Here To Help


2 facet conservatory

A conservatory which has 2 sides to the front.

3 facet conservatory

A conservatory which has 3 sides to the front.

5 facet conservatory

A conservatory which has 5 sides to the front.

Air conditioning

A system which can generate cold and warm air via a fan to control the required temperature.

Argon Gas

An inert gas used in sealed units with high insulating properties.

Base wall

A cavity brickwork wall onto which the conservatory will sit (between 300 mm and 750 mm high).

Boundary line

This is normally the dividing line between properties, usually a fence or another physical barrier.

Building Warrant

Written permission from a Local Authority permitting construction of a house, extension or conservatory.

Colour Wash

A term used to paint a wall (a term used in the 1930's-1960.s to white washed ceilings).

Combination conservatory

Normally a conservatory that possesses two or more conservatory styles within it e.g. 3 facets and sun lounge.


A decorative upright moulding on the top of a conservatory which also helps to stop the birds from sitting on the roof.

Crown top conservatory

A large 3 facet conservatory which incorporates a small flat roof at the top to allow structurally for this larger design.


Damp Proof Course normally laid 150 mm above ground level.


Damp Proof Membrane this is laid between the sand blinding of the hardcore and the oversite concrete to prevent damp rising up through the floor.

Dental moulding

A decorative moulding normally below the guttering of the conservatory.

Double glazed unit

Two pains of glass hermetically sealed with a gap between them also known as a sealed unit.

Dwarf wall

A cavity brickwork wall onto which the conservatory will sit between 300 mm to 750 mm high.

Equal site lines

This is when both open and non opening parts of a window look the same.

Eaves beam

The beam above the window frames of the conservatory which supports the roof.

External Cill

A special moulded section at the bottom of a window or door that allows the rainwater to run off and not run down the brickwork of the base wall making it damp.


The pointed part of the cresting.

Flank wall

Normally a side wall of a conservatory built on or near a boundary. Flashing a lead covering between the roof of a conservatory and the brickwork of the house onto which it is fixed which prevents rainwater from penetrating down the back of the conservatory.


The brickwork from the top of the foundation to the D.P.C. of the conservatory.


The concrete strip cast into the ground onto which the footings the conservatory are built.


Structural window frames manufactured to accept the weight of the conservatory roof.

Gable conservatory

A conservatory that has a gable front (like the end of some houses that forms a point).

Garden Room

A conservatory that has a roof that slopes from the rear to the front.

Glazing bars

PVCu or timber bars that divide a window into sections e.g. a Georgian window.

Glazing Beading

A PVCu or timber cover beading which secures the sealed unit (glass) into the window frame.


A device to collect rainwater from the roof of the conservatory.

Inspection Chamber

Usually a chamber which contains underground sewage pipes or services.

Internal cill

A window board or tiling that covers the cavity at the top of a dwarf wall.

K glass

Pilkington "K" Glass varies from normal clear glass as one side of the glass has a special metal coating, known as a low emissitivity coating. This microscopic metal coating (which is almost indistinguishable from normal clear glass) allows through short-wave radiation, like sunlight, but reflects long-wave radiation, such as heat from fires and radiators, back into your conservatory making it easier to keep warm. As this coating on the glass makes the surface warmer to the touch, condensation is also reduced.

Lead time

A period of time allowed before the next stage takes place i.e. placing an order and then waiting for a delivery.

Lean to conservatory

A conservatory that has a roof that slopes from the rear to the front.


Usually a chamber which contains underground sewage pipes or services.


A silicon bead which is injected by hand to seal a small gap and to form a seal between the uPVC frames of conservatories to the brickwork of the house.


The material used to bond bricks together when building a brick wall.

Multipoint locking

A locking system for doors and windows that locks in at least two points. Usually windows have 3 positions and doors 5 positions including 5 lever dead lock.


The construction of the concrete floor to the conservatory.

Piled foundation

A specialist foundation used where ground conditions are poor e.g. a brown field site.

Planning Permission

Written permission from a Local Authority permitting development of a house, extension or conservatory.


A smooth finish which is laid onto a brick or block wall which can be decorated.


A plastic roof covering for a conservatory roof which is supplied in clear, opal and bronze.


A gate way or opening.

Ring beam

The beam above the window frames of the conservatory which supports the roof.

Roof Ventilator

A opening window in the roof of a conservatory to allow ventilation.


An opening part of a window.


A smooth light sharp sand and cement finish laid onto the oversite when all the major building works have been completed onto which you can lay floor tiles or carpet etc.

Sealed manhole cover

A special metal double sealed cover with 4 screws fixed to the top of the chamber level with the floor finish preventing gas from the chamber entering the conservatory or any other room.

