Designing to standard sizes: sheet, board and timber

At a glance

Sizes are typical figures from merchant pages and manufacturer data sheets read on 5 November 2026, not what any partner workshop stocks. Ask the maker which formats it holds. 2440 x 1220 mm is 8 x 4 ft and about 2.98 m².

Typical stock sizes

‘Standard’ is a habit of the trade, not a rule: boards come in the sizes that mills press and merchants stock. The table lists what we could read. Treat every figure as typical: merchants stock the common format (2440 x 1220 mm, which is 8 x 4 ft) and order the rest, and a maker may buy from a different mill. Standards govern the tolerances: the data sheets we read cite EN 622 parts 1 and 5 for MDF and EN 312 and EN 14322 for melamine-faced chipboard, which we have not read, so confirm against the current editions.

Typical figures, not a promise of supply. One manufacturer data sheet gives a length and width tolerance of ±5 mm and a sanded thickness tolerance of ±0.3 mm for melamine-faced chipboard: the next section uses the ±5 mm as an example, and yours may differ. See also MDF decoded and veneer specification.

What a 10 mm change does: a cut plan

Take twenty doors, each 600 mm wide, to be cut from 2,440 x 1,220 mm board. Allow [5] mm of trim at each edge of the sheet and [3] mm for each saw cut: example values, because the partner workshop’s own practice governs. The usable board is then 2,430 x 1,210 mm.

• Door 1,210 mm high. Two fit end to end along the length (2 x 1,210 + 3 = 2,423, within 2,430) and two fit across the width (2 x 600 + 3 = 1,203, within 1,210). That is four doors a sheet, so twenty doors need five sheets.
• Door 1,220 mm high. Two no longer fit end to end (2 x 1,220 + 3 = 2,443, more than 2,430), and a door cannot turn across the width (1,220 is more than 1,210). That is two doors a sheet, so twenty doors need ten sheets.

A 10 mm change doubled the boards. The offcut in plan B is not wasted if other parts fit it, and the plan counts doors only: a real cutting list mixes parts, and a good cutter nests them. Treat this as the clean case that shows the mechanism, not a forecast of wastage on a real job. The step also depends on trim and on the sheet itself:

Tallest part of which two fit end to end along a 2,440 mm sheet, with a [3] mm saw cut between them. Even the 1,210 mm door in the example has a margin of only 1 mm when the sheet is 5 mm short and the trim is [5] mm, so drawing to the limit is risky: 1,200 mm leaves room. The ±5 mm is the figure from one chipboard data sheet.

Dimensions that nest, and lengths that do not

Work from the board backwards. The table gives the largest equal part when a usable length is cut into n parts with a [3] mm saw cut between them (rounded down to the millimetre). Trim of [5] mm at each edge is already taken off. A drawn part at or under the figure nests; a part a few mm over it takes the next row down.

Example: three parts end to end along a 2,440 mm board can each be up to 808 mm long, and two can each be up to 1,213 mm. Across the 1,220 mm width, two parts can each be up to 603 mm wide.

The same arithmetic explains long panels. A panel 600 mm wide goes two to a sheet across a 1,220 mm board, and the question is how much of the sheet it uses. The table uses the long MDF formats from one manufacturer data sheet (2,745 and 3,050 long). They are ordered formats, not merchant stock, so confirm availability and any minimum quantity with the partner workshop.

Share of the full sheet used = panels per sheet x length x 600 ÷ (stock length x 1,220). A 2,400 mm panel uses 96.7% of its sheet; at 2,440 mm it needs the next length up and uses 87.4%; at 2,700 mm it is back to 96.7%. The worst lengths are just over a stock length.

Solid timber: nominal, sawn and finished

Timber is bought by a nominal section and used at a smaller finished one. The sources we read give examples, not a rule:

The practical lesson is to draw and specify finished sizes and to say so, and to ask the maker which finished sections it can get from stock without buying the next size up and planing the difference away. We found no UK table of sawn hardwood thicknesses to publish, so none is given: the maker or merchant will supply its own sawn-to-finished sizes.

