Ridge, Hip, Verge And Valley: The Parts Of A Roof

Key takeaways

• Naming the part turns a vague call into a specific one, which changes what a roofer can tell you.
• The apex is the ridge, the sloping gable edge is the verge, the bottom edge is the eaves.
• External angles are hips and internal angles are valleys, and the difference matters enormously.
• Most of the words people struggle with describe junctions, which is also where roofs fail.
• You do not need to use the terms correctly to be taken seriously, but it helps to recognise them.

The ridge, at the top

The ridge is the horizontal line at the apex where two slopes meet. The tiles capping it are ridge tiles, and on older roofs they are bedded in mortar while modern work uses a mechanically fixed dry ridge system. If somebody refers to the ridge board they mean the timber inside the roof that the tops of the rafters meet. What goes wrong: mortar cracking and losing its bond so tiles work loose, gaps opening between ridge tiles, and in a dry system the fixings or clips failing. Because the ridge is the highest and most wind exposed line, a loose ridge tile is a falling hazard as much as a leak.

Hips and valleys, which are opposites

A hip is an external angle where two slopes meet and turn away from each other, running down from the ridge to a corner of the building. A valley is an internal angle where two slopes meet and turn towards each other, forming a channel. Hips are capped with hip tiles bedded or fixed like a ridge, sometimes with a hip iron at the bottom to stop them sliding. Valleys are lined with lead, a preformed trough or an open metal channel. They fail differently: hips lose their bedding, valleys block with debris and back water up under the tiles either side.

The verge, at the gable end

The verge is the sloping edge of the roof where it stops at the top of a gable wall, running from eaves to ridge. Traditionally it is finished with mortar bedded over an undercloak, a strip of slate or fibre cement board that supports the bed. Modern work uses a dry verge, a clipped plastic or metal trim. The verge weatherproofs the edge and restrains the end tiles, and it is the second most wind exposed line on the roof. Missing mortar here is not merely untidy; it releases the tiles most likely to be lifted by wind.

The eaves, at the bottom

The eaves are the lowest edge of the roof, where the rafters project beyond the wall. The fascia is the vertical board across the rafter ends, which carries the gutter. The soffit is the horizontal board underneath, closing the gap between fascia and wall. A bargeboard does the same job as a fascia but runs up the sloping edge at a gable. The eaves are where water leaves the roof, where the underlay must discharge into the gutter, and usually where ventilation enters the roof space, which makes it a busy few centimetres.

The covering, and the words for the pieces

Tiles or slates are laid in courses running horizontally, and each course overlaps the one below by a distance called the headlap. A double lap covering, used for plain tiles and slates, means any point on the roof is covered by two thicknesses. A single lap covering, used for interlocking tiles, relies on a profiled side joint instead. A tile hangs on the batten by a nib, a small projection on its back edge. A verge tile, an eaves tile and a top course tile may all be different sizes from the general field, which is why replacement is not simply a matter of buying a tile.

Underneath: battens, underlay and torching

Battens are the horizontal timbers fixed across the rafters that the covering hangs from, spaced at a gauge set by the tile size and the required lap. The underlay, sometimes called sarking felt, is the continuous sheet beneath them acting as a secondary barrier. On very old roofs neither felt nor membrane exists and you may instead find torching, a lime and hair mortar applied to the underside of the slates to close the gaps, which crumbles and falls into the loft over the decades. Counter battens, where present, are vertical timbers creating a drainage and ventilation gap beneath the battens.

The structure, in the loft

Rafters are the sloping timbers running from the wall plate at the eaves to the ridge. The wall plate is the horizontal timber bedded on top of the wall that they sit on. A purlin is a horizontal beam running across the rafters partway up to shorten their span, carried by gable walls or by struts standing off an internal wall. Ceiling joists run across at ceiling level, tying the rafter feet so the roof cannot spread. A modern trussed roof replaces all of that with prefabricated triangulated frames, which is why a loft full of light timber webs looks so different from one with heavy rafters and a purlin.

Lead, and the pieces it is formed into

Wherever the roof meets something vertical, lead does the work, and each piece has a name. The apron is the piece worked over the tiles on the lower face of a stack. Running up either side, the metal is cut to follow the brickwork in a series of steps, each tucked into a joint. Soakers are individual pieces interleaved with the tiles beneath a step flashing. A back gutter sits behind a chimney, catching water coming down the slope above it, and is the piece most often omitted. A cover flashing or abutment flashing seals where a roof slope meets a wall. Cavity trays sit within the wall to divert water outward.

