What Does "EX" Mean in Timber?

If you’ve ever read a timber cutting list and wondered what “EX” means, you’re not alone. It’s one of those tiny abbreviations that has a big impact on what actually arrives on site—and on whether it fits. In short, “EX” (often written “ex”) stands for “ex sawn size”. It tells you the size of the piece before any machining, planing or ripping takes place. For example, if a board is listed as 125mm × 22mm 2EX, it began life rough sawn at 125mm wide and 22mm thick and is being processed into two pieces from that starting size.

What “EX” really means (and why it matters)

When timber is sawn from the log, the dimensions are “nominal” or “rough sawn”. If the piece is later planed, profiled, or cut down (“ripped”) into multiple narrower strips, its finished size will be smaller than the ex size. That’s the whole point of stating “EX”: it locks in the starting dimensions so everyone understands there will be a reduction during processing.

In fencing and landscaping, this crops up everywhere—from battens and rails to posts and capping. If you’re shopping our timber range, or specific categories like timber battens, square rails, cant rails and panel capping, understanding “EX” makes it easier to choose the right component and plan your clearances.

How to read a line like “125 × 22 2EX”

Let’s decode that common style of note you’ll see on cutting lists and quotes:

• 125mm × 22mm = the ex (rough sawn) width and thickness.
• 2EX = the out-turn is two pieces ripped from that ex size (sometimes noted as “rip 2”).
• Finish = after ripping (and any planing), each piece will be narrower/thinner than the ex size. How much narrower depends on kerf (the saw cut) and whether it’s planed.

Because kerf widths and planing allowances vary, it’s good practice to give yourself a few millimetres of tolerance in designs—especially for tight reveals, slatted screens, and cap-over details.

“EX” vs “PAR”, “PSE”, and “Nominal”: the key differences

Alongside “EX”, you’ll encounter other short codes. Here’s a snapshot of how they compare, so you can sanity-check spec sheets in seconds.

How much smaller is the finished size compared with EX?

There isn’t a single national deduction that fits every mill, species and machine setup—but in garden joinery and fencing you’ll commonly see:

• Planing allowance: expect a reduction of a few millimetres on each planed face. As a rule of thumb, a board ex 22mm often finishes around 19mm after planing; ex 100mm width frequently ends up around the mid-90s when planed.
• Saw kerf: modern rip blades are often around 2–3mm. If you “2EX” a board, allow for one kerf; if you “3EX”, allow for two kerfs, and so on.

When in doubt—especially if you’re building a slatted screen with tight gaps—round your calculations conservatively and check the finished dimensions of any product you’re ordering. For example, if you’re building trellis infills with our 1.83m × 38×16mm Trellis Batten (Brown) or Trellis Batten (Green), plan your spacings with a modest tolerance—your install will go smoother and look sharper.

Worked examples: from EX sizes to what you handle on site

Take these simplified, typical scenarios (always check actual product listings and machining notes):

• EX 125 × 22 2EX into battens: Start from 125mm width; rip into two. Deduct one kerf (say 3mm), leaving ~122mm to share across two pieces—about 61mm each before any planing. If both faces are planed, each finished batten will be slightly under that, depending on the passes taken.
• EX 100 × 100 post, PAR finish: After planing, a “100” square often finishes around “95” (varies by mill). For fencing, posts are usually left sawn; see our robust wooden fence posts and ultra-durable concrete fence posts if you prefer zero maintenance.
• EX 22 capping, PSE finish: Many cappings specified as “ex 22” finish around “19”. For neat, water-shedding tops, browse panel capping in brown and green.

EX and fencing: where you’ll see it most

In the world of garden boundaries, “EX” pops up most often in battens, rails and any bespoke cutting. Three common contexts:

1. Trellis and slatted screening. Many designers specify ex sizes then “2EX” or “3EX” to describe the rip pattern. If you’re building your own, our timber battens are a smart starting point; if you’d rather buy ready-made, choose from trellis panels like horizontal slatted, privacy square, traditional square, diamond lattice and fan trellis.
2. Rails and cappings. Specifications may be given ex size then planed to suit. See square rails, cant rails and capping to finish a run professionally.
3. Posts and structural sections. Posts are generally supplied to nominal sawn sizes (rather than planed). Browse wooden fence posts (75×75 and 100×100) or choose long-life concrete posts if you expect high winds.

Quick conversions: typical outcomes from popular EX sizes

Use this as a light-touch guide when sketching layouts. The exact finished size depends on the mill and machining passes, so treat these as indicative only.

Choosing components: when EX is useful and when finished sizes are better

Use EX when you’re describing how a piece will be created—particularly in joinery, bespoke battens, and workshop orders. Use finished sizes when you’re buying pre-made products or when a dimension must fit into a slot, rebate or cap exactly. Examples from our range:

• Pre-made trellis and slatted panels. Finished widths and heights are set—browse trellis panels like horizontal slatted and privacy square.
• Posts and gravel boards. Generally ordered to nominal sizes, not EX. See wooden posts, concrete gravel boards, wooden gravel boards and the overview gravel boards page.
• Bespoke battens and trims. If you’re cutting your own, “EX” plus “2EX/3EX” tells a machinist exactly what to do. If you’re buying off the shelf, choose finished pieces such as our 38×16 battens to keep things simple.

