Abutment - The junction between a roof and a vertical structure.

The most common weatherproofing system used for abutments is lead flashing.

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Apron - A type of flashing used for abutments situated at the top of a slope.

Usually a sheet of lead embedded into a vertical structure then dressed over the roof covering beneath it.

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Barge Board - The boards fixed to the overhanging verges of a roof.

Barge boards are used to strengthen the roof structure but also hide and protect the otherwise exposed ends of the horizontal timbers or purlins to which they are attached.

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Batten - Lengths of treated softwood most commonly used for supporting tile and slate.

Laid horizontally over the breather membrane, secured to the rafters, battens are often seen in different colours ranging from green to red. 

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Back Gutter - A form of flashing used to weatherproof abutments situated at the bottom of a slope.

Often found where the back of a chimney meets the roof. Back gutters are usually made from lead.

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Bitumen Felt Underlay- A water repellent membrane that acts as a secondary weatherproofing barrier.

Bitumen felt is an inferior product when compared with modern breather membrane as it restricts ventilation, so it's usually reserved for circumstances where breather membrane is prohibited. For example, if the roof space is inhabited by bats.

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Breather Membrane - An air permeable, water repellent membrane.

In roofing applications, the membrane is used as an underlay which sits between the rafters and battens and acts as a secondary barrier to weather conditions such as rain, wind, frost and snow whist still allowing the roof to breath.

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Cladding - A material used to cover exterior walls. 

While most commonly used for aesthetic purposes, cladding also increases thermal insulation and the weather resistance of a building.

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Cold Roof - A roof that contains the insulation layer within its structure.

A ventilated space sits between the insulation and the outer roof covering. This is the most common roof insulating system however it's no longer recommended for flat roofing as it can be difficult to achieve the level of ventilation required.

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Counter Batten - A batten mounted vertically up the roof in-line with the rafters.

Counter battens are usually used in warm roof applications in which insulation boards are situated directly beneath the breather membrane. The counter battens are laid vertically then the regular horizontal battens are laid on top of them. This is so any moisture that makes it through to the breather membrane is able to run down to the eaves without getting caught behind horizontal battens laid flat against the insulation boards.

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Course - A horizontal row of tiles or slates.

The number of courses on a roof is dependent on the headlap required to sufficiently weatherproof the building.

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Dormer - A structure with a roof that protrudes from a larger roof.

Often containing a window, dormers come in many different shapes and sizes. Some of the most common types are:

Gable fronted dormer - two sloped roof surfaces form a front facing gable.

Hip roof dormer - three sloped roof surfaces form two hips.

Shed roof dormer - a dormer with a mono pitched roof.

Flat roof dormer - a dormer with a flat roof.

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Dormer Cheek - The vertical sides of a dormer.

Common dormer cheek coverings include lead, tiles, uPVC cladding and wooden cladding.

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Down Pipe - An escape route pipe for water collected by the gutter.

Downpipes are part of the roofs guttering system and come in a range of materials however uPVC is the most common. Cast iron is a premium choice and is often used when a traditional aesthetic is required.

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Eave - The bottom of the slope on a pitched roof.

More accurately defined as the section at the bottom of a roof slope that overhangs the wall beneath it however roofers often use the word when referring to the bottom course of slates or tiles.

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EPDM - A single ply, rubber flat roofing system.

EPDM is an extremely durable, synthetic rubber weatherproofing membrane. It stands for Ethylene Propylene Diene Terpolymer.

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Fascia Board - The horizontal board that sits beneath the eaves.

The fascia hides the ends of the rafters and closes the gap between the walls and the roof.

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Flashing - A weatherproofing system used at abutments.

The type of lead flashing used in any given situation will be dependent on factors such as roof covering, roof pitch, exposure etc..

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Gable - The triangular face that's formed when a roof with two sloped surfaces joined at the ridge ends abruptly.

There are many types of gable roof such as the box gable, cross gable, Dutch gable etc..

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Gauge - The distance between each course of slates or tiles. 

The maximum gauge is determined by the minimum required headlap. In most cases the roofer will seek to have an even gauge all the way up the roof, so a measurement will be taken from the ridge to the first batten. This will be divided by the maximum gauge and rounded up to the nearest whole number. The original measurement will then be divided by the whole number to give us our gauge measurement.

