Timber Calculator (Gibraltar)

1. Timber conventions in Gibraltar: sizes, grading and where the stock comes from

There is no timber grown or milled in Gibraltar — the Rock has no forestry, so 100% of sawn softwood, hardwood and sheet material arrives by lorry over the border from Spain or by sea/lorry from the UK. In practice this means the timber you can buy locally, or order through a Gibraltar builders’ merchant, is stocked in exactly the sizes UK merchants use: CLS (Canadian Lumber Standard) studwork at 38 mm thickness with eased, rounded edges, and carcassing (regularised sawn) timber at 47 mm thickness for joists, rafters and general framing. Decking boards, typically 28 × 145 mm grooved softwood, follow the same convention.

Structural softwood sold into Gibraltar is graded to BS EN 338, the same British and European standard used throughout the UK, with C16 as the general-purpose structural grade and C24 as the higher-strength grade specified for longer spans or heavier loads. You will see both grades quoted by merchants; C24 typically carries a price premium of 10–20% over C16 for the same section size, reflecting the tighter strength and stiffness sorting. Because the timber is imported rather than locally graded, always ask for grade stamps or a supplier certificate when a structural application requires a specific class — this matters more in a market with no local mill to fall back on for a re-check.

Sizing is always metric here: thickness and width in millimetres, length in metres (2.4 m, 3.0 m, 3.6 m and 4.8 m are the common stock lengths). There is no nominal/dressed-size confusion of the kind you get in North American markets — a "38 × 89" section in Gibraltar is 38 mm × 89 mm, full stop, which is exactly what this calculator assumes (there is no "use actual dimensions" toggle needed because there is only one dimension convention).

Hardwood — oak, iroko, sapele and similar species used for cladding, decking edging, marine fender timbers and joinery — arrives either as sawn, sized stock (priced and measured the same way as softwood, in m³) or, less often but still relevant given the port trade, as round logs bought by length and girth and measured under the traditional hoppus rule. That second case is covered in worked example 2 below.

2. Worked example: a CLS and carcassing cut list, priced in GBP

Say you are framing a stud partition wall and a small floor deck, and your cut list from the merchant’s catalogue looks like this — all standard Gibraltar/UK stock sizes:

• CLS 38 × 89 mm, 2.4 m long — 20 pieces, for stud partitions
• Carcassing 47 × 100 mm, 3.6 m long — 15 pieces, for noggins and minor framing
• Carcassing 47 × 150 mm, 3.6 m long — 8 pieces, for floor joists

1. Convert each section to metres and find the cross-sectional area: 38 × 89 mm = 0.038 m × 0.089 m = 0.003382 m²; 47 × 100 mm = 0.047 m × 0.100 m = 0.0047 m²; 47 × 150 mm = 0.047 m × 0.150 m = 0.00705 m².
2. Multiply each cross-section by its length to get the volume of one piece: CLS 38×89×2.4 m = 0.00812 m³; carcassing 47×100×3.6 m = 0.01692 m³; carcassing 47×150×3.6 m = 0.02538 m³.
3. Multiply each piece volume by quantity: 0.00812 × 20 = 0.1623 m³; 0.01692 × 15 = 0.2538 m³; 0.02538 × 8 = 0.2030 m³.
4. Add the three lines together for the raw cut-list volume: 0.1623 + 0.2538 + 0.2030 = 0.619 m³.
5. Add a waste allowance for offcuts, mis-cuts and rejects — 10% is the standard carpentry rule of thumb, and it is the calculator’s default: 0.619 m³ × 1.10 ≈ 0.681 m³ total to order.
6. Price it: at a typical carcassing/CLS softwood rate of around £350 per m³ (C16, delivered Gibraltar), 0.681 m³ × £350 ≈ £238 for the whole list, including the waste margin. At the higher C24 rate of roughly £400–£420/m³ the same list comes to about £272–£286.

3. Worked example: the hoppus foot method for a round hardwood log

The hoppus rule is not used for sawn softwood in Gibraltar — that is always m³. It survives specifically for round, unsquared hardwood logs, which still turn up in the local trade because of Gibraltar’s port and dockyard history: fender timbers, mooring piles, and imported tropical hardwood logs bought whole before conversion are traditionally quoted by length and girth, using the same hoppus convention UK and Commonwealth timber merchants have used for two centuries. If your log is already sawn to a square or rectangular section, use m³ (or the Huber rule for a round but already-milled log); reach for hoppus only when you are buying or quoting a genuinely round, unconverted log by girth.

The hoppus formula is: hoppus feet = (quarter-girth in feet)² × length in feet, where "girth" means the circumference measured with a tape around the log, not the diameter. Squaring the quarter-girth deliberately estimates the volume of usable squared timber that can be sawn from the round log — discarding the curved outer wane — rather than the true round (cylindrical) volume, which is why a hoppus foot measures noticeably less than a true cubic foot of the same log.

Worked example: a round hardwood log measures 1.2 m in girth (circumference) and 4 m in length.