When “2EX”, “3EX” and friends appear (and what they mean)

Alongside “EX”, you’ll often see a preceding number: 2EX, 3EX, 4EX. In the context of cutting instructions, this indicates the number of out-turn pieces the board will be ripped into. The starting ex width should be large enough to accommodate those pieces plus the saw kerfs. A quick memory jogger:

Design tips: using EX sizes without getting caught out

EX sizes are brilliant for communicating how timber should be processed—but they do mean the on-site, in-hand piece will be smaller. These tips keep builds on track:

• Design to the finished gap, not the batten size. For slatted screens, decide your gap first and then let slat width float by a millimetre or two. It’s visually invisible but gives essential tolerance.
• Leave a little daylight under cappings and rails. If a cap is specified from ex 22, assume a finish around 19 and keep mortices or housings generous.
• Plan movement and drainage. Timber moves across the grain; keep slats off paving and add gravel boards so panels and posts don’t sit in splash zones.
• Pick fixings that bite properly. For ex-to-finish reductions, a slightly shorter screw often gives better control. Our trade tubs—5.0×75mm, 5.0×50mm, 5.0×100mm—cover most jobs.

Where EX doesn’t usually apply in fencing

Plenty of products are simply ordered to nominal sizes, with no extra machining. That includes most posts, a lot of rails, and ready-made panels. If you want maximum longevity with minimal fuss, concrete options are hard to beat: see concrete fence posts and concrete gravel boards. For a warmer look, pair timber posts with wooden gravel boards and finish with matching capping.

Buying checklist: EX and finished sizes

Before you click “add to basket”, run through this quick checklist—especially on mixed projects where you’re combining ready-made panels with site-cut battens or trims.

Real-world combinations that use EX logic

• Designer slatted screen with ready-made posts. Choose 100×100 timber posts and rip battens from ex 125 × 22 stock into “2EX” or “3EX” depending on the rhythm you want. Keep gaps consistent; finish with panel capping.
• Courtyard trellis with gravel-board base. Use concrete gravel boards to keep timber out of splash zones, then mount pre-made slatted trellis panels. If you’re infilling, cut battens from ex width and note “2EX” for clean repetitiveness.
• Gate framing. Pair heavy posts with a decorative gate from garden gates and matching gate posts. Add custom trims ripped “2EX” from ex widths to echo cladding lines.

Common pitfalls when working from EX sizes

• Forgetting kerf. Two rips mean two kerfs—those millimetres add up across a run.
• Designing to ex size instead of finished. Doors, caps and infills should be sized to the piece you’ll hold in your hand, not the piece you started from.
• Mixing planed and sawn without thinking about look. PAR/PSE reads crisper; sawn is more rustic. Keep a consistent finish across visible runs for a professional result.

FAQs about “EX” in timber

Does “EX” mean the actual delivery size?

No—“EX” is the starting size before machining. The delivered, in-hand piece will typically be smaller if it’s been planed and/or ripped.

What does “2EX” specifically tell me?

It indicates two out-turn pieces are to be cut from the ex size. For example, 125 × 22 2EX means one rough-sawn board of 125mm width is ripped into two slats after allowing for the saw kerf and any planing.

How do I allow for planing?

As a rule of thumb in garden joinery, assume a few millimetres off each planed face. If the finished measurement matters (e.g., a slat fitting a routed groove), design to the finished figure rather than the ex size.

Where does “EX” show up in fencing products?

Most standard components are sold to nominal sizes (panels, posts, gravel boards). You’ll mainly encounter “EX” on cutting lists for battens, rails and bespoke trims—handy if you’re custom-building a screen rather than buying a ready-made single slatted panel or double slatted panel.

Is there a standard UK deduction from EX to finished?

No single figure applies to all mills and machines. Expect minor variance. If you need absolute precision for a detail, cut and test a short length first or buy a finished piece sized for the task.

Handy products while you’re here

• Battens for bespoke trellis: 38×16 brown, 38×16 green.
• Ready-made screening: fence-topper trellis, slatted trellis, privacy trellis.
• Posts and bases: timber posts, concrete posts, bolt-down shoes & supports.
• Base protection: concrete gravel boards, wooden gravel boards.
• Finishing touches: panel capping, screws & fixings.
• Sleepers for matching hard-landscaping: railway sleepers.

Putting it all together: a mini spec you can copy

Let’s say you’re creating a slatted privacy panel between two posts with a contemporary, even rhythm. Here’s a simple approach using EX notation plus products you can order today:

1. Set your structure: 3.0m × 100×100 posts on 100mm bolt-down shoes (no digging on slabs), or concrete in with cement products.
2. Protect the base: Add 6" concrete gravel boards or 1.83m timber boards.
3. Specify slats: From ex 125 × 22 stock, note “2EX” to produce two slats per board (allow kerf). Alternatively, use ready-made 38×16 battens for predictable spacing.
4. Fix cleanly: Use exterior screws—5.0×75 for rails to posts, 5.0×50 for battens to rails. Consider a security bracket if lift-out is a concern.
5. Cap and finish: Add panel capping (often ex 22, finishing ~19) for a sleek, water-shedding top line.

The bottom line

“EX” is a small abbreviation that tells a big story: it fixes the starting size of the timber before any machining. Add a prefix like “2EX” or “3EX”, and it also tells you how many pieces you’re ripping from that board. Keep an eye on kerf and planing allowances, design to the finished dimension where it matters, and you’ll avoid the classic headaches of parts that are just a shade too tight—or annoyingly loose.

Ready to get cracking? Pick your framework from wooden fence posts or concrete fence posts, protect the base with gravel boards, and decide whether you’ll rip your own battens from ex sizes—or go straight to finished with our pressure-treated timber battens and ready-made trellis panels. Either way, you’ll have a boundary that looks sharp, lasts, and reads like it’s been designed by a pro.