Sealed unit

Two pains of glass hermetically sealed with a gap between them also known as a double glazed unit.

Self cleaning glass

A special nano-scale - extremely thin - coating of microcrystalline titanium oxide which reacts to daylight. This photocatalytic reaction breaks down filth on the glass, with no need for detergent. When it rains, a hydrophilic effect is created, so water and dirt slide off.

Skirting boards

Timber moulded boards which are fitted at the bottom of walls and then decorated.

Squint Brick

A special made angled brick which can be used in building a base wall of a 3 facet Victorian conservatory.

Sun Room

A conservatory that has a solid roof.

Tie Bar

A metal rod or timber member to prevent the conservatory from spreading (Lateral movement the sides of the conservatory moving away from each other).

Top fanlight

The top part of a window above the transom bar.

Top hung sash

An opening window either hung below a transom bar or a full length opening window not to be confused with a fanlight which is a small opening window.

Transom Bar

The part of the window which divides the window in two.

U factor

A factor used for calculating heat loss the lower the U factor the higher the insulation.

Unequal site lines

This is when the opening part of a window stands proud of the non opening parts of the window.

Wall ties

Metal restraint wires approximately 3 mm thick which link the two cavity walls together to give it strength and assist in weathering.

Windows and Doors  

A-rated window

British Fenestration Ratings Council (BFRC) energy ratings are a simple, clear and easily understandable method of informing customers about the relative energy efficiency of particular products. Windows are rated on an A to G scale, in the same way as white goods, light bulbs and other consumer products. An A-rating indicates the most energy efficient products, a G-rating the least efficient.


Another name for a soffit.

BBA - British Board of Agreement.

The BBA is the UK’s major approval body for new construction products and installers. BBA Agreement Certificates are recognised by specifiers and other industry decision-makers as proof that the products covered by them have been rigorously assessed, will comply with Building Regulations and will last for a defined period.


Beads clip in to the window profile to hold the double glazing in place.

Bifold door

A contemporary door system comprising three or more large glass panes which fold back fully upon themselves to create a large opening.

Building Regulations

Building Regulations are Government codes which set out the criteria that new building projects and refurbishment work must conform to. They help to ensure that buildings are safe, secure and energy efficient.

Butt hinge

A hinge that allows the full closing of a door or window. Butt hinges stand proud of the door or window surface.


The term used to describe a conventional window, with a sash that is side or top hinged. Casement windows open outwards.


Window cill. The protruding lip that directs water away from brickwork at the bottom of a window opening.

Composite door

A robust, secure style of door that looks and feels like a traditional timber door. It’s made from an outer skin of GRP (Glass Reinforced Plastic) over a wooden frame infilled with foam insulation. (Also known as a traditional door)


The process of extruding a PVC-u profile and its gasket simultaneously.

Curtain walling

Glazed walling used in large buildings, often several storeys high.


A secure locking system used in modern doors.

Double glazing

Glazing made up of two layers of glass with a space between them to improve insulation and reduce noise. Double glazing comes in several widths, although 24mm and 28mm are the most common.


Most of the profiles used in PVC-u windows, doors, conservatories and roofline are extruded. Extrusion is the process of pushing PVC-u pellets through a die to form a solid shape.


Part of the roofline system that seals a house from the elements, between the tiles and the brickwork. Fascia is the front vertical board on the complete roofline system. Fascia is also sometimes used as the collective word for roofline.

French doors

Double outward-opening doors that meet in the middle without a mullion, giving a clear unobstructed opening.

French windows

Double outward opening windows that meet in the middle without a mullion, giving a clear unobstructed opening.


The black rubber strip that runs around the pane of glass in a window to create a weatherproof join.


Glass Reinforced Plastic, also known as fibreglass. GRP is a composite material made of a plastic reinforced by fine fibres of glass. GRP is an extremely tough material used in the marine industry for its hardwearing and weatherproof characteristics. GRP is also used as the outer skin on composite doors.

Head drip

Head drips appear at the top of a window and are a means of channelling water away from the front face of the window or door.


A type of door lock that throws a hook or multiple hooks into a keep when the door is locked.

Inline patio door

A sliding patio door system where the moving door pane slides in front of the fixed pane.

Injection moulding

The manufacturing technique used to make parts from both thermoplastic and thermosetting plastic materials in production. Molten plastic is injected at high pressure into a mould, which is the inverse of the product’s shape. Moulds are made from either steel or aluminium and are precision-machined to create the features of the desired part.