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GRP - A fiberglass-based roofing system.

GRP is a heavy-duty weatherproofing system used for flat and low pitch roofing. It stands for Glass Reinforced Plastic which is an incredibly versatile material allowing for complicated designs and intricate details. Most commonly seen in anthracite grey but available in a range of colours.

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Headlap - The amount a course of tiles/slates is overlapped by the next.

The minimum headlap is mainly dictated by the pitch of the roof, the lower the pitch the more headlap required. 

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Hip - A sloped ridge. The external vertical junction between two slopes.

There are many types of hip covering which include hip tiles, lead roll hips and close mitre hips. Hip tiles are the most common. Traditionally bedded with mortar, guidelines now encourage roofers to mechanically fix the tiles with modern dry ridge systems which have proven to be a more reliable, longer lasting solution.

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Hip Iron - A metal peg fixed at the bottom of a hip to prevent the hip tiles from slipping.

Used as a precaution in the case of mortar failure. Hip irons aren't necessary when tiles are mechanically fixed with dry ridge systems.

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Lath - Another word used for roofing batten.

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Lead Slate - A form of lead flashing used for pipes that protrude through the roof covering.

Sold in various sizes designed for various pitches.

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Lean-to Roof - A roof in which the rafters lean against a wall.

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Mitre Joint - A seamless union between two or more parts facilitated by perfectly angled cuts.

Mitre joints are often seen on hips and ridges.

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Mono Pitched Roof - A single surface, single pitched roof. Sometimes referred to as a "shed" roof.

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Mono Ridge - The ridge of a mono pitched roof.

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Mortar - A mixture of sand, cement and water.

The ratio of sand and cement we use for roofing mortar is one part cement, one part sharp sand and two parts building sand.

 

Parapet - A low wall that runs along the edge of a roof.

 

Pitch - The angle of a slope.

 

Pitched Roof - A sloped roof.

 

Purlin - A horizontal beam that runs along the length of a roof.

 

Rafters - The parallel beams that run from the wall plate to the ridge. 

Rafters are what make up the majority of timberwork in a pitched roof structure.

 

Raking Cut - A diagonal cut across multiple courses of slates/tiles.

Raking cuts are seen when it's not possible for the tiles/slates to sit parallel with the verge.

 

Ridge - The apex of a pitched roof.

Ridges are most commonly covered with ridge tiles. Traditionally bedded with mortar, guidelines now encourage roofers to mechanically fix the tiles with modern dry ridge systems which have proven to be a more reliable, longer lasting solution.

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Roof Covering - The material/product used as the primary covering of a roof.

Examples of pitched roof coverings are natural slate, fibre cement slate, clay pantiles, rosemary tiles, concrete plain tiles, interlocking clay tiles, interlocking concrete tiles and shingles.

Examples of flat roof coverings are EPDM, GRP, torch felt and lead.

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Secret Gutter - A hidden abutment gutter.

Usually accompanied by cover flashing, secret gutters are used as a precautionary measure in the case of cover flashing failure.

 

Soaker - A strip of sheet metal, folded at a right angle and inserted between slates/tiles at abutments.

Soakers form one component of a two-part flashing system. The other component usually being stepped flashing.

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Soffit Board - The board fixed to the underside of overhanging eaves, often to match the fascia.

 

Truss - A frame consisting of rafters, posts and struts.

Pre constructed triangular timbre frames lowered onto wall plates.

 

Undercloak - The strip that runs along a verge to which slates and tiles are bedded onto.

Most commonly 150mm wide fibre cement strips but plain tiles are sometimes used instead. 

 

Underlay - Breather membrane or bitumen felt underlay.

 

Valley - The internal junction between two slopes.

 

Valley Gutter - A gutter that runs down the centre of a valley.

Usually made from lead, GRP or tiles. We prefer lead valley gutters for slate roofs and GRP valley gutters for tiled roofs.

 

Verge - The vertical edge of a gable roof or mono pitched roof.

Traditionally, verges have been mortar bedded however due to the inevitability of mortar cracking, dry verges are becoming the favoured option for most of our customers. 

 

Warm Roof - A roof with a continuous insulation layer installed outside of the structural frame, directly beneath the roof covering.

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