Design rules, and when to break them

• Start from the usable board, not the sheet. Take off trim, count saw cuts, then choose sizes that divide what is left.
• Leave a margin. A part drawn to the exact limit fails when a sheet comes in short. Draw a little under.
• Keep a family of sizes. A few door heights and widths, repeated, leave offcuts that other parts can use.
• Check the grain. Veneered and decor boards have a direction. Turning a part to nest breaks the grain, so ask the maker which parts may turn.
• State finished sizes after planing, sanding, veneering and edge banding, and ask the maker for its cutting plan before drawings are approved.
• Break the rule when the design needs it. A non-standard size is a design decision, not a mistake. Ask for the as-drawn price beside the standard-size alternative, as our pricing page describes, so the design team chooses what changes. Our How We Work page lists sizes that suit standard freight and the building’s lift among the ways a package can flex.

Parts are designed to fit [2,440 x 1,220] mm board, allowing [5] mm trim at each edge and [3] mm per saw cut. The maker is to confirm the board formats it holds and the cutting plan for [item] before drawings are approved. Dimensions marked [flex] may change by up to [10] mm, by agreement with the designer, to improve the yield.

All sizes on drawings and schedules are finished sizes, after planing, sanding, veneering and edge banding. Timber sections are stated as finished sections. The maker is to state the sawn size it will buy for each section.

Panels longer than [2,400] mm are shown on the shop drawings with the board format they are cut from. A change that moves a panel past a stock length needs the designer's written approval, because it changes the board used.

Standards and sources

• MDF manufacturer product data sheet (edition V 4/15): board formats and thicknesses; cites EN 622 parts 1 and 5 (read as a hosted copy, 5 Nov 2026; check the maker's current sheet).
• Melamine-faced chipboard manufacturer technical data sheet (Rev. 5, 7 Nov 2022): delivery dimensions and tolerances; cites EN 312 and EN 14322 (read 5 Nov 2026; the standards themselves not read).
• UK merchant listings, read 5 Nov 2026: MDF, pre-veneered MDF and birch plywood sizes, planed softwood and rough sawn oak guidance. Typical figures only; the merchants are named in our working notes.
• Make Bespoke Studio journal: How to specify bespoke joinery: what a joinery specification should state.

Questions we are asked

What are the standard sheet sizes for MDF, plywood and chipboard in the UK?

Typical full sheets we read are 2440 x 1220 mm (8 x 4 ft) for MDF, pre-veneered MDF and birch plywood, and 2800 x 2070 mm for melamine-faced chipboard. Longer or wider formats exist but are usually ordered: one manufacturer lists MDF up to 3050 mm long, and one merchant gets 3050 x 1525 mm plywood on special order. These are typical figures, not what any workshop holds.

How does a non-standard dimension increase waste?

A part that is a few millimetres over a divisor of the board stops a second part fitting beside it. In our example a door 1,210 mm high gives four a sheet, and at 1,220 mm only two: twenty doors need five sheets or ten. The offcut can be used if other parts fit it.

Is the nominal size of timber the same as its finished size?

No. One merchant lists a 22 x 100 mm planed softwood section as 18 x 94 mm finished and says finished sizes are typically 2 to 5 mm smaller than nominal. For rough sawn hardwood, one merchant advises adding 10 to 15 mm to the finished thickness and at least 10 mm to the width. Draw and specify finished sizes, and say so.

How do I design joinery to standard sheet sizes?

Start from the usable board (the sheet less trim), count a saw cut between parts, and choose sizes at or just under what divides evenly: the nesting table does the arithmetic for two board sizes. Keep a short family of repeated sizes, check the grain direction, and ask the maker for its cutting plan before drawings are approved.

Do the partner workshops stock these sizes?

Not confirmed. The figures here come from merchants and manufacturers, not from the partner workshops, so the studio asks each partner which board formats it holds and what trim and saw-cut allowances its cutting plans use before a dimension is fixed.

Should I always design to standard sizes?

No. A non-standard size is a design decision. Ask the maker for the as-drawn price next to the standard-size alternative, and decide with both in front of you. The point of this sheet is to make the choice visible.