The chimney, from the top down

The pot is the fired clay cylinder at the top of a flue. The flaunching is the sloping mortar bed on top of the stack that holds the pots and sheds water away from the openings. The stack is the brickwork itself, and the flue is the shaft running down inside it. A capping cowl covers a disused flue while allowing ventilation. Where a stack meets the roof, the correct treatment is the leadwork described above; the grey wedge of mortar sometimes used instead is a cement fillet, which is a substitute rather than a detail.

Rainwater goods

The gutter runs along the eaves and is held by brackets fixed to the fascia. Where two lengths meet, the connector is a union or a union bracket, containing the rubber seal that usually fails first. The outlet is where the gutter discharges into the downpipe, and a hopper head is the open funnel sometimes used instead. The swan neck is the pair of angled bends just below the eaves where the downpipe steps inward to meet the wall. At the bottom, a shoe directs the discharge into the gully, a small chamber with a trap connecting to the underground drain.

Flat roof vocabulary, which is different again

A flat roof is never truly flat; it is laid to a fall, the slight slope that moves water to an outlet. Firrings are tapered timbers that create that fall on a level deck. The deck is the boarded surface the covering is laid on. An upstand is the part of the covering turned up vertically against a wall or kerb. A kerb is the raised timber around a rooflight or opening. Ponding is water standing on the surface after rain, and an outlet is where water leaves, with an overflow being a second opening set higher to reveal a blockage.

Using the words without worrying about them

Nobody expects a homeowner to be fluent, and a roofer would far rather hear a plain description than a misapplied term. Where the vocabulary genuinely helps is in three places: describing where a problem is, so somebody attends prepared; reading a quotation, so you can tell what is included; and comparing quotes, since two documents describing the same work in the same words are comparable and two describing it differently are not. If you take three terms from this, take ridge, verge and valley, because those three cover most of what goes wrong on a pitched roof.

How to describe a problem on the phone

The most useful call gives four things: the type of building, where on the roof, what you can see, and what has happened inside. Something like a nineteen thirties semi, the gable end facing the road, a gap where the mortar has gone about halfway up the sloping edge, and a damp patch on the bedroom wall on that side. That description tells an experienced roofer the likely cause, the likely access requirement and roughly what it will involve before anybody has left the yard. Compare it with a leak in the bedroom, which requires an entire visit to reach the same point.

Words for things that have gone wrong

A second vocabulary describes faults rather than components, and it is worth recognising. Nail sickness is the corrosion of fixings causing scattered slipping across a roof. Delamination is a slate absorbing water and separating into layers, which makes it sound dull when tapped. Spalling is the face of a brick or tile flaking away after frost. Ponding is water standing on a flat roof after rain. Blown render or plaster has lost its bond and sounds hollow. Efflorescence is the white crystalline deposit left when salts are carried out of masonry by moisture. Each of these names a specific mechanism, and using the right one immediately narrows what somebody needs to look at.

The words for the work itself

Quotations use their own terms and they are not interchangeable. Stripping means removing the covering. Relaying or recovering means putting a covering back, either the original material or new. Repointing renews the surface of a mortar joint. Rebedding lifts a component and beds it in fresh mortar, which is a considerably bigger job than repointing and the two are frequently confused. Dressing means working lead into shape. Making good means repairing incidental damage caused by the work. Snagging is the list of minor defects addressed at completion. Reading a quotation with those distinctions in mind is often the fastest way to see what is actually being offered.

Where the terms come from

Much of this vocabulary is centuries old and regional variation survives, which is why two roofers may use different words for the same thing without either being wrong. A verge is sometimes called a barge. Soakers are known by other names in some areas. Torching, flaunching and haunching all describe mortar in specific positions and get used loosely. This is a reason not to worry excessively about precision: the person you are speaking to will interpret a clear description far more reliably than a term used uncertainly, and asking what they mean by a word in a quotation is entirely reasonable rather than a display of ignorance.

A short glossary to keep

Ridge: the apex. Hip: an external angle running down from it. Valley: an internal angle forming a channel. Verge: the sloping edge at a gable. Eaves: the bottom edge. Fascia: the board carrying the gutter. Soffit: the board beneath it. Batten: the timber the covering hangs from. Underlay: the sheet beneath the battens. Headlap: how far each course overlaps the one below. Flashing: lead closing a junction. Apron, step flashing, soaker, back gutter: the pieces of lead at a chimney. Flaunching: the mortar on top of a stack. Fall: the slope on a flat roof. Upstand: the covering turned up against a wall.

