Roof Tiles Jargon Buster 


Struggling to tell your Bargeboard from your Bonnet hip? Worry not – help is at hand. We've compiled a glossary of the basic roofing terminology you'll find scattered all over this site. These words may seem like a foreign language at first, but it's not too hard to get a grasp on the basics pretty quickly:

Where a roof meets the side of a wall, dormer or chimney.
The highest point of the roof where the two slopes meet.
Arris hip
A hip tile ordered specifically to suit the roof pitch.
Board fixed to the roof at the gable end.
A length of timber which is mounted horizontally across the rafters to locate and/or secure the tiles or slates.
Batten gauge
Often referred to as ‘the gauge’. This is the measurement determined by the tile for batten spacing. It is the distance from the  top of one batten to the top of the next batten below. Correct batten spacing is essential for a weather tight roof.
Batten Void The area above the underlay and below the roof covering.
Block end ridge
A special ridge tile for use at the gable end. Often used with cloaked verge tiles.
Describes the way tiles are laid - eg Half bond, broken bond cross bond
Bonnet hip
A hip tile used in plain tiling with a raised front edge for ease of pointing.
Broken Bond See Half Bond.
Aluminium, steel or plastic device to secure tile to the roof structure beneath.
Cloaked verge
Special tiles designed to turn down at the verge as an
alternative to using mortar.
Counter batten
A batten mounted vertically up the roof along the lines of the rafters. These are normally used where the roof frame has been boarded to give a space when the underfelt and battens are fixed.
A horizontal row of tiles.
Cold Roof
A roof design where the insulation is laid between the ceiling joists (ie over a normal flat ceiling).
Condensation Where hot air meets cold air, condensation is formed. For example, where heat rising from the inside of the house meets the cold underside of the roof covering, condensation occurs.
Cowl Ventilators
A cowl tile ventilator has a cowl or cap on the top of the ventilator (sticks out above the roof line).
Concealed Ventilators
A concealed tile ventilator has an in-built grill which is inset into the ventilator (does not stick out above the roof line).
Cross Bond See Half Bond
Dentil Slip
Decorative piece of clay or concrete used to fit under ridge/hip tiles, bedded in mortar and designed to reduce the depth of mortar bedding.
Discontinuous Laying A European term meaning small individual roof coverings, i.e roof tiles opposed to large continuous roof sheets.
Double lap
Description for roofing materials without interlocking channels (see single-lap).
Double lapped tiles
Tiles with no interlocks. Water drains between the tiles onto the tile below. At any point of the roof there is at least a double layer of tiles, at the headlap there are three layers of tiles.
Dry Ridge
A system used to fix the ridge tiles without the use of sand/cement mortar. A secure system of fixing comprising a range of plastic rails, unions, fixings and fittings, often offers ventilation at the ridge too. 
Dry Fix Methods of fixing and weatherproofing roofing details without the use of mortar.
The draining edges of the roof (the part of the roof above the gutter).
Eaves fillers
Plastic sections (individual or 1m combs) fixed on top of the fascia board to prevent birds and vermin entering the roof.
Fascia board
Timber or PVC board found at the eaves (behind the guttering). Usually fixed to the wall.
Decorative end ridge tile with vertical feature
(i.e. fleur-de-lys).
Fixed gauge
See gauge. Where the gauge is a specific or “fixed” measurement the roof may not work out in full courses and a course of shortened tiles is needed.
Impervious strips fixed at junctions to make them weather tight. Lead is normally used for this purpose but other materials are also available.
Gable Roof
A type of roof where the roof ends encloses the end walls. The triangular wall between the roof verges is called a gable end.
Gable end
The end wall where two verges meet.
Gable tile
A special tile or slate which is 1 ½ times the width of a normal tile or slate to allow courses to be laid ‘broken bonded’.
The measurement from the top of one batten to the top of another batten this equates to the overall length of the slate/tile less the specified overlap.
Hanging tiles
A general term which is applied to tiles fixed to vertical walls.
Also known as broken or cross bond. Describes the laying pattern where the tile/slates are laid half way across the course below (all double lap materials).
The measurement of the overlap of one course of slates or tiles over the course below (used to work out the batten gauge). Usually expressed as a maximum or minimum measurement in millimetres, defined by the tile or slate manufacturer.
Where two sloping roofs meet at an external corner of the house.
Hip Board
The board along the line of a hip, from the fascia to the ridge of the pitch.
Hip End
A sloping end to a pitched roof which is covered with slates or tiles.
Hip End Ridge
A ridge tile that is used at the end of the ridge, where it meets 2 hips.  Suitable for use with plain tiles with bonnet, arris or mitred hips, also suitable for use with slates with mitred hips.
Insulation Membranes For example, a rigid insulation board. Insulation facing membranes are supplied to the construction industry to boost insulation properties in residential and commercial properties. These membranes include re-inforced aluminium foils that provide a good vapour barrier and reflective properties. When combined with suitable insulation, they offer Class 1 and even Class 0 fire performance.
