When you need timber in any quantity for a renovation, a dedicated timber merchant or timber yard will almost always serve you better than a general DIY shed. Stock is deeper, quality is more consistent, and once you have a trade account the price difference is significant. This guide explains how timber merchants work, what they carry, and how to get the best deal whether you’re a contractor or a self-builder.

Timber Merchant vs Builders’ Merchant

Both stock timber, but the emphasis is different. A general builders’ merchant (Travis Perkins, Jewson, Buildbase, MKM) carries timber alongside plasterboard, cement, drainage, and hundreds of other product lines. A specialist timber merchant or timber yard focuses almost exclusively on wood, which means:

  • Wider species and grade selection, structural C16/C24 softwood, European redwood, hardwoods, and specialist joinery sections
  • Longer lengths, typically up to 6 m or even 7.2 m as standard, versus the 4.8 m often maxed out at a general merchant
  • Tighter moisture content control, many timber yards carry kiln-dried stock properly labelled with MC percentages
  • Machining and processing, most timber yards will rip, cross-cut, plane, and rebate to your spec on-site

General builders’ merchants are more convenient for mixed loads (timber + fixings + cement in one delivery), but if timber is the main event, a specialist yard normally wins on price and choice.

FactorSpecialist Timber MerchantGeneral Builders’ Merchant
Species rangeWide (softwood + hardwoods)Mainly structural softwood
Max length (common)Up to 7.2 mUsually 4.8–5.4 m
Sheet materialsFull range + large-formatStandard range
Machining/processingUsually availableRarely
Trade account termsMonthly credit usualMonthly credit usual
Convenience (mixed loads)LowHigh

Sawn vs Planed (PAR) Timber

Structural timber, floor joists, rafters, studwork, is almost always supplied sawn (rough-sawn or regularised, and stamped with a strength class such as C16 or C24). Sawn sizes are nominal: a “50 × 100” piece actually measures close to those dimensions because it hasn’t been finished. Sawn timber is cheaper and perfectly adequate for hidden structural work.

PAR (Planed All Round; some merchants sell similar stock as PSE, planed square edge) is finished to a precise finished size. A nominal 50 × 100 PAR piece will typically finish at around 44 × 94 mm.1 PAR usually costs more per linear metre than sawn equivalents but is essential for joinery, carcassing, architraves, skirtings, and anything that will be seen or need a tight fit.

When ordering, always confirm whether your quoted size is nominal (sawn) or finished (planed), because the difference of a few millimetres matters in joinery work.

What the Grade Stamp Means

C16 and C24 are strength classes from BS EN 338, the standard that fixes the characteristic strength, stiffness and density values a designer works to, and it covers softwoods and hardwoods within the scope of BS EN 14081-1.2 They are not the same thing as the visual grades GS (General Structural) and SS (Special Structural) in BS 4978, which set the permitted knots, wane, slope of grain and distortion.3 Which strength class a GS or SS piece lands in depends on its species and source, and is assigned through BS EN 1912, current in its 2024 edition.4 The marking rules in BS EN 14081-1 are what make the stamp on a joist mean anything, so if structural timber arrives without a grade stamp, ask the merchant how it has been marked.5 CLS, meanwhile, is a description of size and finish (planed, with rounded arrises), not a grade.6

Sheet Materials

Most timber merchants stock a full range of sheet materials alongside dimensional timber:

  • OSB (Oriented Strand Board), OSB2 and OSB3, both load-bearing boards under BS EN 300; the difference is service condition, OSB2 for dry conditions and OSB3 for humid ones, which is why roofs, floors and sarking are specified in OSB378
  • Plywood, structural (C/C or C/D grade), hardwood-faced, marine, and birch-faced ply
  • MDF, standard, moisture-resistant (MR MDF), and fire-rated grades
  • Chipboard, flooring-grade tongue-and-groove P5, which is BS EN 312’s load-bearing board for humid conditions9
  • Cement particle board / Fermacell, often stocked at specialist merchants

Sheet prices vary substantially with global commodity markets. As a rough guide, trade pricing on an 18 mm OSB3 sheet (2440 × 1220 mm) is often below typical DIY-shed retail, so it is worth comparing. The saving per sheet may seem modest, but across a whole roof or floor it adds up quickly.

Large-format sheets (up to 3050 × 1525 mm) are available from specialist merchants and some larger builders’ merchants, useful for worktops, interior joinery, and reducing waste on large spans.10

Machining and Processing Services

One of the biggest advantages of a specialist timber merchant over a DIY retailer is on-site machining. Most yards offer:

  • Cross-cutting to exact length (often charged per cut, with the price depending on section size)
  • Ripping to width on a band-saw or table saw
  • Planing and thicknessing, converting sawn to a specific finished size
  • Rebating and moulding, profiles for architraves, glazing beads, door stops

This means you can often order, say, 44 mm thick oak boards and have them thicknessed and ripped to the exact width your job demands. The cost of machining is usually far lower than the waste you’d generate cutting down oversized sections yourself, and it saves van space on the way to site.

