Wood window glossary

Last Updated: 5 September 2022

Window Infographic


This is where wood, more specifically Accoya® wood, is subjected to a vinegar which turns into a hardwood by preventing the cells in the wood from being able to absorb water.

The Accoya timber is treated with acetic anhydride. It doesn’t turn the wood into hardwood but does alter the timber at a molecular level so that the cells don’t absorb moisture in the same way. This is partly where the timber gains its long life and strength 

Accoya® wood

Accoya® wood is a highly desirable and high performing engineered European Redwood software that provides a sustainable alternative to tropical hardwoods.

Our Reddish Joinery Accoya® windows are sustainably sourced and fully recyclable, making them one of the most environmentally friendly windows on the market.

Butt hinges

Butt hinges, more specifically black, brass, or stainless-steel butt hinges, are probably the most common hinges which can be found around the house. They are used on timber doors, casement windows, and other pieces of furniture.

You can also get rising butt hinges which have two leaves that are joined by sliding one over the other via a pan. This allows the door to rise slightly when opened, preventing any dragging sound when opening.

CNC router

A CNC wood carving machine is a computer numerical control (CNC) router, or a CNC machine as some may call it, that creates objects from wood. Using a CAD/CAM program on a computer, we’ll design a project (door, window, conservatory) on a computer and then automatically cut using the router.

Our new precision woodworking machinery boosts production times, creates better quality products and enhances our bespoke packages.

Glass and Glazing Federation (GGF)

The Glass and Glazing Federation (GGF) provide extra protection to glass manufacturers should any company cease to trade before the guarantee has expired.


There are many different types of wood for timber windows, with the main two categories being hardwood (ash, beech, or mahogany) or softwood (cedar, fit, or pine).

The thing that defines hardwood from softwood such as pine is the presence of special pores in the cellular structure of the wood itself. Their complex structure gives them great dimensional stability and durability.

Heritage windows

These are suited to period properties such as Victorian properties or historic properties such as 19th Century properties and are either made from natural timber or high-performance uPVC that replicates the authentic appearance of timber windows.

Laminated glass      

In simple terms, laminated glass is a glass sandwich comprises of a piece of plastic interlayer sandwiched in between two pieces of 3mm thick glass.

The advantage of laminated glass is that when smashed, it holds its shape and doesn’t shard into thousands of tiny glass pieces.

Multi-chamber window profiles

Incorporating symmetrical chambers within the window profile, multi-chamber window profiles work to trap pockets or warm air, ultimately retaining the heat in your home and helping to reduce your electricity bills too!

Nine-chambered frame

The nine-chambered frame, also known as the Residence 9, is designed to replicate the flush sash timber windows found on 19th Century properties and is one of the most authentic systems on the market. Each of the nine chambers helps trap pockets of air, providing excellent energy efficiency whilst helping to keep your electricity bills low.


Fitting inside the window frame, the sash (or “sashes”) is the section that moves and holds the glass panes safely in place.


Softwood makes up about 80% of the world’s source of timber and usually comes from evergreen conifer trees like pine or spruce. Versatile, hard performing and durable, softwoods are one of the most sustainable types of timber available. This makes it perfect for our Reddish Joinery timber windows.


Sustainably sourced and attractive in the most classical sense, our selection of timber doors is elegantly constructed to deliver the most authentic look and feel of traditional wood panels.


In simple terms, the u-value refers to how well heat is transferred by the window, frame, or glass. In technical terms, it means the thermal efficiency of a window. As a good gauge of measure, the lower the u-value, the more efficient the window, so for example windows with a 0.7/0.8 u-value are highly efficient windows.

Woodgrain foils

A foil is a type of finish that is applied to a window frame to achieve a particular texture or aesthetic. At Reddish Joinery we have a variety of foils available to choose from including Golden Oak, Eclectric Grey, Corse Lawn, Clotted Cream, and many more!

Window Energy Ratings (WER)

So, you’ve chosen the dream windows for your home which is great. But how can you tell how energy-efficient those windows are?

Well, the WER will do exactly that. Similar to the rating system used on white household goods, the rating system is based on a scale of E to A++ with the latter being the most energy-efficient. With thanks to the use of multi-chambered profiles such as the Residence 9, our windows are able to attain an WER rating of A and above. To put this into context, if replacing single glazing with A-rated double glazing on a semi-detached house, your energy bills can be reduced by £65-£70 per year!

Get in touch with Reddish Joinery today. We are available to call on 0161 969 7474 or you can contact us online.

Read our related blogs:

Why you should choose Reddish Joinery when looking for a timber front door

Are wooden sash windows better than uPVC sash windows?

Are wooden back doors secure?

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