Low ‘e’ glass

Low ‘e’ stands for low emissivity glass. This glass varies from normal clear glass in that one side has a special metal coating, technically known as a low emissivity coating. Low ‘e’ glass is a type of insulating glass which works by letting in energy from the sun while blocking heat loss from the home.

Main frame

The section of profile used to construct the outer frame of a window.


A mullion is the vertical structural element which divides adjacent window units.

Outer frame

An alternative term for the main frame of a window system.

PAS 23/24

PAS 23 – General performance of doors / PAS 24 – Enhanced security. PAS23/24 are accreditations that test the performance and security of doors.

Pilkington Activ

Pilkington Active™ is self-cleaning glass. In a dual-action process, organic dirt is broken down by daylight and is then washed away by rain, thus making it easier to keep clean.


Polyvinyl Chloride – Unplasticised. The rigid plastic used to manufacture windows and doors. PVC-u provides low maintenance coupled with long life. The term PVC-u is often misunderstood. Mis-spellings include PVC, PVC-U, U-PVC, UPVC, PVCu and uPVC. PVC-u is sometimes also referred to as just plastic, e.g. plastic windows.


Polyvinyl Chloride – Unplasticised expanded. Often referred to as foam products. PVC-ue is used to manufacture many roofline products. PVC-ue has a hard external finish and a slightly less dense core than PVC-u.


The opening portion of a window.

Self-cleaning glass

Glass that uses a dual-action process in which organic dirt is broken down by daylight and is then washed away by rain, thus making it easier to keep clean. Pilkington Activ and St Gobain Bio-clean are brand names for this type of glass.


An alternative spelling of cill.


Part of the roofline system on a house that seals the house from the elements, between the tiles and the brickwork. Soffit is the horizontal part that runs from the fascia back to the house wall.

St Gobain Bio-clean

St Gobain’s brand of self-cleaning glass. In a dual-action process organic dirt is broken down by daylight and is then washed away by rain, making windows easier to keep clean.


A transom is the horizontal structural element that divides adjacent window units.

Thermal break

A way of stopping heat or cold transfer between two surfaces. In windows, thermal breaks are often used within the double glazed unit – see warm edge spacer.

Tilt and turn

A window system that opens inwardly in two ways. Tilt and turn windows swing completely inwards allowing for easy cleaning. They also tilt at the top to provide good ventilation without leaving the window fully open.

Trickle vent

A ventilation system built into the top of the window frame.


A measure of heat loss. The lower the U value, the more energy efficient the window.

Vertical slider

A window in the style of a traditional vertical-sliding sash window. Our PVC-u sliding sash windows allow both the top and bottom frames to slide freely. The frames also tilt inwards for ease of cleaning.

Warm edge spacer

A new innovation that replaces the aluminium spacer. Used to separate the two panes of glass in a double-glazed unit with a spacer made of a different material (often plastic) that transmits less heat. This makes the window more energy efficient.

Secured by Design

Secured by Design (SBD) is the UK Police flagship initiative supporting the principles of “designing out crime”. Windows and doors that carry SBD approval have been assessed to provide a high degree of resistance to break-ins.

Make your house a home! Let Mitchell Glass take care of it – get in touch with us today and see how we can help.

Get a free quote

or call us today on 0800 220 415.

Customer Reviews

Very good.

Windows & Doors Galashiels
Vivian Webster – 29th Oct 2020

Excellent Job done by Mitchell Glass from start to finish. The two fitters Michael and Kieran found they had a...

Windows & Doors Galashiels
Robin Brashier – 26th Oct 2020

A difficult one to organise due to covid restrictions and delays in production out with Mitchell’s control but I felt...

Windows & Doors St Boswells
Claire McPhee – 28th Sep 2020

Very smooth process, always prompt replies to any questions. Delighted with our new windows are door. Thank you.

Windows & Doors Edinburgh
Mary Traynor – 24th Sep 2020

We are highly delighted with our sunroom it is very smart and it is comfortable and wish we had done...

Windows & Doors Galasheils
James Fisher – 28th Aug 2020

Kevin and Stephen were very professional and friendly. Very pleased with workmanship.

Windows & Doors Uddingston
Mr W Swann – 18th Jun 2020

Get directions to our showroom


All content © R Mitchell (Glass) Ltd

Authorised and regulated by the Financial Conduct Authority.

R Mitchell (Glass) Limited at Currie Road Galashiels TD1 2BP (VAT No. 272 252 081).  Financial Services Registered No. 808089 is a credit broker and is authorised and regulated by the Financial Conduct Authority. Credit provided by Hitachi Personal Finance, a trading style of Hitachi Capital (UK) PLC, authorised and regulated by the Financial Conduct Authority (Register No. 704348).