Joinery quality grades in UK terms

At a glance

Paraphrased from ANSI/AWI 0641-2019 (3.4) and the AWS 1st edition (2009, Section 10, 1.1). US documents: no value is reproduced and none has UK status. HP-1 is the US hardwood plywood standard.

What an AWI grade is, and what there is in the UK

When an American specification says Premium, Custom or Economy, it is asking for a bundle. The Architectural Woodwork Institute (AWI) defines three grades of quality for finished woodwork: Premium is the highest degree of control over materials, workmanship and manufacture, Custom is a high degree and Economy is the minimum. In the AWI's casework standard, ANSI/AWI 0641-2019, a specification that names no grade gets Custom. The grades apply to the completed product, not to a board: the Architectural Woodwork Standards (AWS), 1st edition, say so plainly and add that lumber association grades are not to be used to specify finished woodwork.

The bundle is wide. As the table above shows, a grade changes how well the grain is matched, what veneer may be used, whether the back of a cabinet is required, whether exposed fixings are allowed, how tight the gaps at joints must be, and more. Since 2019 the AWI has been replacing the AWS section by section with ANSI/AWI standards, and in the casework standard the grade is now only the aesthetic half: structure is a separate duty level from 1 to 4, found by testing, with level 3 the default.

There is no British equivalent of the bundle. That is the plain finding of this sheet. British documents cover single parts of it, as the chart shows, and nothing we found sets gap, flushness, finish or veneer limits as a named grade. An AWI grade cannot be translated into a British Standard class. What can be done is to say what each part of the grade controls, anchor each part to a UK document where one exists, and write the rest into the specification.

The British documents, one by one

These are the British documents a UK specification most often cites for joinery quality. None was read in full: they are paywalled, and what is here comes from BSI's listings and from the sources named. Their statuses were as listed on 5 November 2026.

A warning from practice. A public council drawing note from 2014 cites BS 1186-2:1988, BS 8000-5:1990 and BS EN 942:1996 together. The 1996 edition of EN 942 was withdrawn on 30 March 2007 and is replaced by the 2007 edition. Citations go stale quietly, so give the edition and ask the tenderer to confirm it is current.

Where the two worlds touch. Like the AWS, EN 942 is about how timber looks in the joinery part: it classifies appearance at manufacture and can also be used to evaluate a finished product, rather than grading a board in the yard. That makes it the closest UK idea to the AWS's lumber rule, but only for the appearance of timber. It says nothing about veneered panels, which in the AWI standard are tied to the US hardwood plywood grades AA, A and B. We found no UK document that grades veneer faces; the sheet on veneer specification sets out what to state instead.

Where a grade bites: exposed, semi-exposed, concealed

An AWI grade is not applied evenly. The standard divides a piece by how visible each surface is, and sets a different requirement for each zone and each grade. Exposed surfaces are seen with doors and drawers shut. Semi-exposed surfaces, such as the inside of a cabinet and the sides of drawers, are seen when a door or drawer is open. Concealed surfaces, such as the toe space, are not normally seen. The pattern is simple: the better grades ask more of the interior as well as the front. Concealed surfaces are the maker's choice at every grade, while semi-exposed surfaces are held to a compatible species at Premium and left more open at Custom and Economy.

A UK specification can borrow the idea without borrowing the standard. Name the zones, then state what each must be: for example, whether the inside of a wardrobe is the same species and cut as the face, or a different board, and whether the back is required. A surface that was never zoned is a surface whose quality is open to argument.

Translating a grade: what to write instead

Writing a quality level in UK terms is a schedule, not a word. Decide the level for each area, then state each part of the level, anchored where possible:

• Timber appearance: species, cut and appearance class (BS EN 942 class), against an approved sample.
• Veneer and match: species, cut, match and sequence, from the veneer specification sheet.
• Joints and construction: joint types and what is exposed, with BS 1186-2 as the workmanship reference and a mock-up as the proof.
• Gaps, flushness and reveals: a number in millimetres and how it is measured, from the partner workshop and a sample, not from this sheet. The sheet on joinery tolerances and scribing shows the only UK figures we could read and what they are.
• Finish: system, sheen and test, from the sheet on finishes on timber joinery, against a finished sample.
• Installation: BS 8000-5, scribing and fixing, and who supplies backing.
• Strength: where the piece is loaded, a test standard and level (BS 6222-2 for kitchen units, EN 16121 for non-domestic storage), which is the nearest thing to an AWI duty level.