Always ask about machining lead time when ordering, a straightforward cut to length can be done while you wait, but profiling or moulding may add a day or two.

Ordering and Delivery

Measuring accurately is your most important job before calling a timber yard. Order by linear metres for dimensional timber and by sheet count for boards. Quote species, grade, section size (nominal or finished), and length. A good merchant will query anything ambiguous.

Delivery is available from most timber yards via flatbed or HIAB lorry. Delivery is commonly free above a minimum order value and charged as a flat fee below it, within a local radius. Champion Timber, a London-area timber merchant, for example delivers free on stock orders over £150 ex VAT and charges £25 below that.11 For structural timber deliveries, confirm:

  • Whether an offload is included (HIAB) or you need labourers on site
  • The lorry length and access width, long timber loads need clear road access
  • Lead time, common sizes are often same-day or next-day; less common sections may need 3–7 days

Returns: unlike tiles or bricks, timber cut to length is generally non-returnable. Order a modest contingency (typically 5–10% extra for wastage and cutting) but avoid over-ordering significantly.

Costs and Getting Trade Pricing

Walk-in pricing at a timber yard is often below a DIY chain like B&Q or Wickes for equivalent structural products, though it is worth checking item by item. Opening a trade account usually brings a further discount off the walk-in rate, with the size of it depending on your monthly spend.

To open a trade account at most timber merchants, you’ll need:

  • A registered business name, sole-trader details, or a consistent billing address
  • Credit references (often 2–3 trade references from existing suppliers)
  • A typical spend estimate, higher anticipated volume means better rates from the outset

Credit terms are usually monthly: Travis Perkins, for example, asks for payment at the end of the month following the invoice date.12

If you’re a homeowner doing a single project, most timber yards will still serve you at walk-in rates without an account. Being clear about the total quantity needed and asking politely whether there’s a project discount often yields a small reduction.

Comparing quotes: for significant timber packages, say, a loft conversion or extension, it’s worth getting priced by at least two or three suppliers. Provide identical specification lists so quotes are comparable. Merchants will often sharpen their price if they know they’re competing.

Timber is standard-rated, so VAT is charged at 20%, the standard rate since 4 January 2011.1314 Trade accounts are usually quoted ex-VAT; make sure you’re comparing like-for-like when reviewing quotes from different suppliers.

References (14)

Figures in this note were checked against the sources below on 2 October 2026. Superscript numbers in the text point to them. Every source the site cites, by topic.