Reading a roof from the street

Put together, the vocabulary lets you describe an entire roof from the pavement in a couple of sentences, which is what a roofer does automatically. A hipped roof in concrete interlocking tile, mortar bedded ridge and hips, mortar verge to the gable, cast iron rainwater goods, single stack on the party wall with a cement fillet at the base. That description carries the age, the likely construction, the probable maintenance history and the two most likely defects, before anybody has been closer than the far pavement. Learning to read a roof that way is not a professional skill so much as a habit, and it is the thing that turns a wall of unfamiliar words into something useful.

What to write down when something goes wrong

Keep it to five things and you will have given anybody what they need. Where on the roof, using the terms here or a plain description of the position. What you can see, described physically rather than interpreted. When it happens, and in what weather. What is happening inside, and in which room. And how long it has been going on. Written that way and sent with two photographs, one wide and one zoomed, it turns a callout into a visit somebody has prepared for, and it is comfortably the most effective thing a homeowner can do to get a useful answer quickly rather than after three visits.

The parts nobody mentions until they matter

A few components only enter the conversation when something has gone wrong, and they are worth recognising. A cavity tray sits within a cavity wall above an abutment, catching water inside the wall and directing it back outward, and its absence causes damp that appears entirely unrelated to the roof. A hip iron is the small metal bracket at the foot of a hip stopping the tiles sliding. A dry verge unit, a ridge union and an eaves comb filler are all modern components with specific jobs and specific failure modes. A soaker is the individual piece of lead interleaved with tiles beneath a step flashing, invisible once laid, and the piece most often left out.

Frequently Asked Questions

What is the difference between a hip and a valley?

They are opposite angles. A hip is an external angle where two slopes meet and turn away from each other, capped with hip tiles. A valley is an internal angle where they turn towards each other, forming a channel lined with lead or a preformed trough. Hips lose their bedding; valleys block and back water up.

What is the verge on a roof?

The sloping edge where the roof stops at the top of a gable wall, running from the eaves to the ridge. It is finished with mortar over an undercloak on older roofs, or with a clipped dry verge trim on modern ones, and it both weatherproofs the edge and restrains the most wind exposed tiles.

What is the difference between a fascia and a soffit?

The fascia is the vertical board across the rafter ends at the eaves, and it carries the gutter. The soffit is the horizontal board underneath, closing the gap between the fascia and the wall, and it often contains the ventilation into the roof space. A bargeboard does the fascia's job on a sloping gable edge.

What is flaunching?

The sloping bed of mortar on top of a chimney stack that holds the pots in place and sheds water away from the flue openings. It sits in the most exposed position on the building and cracks over time, which lets water into the joint between pot and brickwork and down into the flue.

What is a back gutter?

The piece of leadwork behind a chimney stack, catching water running down the slope above it and directing it around the stack. It is the piece most frequently omitted or done badly, and because it handles the concentrated flow from everything above, its absence causes a disproportionate number of chimney leaks.

What does headlap mean?

The distance by which each course of tiles or slates overlaps the course below. It is what keeps water out, since nothing on a pitched roof is sealed. Insufficient headlap produces a roof that looks entirely normal and leaks in driven rain, which is why it is a specification rather than a matter of judgement.

What is torching in a loft?

A lime and hair mortar applied to the underside of slates on older roofs to close the gaps, used before underlay became standard. It crumbles over the decades and falls onto the loft floor, and finding it there indicates a roof with no secondary barrier beneath the covering.

Do I need to use the right words when I call a roofer?

No, and a plain description beats a misapplied term. Where the vocabulary helps is in describing where the problem is so somebody attends prepared, and in reading and comparing quotations. If you learn three terms, learn ridge, verge and valley, since those cover most pitched roof faults.

What is a soaker?

An individual piece of lead interleaved with the tiles beneath a step flashing at a chimney or abutment. Each one sits under a tile and turns up against the wall, with the step flashing covering the upstands. They are invisible once laid and are among the pieces most often left out.

What is the difference between repointing and rebedding?

Repointing renews the surface of a mortar joint. Rebedding lifts the component off entirely and beds it in fresh mortar. On a ridge that has genuinely worked loose, pointing addresses the visible joint and leaves the tile just as loose, so the two are very different jobs at very different prices.