Where each level fits. The AWS says Economy is for work not in public view, Custom for most high-quality work and Premium for the places where the highest quality is needed, and the casework section sets storage, janitor and utility cabinets to Economy unless stated otherwise. That is a useful way to think: a feature wall, a reception desk or a guestroom headboard is where the top level earns its cost, and back-of-house storage is where a plainer level is honest. A UK specification has no default, so say which, and say it per area.

If you write to AWI. A team that chooses the American standard should cite the document and edition (ANSI/AWI 0641-2019 for casework), the aesthetic grade and the duty level, and ask the partner workshop to say in writing, clause by clause, what it cannot meet. The free PDFs of the older AWS leave out its grade rules, though the casework standard's own text is free to read on the AWI website. None of this is a UK requirement.

A quality schedule template

The schedule below is a template with the values left blank on purpose. The numbers belong to the partner workshop, who can deliver and measure them, and to the control sample you approve. They should not be borrowed from an American standard, whose figures have no UK status and are not ours to copy.

Joinery quality level [A / B / C] for [area] as set out in the project joinery quality schedule, revision [ ], agreed with [partner workshop] before tender. For each item and zone (exposed, semi-exposed, concealed) the schedule states timber species and appearance class, veneer and match, joint construction, gaps and flushness in millimetres and how measured, finish system and sheen, hardware and installation. Where this specification and the schedule differ, [ ] governs.

Timber for exposed faces to BS EN 942 class [J10]; workmanship to BS 1186-2; wood trim to BS 1186-3; fixing on site to BS 8000-5, each in the edition current at tender, which the tenderer is to state. These documents do not set gap, flushness, veneer or finish limits: those are in the schedule.

Casework to ANSI/AWI 0641-2019, aesthetic grade [Custom], structural performance duty level [3]. [Partner workshop] to state in writing, clause by clause, any requirement it cannot meet or measure, before tender. AWI references are a design-team choice and are not UK requirements.

A control sample of [item] at quality level [A] is to be approved by [ ] before production. Work is accepted against the approved sample and the quality schedule; gaps and flushness are measured with [ ] at [ ] points per [ ] mm of joint.

Standards and sources

• ANSI/AWI 0641-2019 Architectural Wood Casework: 3.3 and 3.4; US. Read 5 Nov 2026.
• Architectural Woodwork Standards, 1st edition (2009): Sections 3 and 10; grade rules not in the free copy.
• BS EN 942:2007 Timber in joinery. General requirements: BSI listing only.
• BS 1186-2:1988 and BS 1186-3:1990; BS 8000-5:1990: BSI listings only; confirm current editions.
• SATRA, The testing of storage furniture: BS 6222-2, EN 16121:2023.

Questions we are asked

What is AWI Premium grade in UK terms?

There is no UK equivalent. The AWI defines Premium as the highest degree of control over materials, workmanship and manufacture, across grain matching, veneer, construction details, gaps and more. A UK specification has to say each of those things, anchored to a UK document where one exists, such as a BS EN 942 class for timber appearance, and to a sample.

Is BS EN 942 the same as Premium, Custom and Economy?

No. BS EN 942 classifies the appearance of timber in joinery, from class J2 (highest) to J50, by the knots and other features allowed on visible faces. It does not cover workmanship, gaps, finish, veneer or strength, so it covers one row of what an AWI grade controls.

What do BS 1186-2 and BS 1186-3 cover?

BSI lists BS 1186-2:1988 as the specification for workmanship, covering the fit of parts, joints and adhesives, and not applying to wood trim. BS 1186-3:1990 is the specification for wood trim and its fixing. Both are listed as current and under review. We have not read either.

Which level should back-of-house joinery be?

The AWS says Economy is typically for woodwork not in public view, such as mechanical and utility rooms, and its casework section sets storage and utility cabinets to Economy unless stated otherwise. A UK specification has no default, so state a level for each area, and state it for the semi-exposed and concealed surfaces too.

Do I need a duty level as well as a grade?

In the current AWI casework standard, yes: aesthetic grade and structural duty level are separate, with Custom and level 3 as defaults. The nearest UK idea is a strength and durability test standard, such as BS 6222-2 for kitchen units or EN 16121 for non-domestic storage. There is no mapping between the scales.

Can the studio's partner workshops work to AWI grades?

We do not claim that any partner works to AWI grades or holds any certification to them. The sensible route is to write a quality schedule and ask the partner workshop to confirm in writing what it can deliver and measure, and to approve a control sample.