistakes

Wrong-angle arris hips ordered. The expensive one. Pitch-specific tiles ordered for the wrong roof pitch cannot be returned and cannot be reused. Always measure the pitch on the roof itself before ordering.

Missing hip iron. The single largest cause of hip end failure on older roofs. If you are commissioning a re-roof or new hip work and the quote does not mention a hip iron at each hip, ask. A low-cost part prevents a costly repair bill when the hip end slides off in a winter storm.

Mortar-only fixing. Non-compliant under BS 5534 since 2014, more strictly enforced since 2018. Building control can fail it. Insurance may decline storm damage claims on non-compliant work. Specify dry hip or mortar with supplementary mechanical fixings.

Wrong tile material. Concrete hip tiles on a clay tile roof, or vice versa. Different weathering rate, different colour after a few years, different thermal expansion. Match material to material.

Different manufacturer. Even within concrete, different makers use different pigment formulations. A Marley hip on a Redland roof will not match within five years. Order all roofing components from the same supplier and the same batch.

Hips fitted after main tiles. Hip tiles must go on first, with main tiles cut to suit. Roofers who fit the main tiles up to the hip line and then try to slot hip tiles into the gaps produce hip lines with snaking, uneven joints, and gaps. The correct sequence is: lay enough courses to reach the hip area, position the first hip tile over the hip iron, then work main tiles up to it course by course.

Snaking hip line. Caused by not using a stringline during installation. The hip line should be visibly straight from the ground from eaves to apex. Step back from the house once the hip is finished and look up at it. If it wanders, that is a quality defect to raise with the roofer before final payment.

Checking your roofer's work

Before signing off the roof covering stage, walk around the building and check each hip line:

1. Hip iron visible at the bottom of every hip, projecting just above the gutter. If you cannot see one, ask where it is.
2. Straight hip line from eaves to apex when viewed from the ground. No snaking, no uneven joints.
3. Mechanical fixing present. On a dry hip, you will see the proprietary clips or the consistent pattern of the system. On mortar bedding, ask the roofer to show you a fixing detail (some clips are hidden under the mortar but the roofer should be able to point them out at one tile to demonstrate).
4. Mortar struck back about 13mm from the tile edge if mortar is used. Excessive mortar overflow is a sign of bad workmanship and creates a thermal bridge for cracking.
5. Adjacent tiles cut neatly against the hip tiles, with no gaps and no exposed underlay visible.
6. Stop ends or finials at the apex where the hip meets the ridge or where four hips converge on a pyramid roof. No open ends.
7. Underlay overlap of 150mm at the hip (visible from inside the loft or before tiles go on; ask if you missed it).

Where you'll need this

• Roof covering - hip tiles close the diagonal junctions on any hipped extension roof and are part of the roof covering stage

Hip tiles appear on any extension or renovation project with a hipped roof form, including single-storey rear extensions with a pyramid or hipped apex, lean-to porches, dormer extensions on existing hipped main roofs, and full re-roof projects on detached houses. They are not used on simple gable-ended dual-pitch extensions where the roof slopes only run front-to-back.