1. Convert to feet: girth = 1.2 m × 3.28084 = 3.937 ft; length = 4 m × 3.28084 = 13.123 ft.
2. Take a quarter of the girth: 3.937 ft ÷ 4 = 0.984 ft.
3. Square the quarter-girth and multiply by length: 0.984² × 13.123 ≈ 12.71 hoppus feet.
4. Convert to true cubic feet if needed, using 1 hoppus foot ≈ 1.273 true ft³: 12.71 × 1.273 ≈ 16.18 ft³.
5. Convert to cubic metres (1 ft³ = 0.0283168 m³): 16.18 ft³ × 0.0283168 ≈ 0.458 m³ of true round volume — though the log is bought and sold as "12.71 hoppus feet", not as 0.458 m³.
6. Price it: imported hardwood logs of this kind typically run £800–£1,000 per true m³ landed in Gibraltar depending on species and origin; at £900/m³ that works out to roughly £412 for this one log (0.458 m³ × £900).

4. Quick conversion table: m³, board feet, hoppus feet and cubic feet

• 1 m³ = 423.776 board feet (board foot = 144 in³, the North American sawn-timber unit)
• 1 m³ = 35.3147 cubic feet (ft³)
• 1 board foot = 0.0023597 m³ (roughly 2.36 litres)
• 1 hoppus foot ≈ 1.273 true cubic feet ≈ 0.03605 m³
• 1 hoppus ton = 50 hoppus feet ≈ 63.65 true ft³ ≈ 1.802 m³
• 1 true cubic foot ≈ 0.7854 hoppus feet (the hoppus/true ratio comes from squaring a round log’s quarter-girth, which discards the curved waste wood)
• To go from hoppus feet to m³ directly: hoppus ft × 1.273 × 0.0283168 ≈ hoppus ft × 0.03605

5. How timber is actually priced and imported in Gibraltar

Almost all sawn softwood reaching Gibraltar merchants originates as Northern European (Scandinavian, Baltic or occasionally UK-grown) spruce or pine, kiln-dried and machined to CLS or carcassing sizes either in the UK before onward shipment, or in Spain for stock that comes across the border by lorry. Typical 2026 landed prices for general carcassing/CLS softwood sit around £320–£380 per m³ for C16, and £380–£450 per m³ for C24, with decking boards priced somewhat higher per m³ because of the extra machining (grooving, chamfering) — commonly £450–£600/m³ equivalent when bought as finished decking boards rather than raw sawn stock.

Because everything crosses either the Strait (from the UK, usually via consolidated sea freight to Algeciras or direct to Gibraltar) or the land frontier (from Spanish merchants around Algeciras/La Línea/San Roque), freight and handling add a real, variable cost on top of the UK mill-gate price — often in the region of 8–15% for UK-sourced material once you account for consolidation, cross-border handling and the final short haul into Gibraltar, and typically less for Spanish-sourced softwood given the shorter, purely road-based journey. Buyers who can order full pallet or container loads generally get noticeably better per-m³ pricing than those buying small quantities as needed, so it is worth sizing a full project’s cut list (as in worked example 1) before ordering, rather than making several small top-up purchases.

Hardwood — oak, sapele, iroko, and marine-grade species used around the port — is priced separately and substantially higher, commonly £700–£1,200+ per m³ depending on species, with tropical hardwoods for fender or mooring applications often at the top of that range or priced per log by negotiation using the hoppus measure described above. Sheet materials (WBP plywood, OSB) are usually quoted per sheet rather than per m³, but can be converted to a m³-equivalent rate for comparison against sawn stock if you know the sheet thickness.

Prices move with the exchange rate (most underlying stock is priced in euros at origin even when sold in Gibraltar in pounds), with UK and European softwood futures, and seasonally — expect a premium in the run-up to summer when construction and refurbishment activity picks up across the Rock and neighbouring Costa del Sol.

6. Local specifics: import reliance, typical uses and buying tips

Gibraltar’s construction sector — driven by high-density residential development, MOD and dockyard-related works, and ongoing commercial fit-out — is the main consumer of carcassing and CLS timber, almost all of it going into stud partitions, minor roof and floor framing, and formwork rather than large-scale primary structure (steel and concrete dominate structural framing on the Rock). Decking timber sees strong demand for the balconies and terraces typical of Gibraltar’s apartment stock, and marine-grade and hardwood timber has a genuine niche use around the port, dockyard and marina facilities — fendering, walkways, and repair timbers for vessels and pontoons, which is where the hoppus log rule still earns its keep locally.

Because there is no local mill or timber yard producing stock to order, lead times matter more here than in the UK: always confirm whether a merchant is quoting from stock already on the Rock or from a delivery still to come across the border or by sea, and build in a buffer for a specific grade, length or hardwood species that is not sitting on the yard shelf. It is also worth double-checking grade paperwork on structural stock (C16 vs C24) since there is no local testing body to fall back on if a delivery is under-graded.

Buying tips: always price a full cut list in m³ rather than piece-by-piece where possible, since merchants’ per-m³ rates usually improve with volume; ask whether a quote is ex-works Spain/UK or delivered Gibraltar, since freight can be 8–15% of the total; and for any round hardwood log purchase, insist on the girth and length being measured and recorded at the point of sale so the hoppus-foot calculation (and therefore the price) is not disputed later.