Knowledge Base
The Knowledge Base is designed to help you understand the terminology used within home information pack documents, by people producing them and that you may come across during the sale or rental of properties.
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A mixture of bitumen and fine minerals such as clay which is hot-trowelled onto roofs. The melting point is higher than tar so it has higher weather resistance. Asphalt occurs naturally in Trinidad bubbling up in lakes ready mixed with ...
the upper surface of a slate as laid.
The boards fixed against the roof covering on a gable roof, often timber now usually Upvc.
Treated soft wood, measuring around 25×38mm, which is laid horizontally on top of the sarking felt to hook the tiles or slates on to.
the underside of a slate as laid.
The rounded quadrant shaped tile, which is laid over the hip.
Used on flat roofs to provide weathering and so-called as it is laid in two or three layers. The felts may be standard bitumen based or high performance polymer based - the latter has good flexibility properties. Felts are laid in hot ...
The area under the overhanging part of a roof on the gutter side.
Normally a two or three layers system for boarded flat roofs using cold applied adhesive. Each layer has traditionally been bitumen based, however high performance polymer based materials are available which offer better performance. ...
Normally a two or three layers system for boarded flat roofs using hot bitumen or a flame torch. Each layer has traditionally been bitumen based, however high performance polymer based materials are available which offer better ...
A metal sheet, usally lead, cut into brickwork and then dressed over a surface below, used to deflect water from a joint between two adjacent materials, such as brickwork and tiles.
The sand & cement fillet around a chimney pot.
the distance between the nail hole of a slate and the nail hole of the slate in the preceding course.
top edge of a slate.
the distance the leading edge of a slate overlaps the nail hole of the slate two courses below.
The Health and Safety Commission is responsible for health and safety regulation in Great Britain. The Health and Safety Executive and local government are the enforcing authorities who work in support of the Commission.
also referred to as bachelor slates, are narrow slates which sometimes have to be inserted into courses to maintain the proper width of side lap.
Usually constructed from coloured concrete, interlocking tiles have interlocking edges and hooked tops. The interlocking sides provide weather resistance without the great overlap of plain tiles, so the weight over an area is lower. ...
Traditionally made from concrete with a profile allowing the tiles to overlap each other side to side, so giving much better protection from the ingress of water. Typically 380x230mm with an effective width of 200mm (i.e. 30mm overlap). ...
the distance between the tail of a slate and the nail hole of the slates it covers in the preceding course.
The exposed area of a slate or tile - usually the minimum is quoted by the manufacturer/supplier and may vary for a given slate/tile depending on slope of the roof and exposure - although a different meaning, the measurement is the same ...
Copper nails used to fix slates will corrode in time, particularly with the effects of acid rain in city areas. The result is slipping slates.
is large slates laid with no lap, where the joints are mortared and covered with slate fillets. More usually seen where stone slates are used.
Clay plain tiles that have wooden pegs to hook over the battens instead of the hook formed in tile material. These tiles are found on older buildings and are expensive to replace.
a length of timber marked with half-inch gradations which is used by scots slaters to grade their slates.
The angle of a roof where two slopes meet the ridge. This is referred to as a pitched roof but often incorrectly labeled an 'apex roof'.
The traditional tile is termed flat but has a slight round to spot water creeping up between courses. The size is generally 265×165x10mm thick and the tiling will be three thick at the maximum overlap. This provides the best resistance ...
Similar in colour and size to plain clay tiles, but at lower cost.
A common interlocking tile made in concrete with two indent lines and flexible ridges.
(Scottish) a rectangular metal bar with a spike at right angles at each end, which can be hammered into sarking boards. Used by slaters to dress slates while on a roof. Also referred to as an "edge" or "top edge".
a slater’s knife, used for dressing slates. Usually a heavy blade, off set from its handle, with a 2"
This is the waterproof felt lain immediately under the roof tile battens to keep out wind driven snow and dust. This also acts as a second waterproof layer.
the practice of rounding the top corners of a slate which meant that an uneven slate would sit better but, more importantly, shouldering and single nailing also allows a slate to be swung aside to expose the nail head of the slate below ...
the distance between the edge of a slate and the edge of the slate it part covers in the preceding course.
a slate positioned at the end of a course where it meets a hip or valley, that is at least 1.5 time the with of other slates in the course. Used to prevent water ingress.
the leading edge of a slate.
This link provides a comprehensive set of questions and answers on Thatch and Thatching.
the laying of thicker slates on the wallheads or close to skews so that water runs into the middle of, and down the pitch of the roof, rather tan spilling down the face of gables, or penetrating under mortar fillets.
a metal strip, one end of which can be hooked over a batten or nailed to a sarking board, after which the other end is bent to hold in place a flashing or a slate that has slipped. Sometimes referred to as a "latchet" a "tab" or a "tack".
When faced with slipping slates through nail sickness, there is no easy solution as the slate above prevents access to the damaged nails. In such a situation, it is possible to insert strips of zinc or copper, bent into long 'S' shaped ...
Where tiles or slates overhang the gable bargeboard, the underside is bedded in mortar and finished with special tiles, slates or a inert board, called the undercloaking.
Where two sloping roofs meet, as with two mountains, the valley is the line between.
this is the fan-shaped area that water will cover having penetrated the joint between slates. Clearly the calculation of side lap and head lap becomes very important otherwise water can penetrate through to the sarking or battens
slates which are notched at each side allowing them to interlock to form ridges.
