Jargon Buster

Building roofs is quite technical and so sometimes we use technical language. Sorry about that. However, to keep things simple we've designed a manual to explain and translate many of the commonplace words and terms used in the conservatory industry.

Each reference includes a list of alternative words ("also known as"), a full description of the product/component and, where relevant, a picture to illustrate its relevance.

To find the explanation for your term simply browse alphabetically below.

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Safety Glass

Also known as: Toughened glass, laminate glass or Georgian wired glass. There are different types of safety glass but the most prevalent is toughened glass. Toughened glass is made by quickly heating the pre-cut sheet glass and air cooling it rapidly, changing its molecular structure. Laminated glass is produced by permanently bonding two pieces of glass together with a tough plastic interlayer (polyvinyl butyral) under heat and pressure. The benefit of laminated glass is that if broken, glass fragments adhere to the plastic interlayer rather than falling free and potentially causing injury. Georgian wired and laminated glass are not used very often in conservatories.

Sand Blinding

Also known as: Levelling material. Layers of sand that cover the compacted hardcore within a base.


Also known as: Levelling compound. Layer of concrete floor to level for the fitting of floor tiles.


Also known as: Low modulus, Rotabond, Gutterbond. Special sealants are used by installers for achieving leak-free conservatories. The two main types are as follows: Low modulus neutral cure silicone.

Sealed Unit

Also known as: Double glazed unit, IGU.

Secondary Seal

Also known as: Hot melt. A secondary seal on an IGU.


Also known as: Solar heat gain coefficient. Solar heat gain coefficient refers to heat from the sun which penetrated glass units, resulting in heat gain. It is expressed as a fraction; i.e. 0.40 = 40% of the sun's heat penetrates the conservatory.

Slotted End

Also known as: Fabricated end. See fabricated end (the image shown is a slotted fabricated end for a lean-to). Formed from aluminium.

Snow Load

Also known as: Snow drift. Snow load refers to the amount of snow that should be able to settle on the roof of a conservatory without it collapsing under the resulting weight. Conservatories in Britain are typically designed to a snowload of 0.6Kn/m2 (equivalent to 2 foot of snow per m2).


Also known as: Runaway. A hole that's dug typically 5m away from property for water to run into.


Also known as: Weathering tray, lip, upstand. A preformed upstand which lead or conservaflash is pressed into.

Soffit Board

Also known as: Under eaves board, Roofline. A soffit board is the horizontal board that lies at 90 degrees to the fascia; i.e. parallel to the ground.

Soft Coating

Also known as: Sputtered microscopic layers. Soft coating is the coating applied to the outside face of the inner pane to significantly improve unit thermal performance. Pilkington K is a hard coat product, St Gobain (the other leading glass manufacturer) produces soft coat products.

Soil Vent Pipe

Also known as: Foul Stack. Main vertical pipe which waste water and foul water run into.

Solid Floor

Also known as: Slab, plinth. A concrete floor slab constructed and supported directly from the ground.


Also known as: Spacer bar. A spacer is a packer (usually metal) which forms a cavity width within a double glazed unit.

Spanning Performance

Also known as: Span. Spanning performance is the term used to describe the ability of a structural member to carry snow and wind loads between fixed points; e.g. glazing bars, ridges. The larger the span, the more demanding the specification is the achieve the span.


Also known as: Spider arms. A speedlock is the device used to connect square cut glazing bars to the ridge end.

Splayed Bars

Also known as: Angled bars. Glazing bars that cross (& fasten to the eaves beam) at any angle other than 90 degree.

Split Valley

Also known as: Bent valley, Cut valley. A split valley occurs where the valley meets the eaves beam. If the external angle exceeds 90 degrees the valley wind (on the facet side) will need to be scored, folded and then bolted to the eaves beam, to enable the glazing material to lay flat.

Squint Bricks

Also known as: 135degree formed bricks. Typically formed at 135 or 150 degrees to offer 'feature' corner facets to a brickwork dwarf wall.

Staggered Jacks

Also known as: Stepped jack rafters. Jack rafters either side of a hip bar that are not back to back.

Starter Bar

Also known as: Wall bar, end bar, gable end bar. The starter bar is the end bar on a roof which either sits tight to a wall or fits on each end of a lean-to roof.


Also known as: Outlet. A conservatory roof stockist is someone who simply stocks conservatory roofs to sell them non via a trade counter to installers; i.e. they do not manufacture or install products.

Stop End Outlet

Also known as: Wall outlet. A stop end outlet is used when a run of gutter stops with a rain water pipe outlet.

String Line

Also known as: Setting out point. Used by bricklayers to form set out lines for straight brick work building (corner to corner).

Structural Bar

Also known as: Glazing bar. See 'Glazing Bar'.

Structural Integrity

Also known as: Vertical and lateral stability. A well designed conservatory has structural integrity; i.e. it takes account of wind and snow loads and incorporates features to make it fit for purpose, e.g. includes TBRK, Bolster, etc.


Also known as: Super hero!!. A surveyor is the person responsible for site evaluation and measurement to ensure the conservatory to be manufactured and built will be suitable for the site conditions.

Suspended Floor

Also known as: Floating floor, block and beam. A suspended floor is a floor construction raised and suspended above the internal ground level and generally supported by the perimeter cavity walls, with possibly load bearing internal masonry walls to reduce the span of the floor.

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