Left-hand-verge tiles
Special tiles designed to neatly finish off the left hand side of the tiling so it is in keeping with the rest of the roof (i.e. double roll pan tiles). 
Linear cover
Also known as the effective width, this is the visible width of a tile/slate once laid on the roof.
Materials cut so they form a close fit.
A roof with two pitches, the first is steep and the second shallow to allow for extra height in the attic.
Roof with an angle spanning two walls which are of different heights.
The horizontal line running along the top of a single roof slope at the apex.
Mortared Junction For example, a three way mitre, where two hips meet a main ridge. The ridge tiles would be mortar bedded where the junctions meet.
Overhang The distance that the undercloak extends over the verge (usually 38-50mm)
A single lap tile which gives the appearance of ‘waves’ and troughs’ on the roof.
Angle of the rafters – measured in degrees. Defined by the tile or slate manufacturer and very important because all tiles/slates have a minimum pitch.
The use of mortar or cement to fill the gap between the tile and the under cloak at the verges.
A horizontal length of timber that provides support to rafters.
A vertical, sloping timber used to form the shape of the roof - the side of a truss.
Reconstituted Slate
A modern, manufactured product which consists of crushed natural slate which is bound together using resins.
The horizontal line running along the top of the two roof slopes at the apex.
Ridge tiles
Semicircular or angular tiles typically 300mm or 450mm in length used to provide a finish at the apex. Usually secured by mortar or a dry-fix system (see dry ridge).
Roof Junctions Is the detail where two or more roof slopes meet, for example, a ridge line, a hip or a valley.
A surface application of sand or small chippings which enhance the appearance and improve weathering properties of roof tiles.
Another name for roofing underfelt/underlay
Sarking Board
Sarking is wood boarding used under tiles or slates to provide support to the underlay, commonly used in Scotland.
A flashing that fits over tiles at junctions between two or more roof slopes (tops of valleys, hips etc).
Short course
A short course of tiling is needed when the tiles do not work out in full courses. This would mean cutting the top off the tile and re drilling a hole to fix the tile.
Side lap
The distance which one tile/slate is off-set from the edge of the one below (see also half bond).
Single lap
Description for roofing materials such as concrete interlocking tiles and fixed gauge clay tiles that rely upon an interlock at the sides of the tile to provide waterproofing (see also double-lap).
Single lapped tiles Tiles that have side interlocks and drainage channels to drain away the water .
Soakers are small sections of watertight material (usually lead) used with slates and plain tiles, typically underneath a step flashing at abutments or between courses at a mitred hip or valley.
The materials used to close the eaves between fascia board and main structural wall.
The distance between the walls which support the roof.
Sprocket piece
Timber sections used (often on steep roofs like steeples) at the eaves to reduce the pitch of a roof slope in order to slow the rainwater down before reaching the gutter.
Standards The British Standards are a guide to how materials should be fitted and fixed.
Sub roof
The structure of the roof below the tiles or slates. Includes battens, underlay, boarding etc.
Under cloak
Sections of slate/tile/fibre-cement strip used at the verge to provide a bedding key for the mortar at overhangs.
A small strip of lead, zinc or copper, nailed to the batten under a displaced slate, the slate is then replaced and the bottom of the tingle is bent up over the bottom edge of the slate and back onto the front surface to hold it in place. Usually a temporary repair for an old roof as their use can be a sign of 'nail sickness'.
Tilting Fillet
Allows for the first course of tiling to ‘sit’ at the correct pitch.
A factory made roof frame.
Also referred to as “Under felt”. Description for sheet materials manufactured from bitumen based or plastic materials used under the battens to protect the roof from the ingress of wind, dust and moisture.
The line between two roof slopes at an internal corner.
Variable gauge
A non fixed gauge. See gauge. Courses of tiles and slates with variable gauges can be freely adjusted to ensure short courses can be avoided.
Verges are the outer edges of the roof area above the gable ends.
Vertical Tiling Sometimes known as 'tile hanging', where roofing battens are fixed to a vertical surface such as a wall or dormer cheek. Plain tiles are then fixed to the battens. 
Wall Plate
Length of timber which is fixed to the top of a wall to secure the rafters.
Warm Roof
A roof design where the insulation is laid between the rafters (ie following the roof line).


Further Reading

The Housebuilder's Bible - 9th Edition

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My Building Project Directory

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How To Get Planning Permission

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The Green Building Bible - Volume 1

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Renovating For Profit

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 Home Extensions

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Building Green

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Home: A short history of an idea

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