  1. 1technicalsupplier figureSelco Builders Warehouse, guidance.RN-I9Y9BAA national builders' merchant's product page for nominal 100 x 50 mm planed redwood. It settles that the finished planed size is about 94 x 44 mm.
  2. 2technicalstrongBSI, a standard.RN-TBEMIMBS EN 338:2016, published 30 June 2016, committee B/518, ISBN 978 0 580 83526 1, current; it supersedes BS EN 338:2009. Clause 1 establishes the system of strength classes for general use in design codes, giving characteristic strength and stiffness properties and density values for each class, to which EN 14081-1 refers. It applies to all softwood and hardwood timber for structural use within the scope of EN 14081-1. This is the standard that defines C16 and C24, the two softwood classes a merchant sells joists in, along with the C and D class series generally. Clause 5 is the classification of structural timber and clause 6 covers allocation of a population to a strength class by visual grading or machine grading. Cite it whenever a note says a joist is C16 or C24, since the letter and number are a graded characteristic strength, not a species or a quality label.
  3. 3technicalstrongBSI (British Standards Institution), a standard.RN-QWYQ8TSTATUS: CURRENT. BS 4978:2007+A2:2017 was published 30 November 2017 and is the live edition, superseding BS 4978:2007+A1:2011, BS 4978:2007 and the older BS 4978:1988 Specification for softwood grades for structural use. It specifies the methodology for visual strength grading of softwood for structural use and sets the permissible limits of characteristics (knots, slope of grain, fissures, wane, distortion, rate of growth) for two visual grades: GS (General Structural) and SS (Special Structural). These are grades, not strength classes: the strength class a graded piece maps to (C16, C24 and so on) depends on species and is assigned via BS EN 1912 and BS EN 338, so a note saying a timber is graded C24 to BS 4978 is conflating the two. The catalogue page confirms number, title, date, status and grades; the limit tables are paywalled.
  4. 4technicalstrongBSI Knowledge, a standard.RN-KN61DNBS EN 1912:2024, published 31 May 2024, status current on the BSI catalogue (withdrawnAt: not-withdrawn, validity: current). It is the missing link between a visual grade stamp and a strength class: clause 1 states that the standard lists the visual strength grades, species and sources of timber and specifies the strength classes to which they are assigned, as documented in EN 338, with clause 6 being the assignments to strength classes. It supersedes BS EN 1912:2012 (published 31 August 2012, withdrawn 30 May 2024), which in turn superseded BS EN 1912:2004+A4:2010; the species and source lists change between editions, so a note quoting a grade-to-class mapping needs the 2024 edition. Use it alongside BS 4978 (GS and SS grades) and BS EN 338 (what C16 and C24 mean); the marking itself is made under BS EN 14081-1.
  5. 5technicalstrongBSI (British Standards Institution), a standard.RN-TXD8LASTATUS: CURRENT, and it is the replacement for the withdrawn BS EN 519. BS EN 14081-1:2016+A1:2019 was published 31 August 2019, ISBN 978 0 539 06 228 1, and supersedes BS EN 14081-1:2016. It sets the requirements for strength graded structural timber of rectangular cross section produced by sawing, planing or similar, covering BOTH visually and machine graded timber, and it gives the test methods, the Assessment and Verification of Constancy of Performance and the marking rules, which is what makes a C16 or C24 stamp on a joist meaningful. It excludes fire retardant treated timber, thermally or chemically modified timber and structural finger jointed timber. Parts 2 and 3 add machine grading type testing and factory production control. Cite this with BS 4978 (visual grading rules), BS EN 338 (strength classes) and BS EN 1912 (assignment of grade and species to class). Catalogue page confirms number, title, date, status, supersession and scope.
  6. 6technicalsupplier figureTravis Perkins, guidance.RN-DNWJ6LA national builders' merchant's product page for 38 x 89 mm CLS studwork timber. It settles that CLS is regularised by planing all round with eased, rounded corners, a size and finish description separate from its strength class.
  7. 7technicalsupplier figureWest Fraser, guidance.RN-COWMQ0A UK OSB maker's FAQ, confirming OSB3 to EN 300 is certified for load-bearing use in humid conditions.
  8. 8technicalstrongBSI, a standard.RN-G4ZRB1BS EN 300:2006, published 31 August 2006, committee B/541, current; it supersedes BS EN 300:1997. Clause 1 states it applies to oriented strand boards, defines the terms, establishes a classification and specifies the requirements, with clause 4 being the classification of boards and clause 5 the general requirements for all OSB types. It states plainly that the values it lists relate to product properties and are not characteristic values to be used in design calculations: test methods for mechanical properties for structural purposes are in EN 789, determination of characteristic values and density for structural purposes in EN 1058, and design characteristic values for OSB in EN 12369-1, with supplementary properties in Annex C. This is the standard that a board marked OSB3 is classified against, so cite it whenever a note specifies OSB for a floor deck.
  9. 9technicalstrongBSI, a standard.RN-DNW09XBS EN 312:2010, published 30 November 2010, committee B/541, under review; it supersedes BS EN 312:2003 and the earlier seven-part series BS EN 312-1 to -7, whose part titles are still visible in the BSI catalogue and name the board categories directly: general purpose boards for use in dry conditions, boards for interior fitments including furniture for use in dry conditions, load-bearing boards for use in dry conditions, load-bearing boards for use in humid conditions, and heavy-duty load-bearing boards for dry and for humid conditions. Clause 1 of the 2010 edition specifies the requirements for flat-pressed or calendar-pressed unfaced particleboards as defined in EN 309, and it is called up in EN 13986 for construction applications where these are referred to as resin-bonded particleboards. It warns the values it lists are product properties and are not characteristic values for design calculations, which come from EN 12369-1 or from testing to EN 789, EN 1058 and ENV 1156. This is the standard behind a chipboard flooring panel grade.
  10. 10technicalsupplier figureChampion Timber, guidance.RN-UOQUEJA timber merchant's product page for an 18 mm MDF board in the large 3050 x 1525 mm format. It settles that large-format sheets of this size are stocked by specialist timber merchants.
  11. 11costsupplier figureChampion Timber.RN-1P3GWFA price, true at 2026-09. A timber merchant's delivery terms page. It settles free next-day local delivery on stock orders over £150 ex VAT and a £25 delivery charge below that value.
  12. 12technicalsupplier figureTravis Perkins Trading Company Limited, guidance.RN-CP9ZSUTravis Perkins' own credit account application form and terms. It settles that its credit terms require payment by the end of the month following the date of invoice.
  13. 13technicalvery strongThe National Archives (legislation.gov.uk), guidance.RN-0CTUS1The Act that raised the standard rate of VAT from 17.5 per cent to 20 per cent. It settles that the 20 per cent rate applies to supplies made on or after 4 January 2011.
  14. 14technicalvery strongHM Revenue & Customs (GOV.UK), guidance.RN-4W7T33Sets the three UK VAT rates: standard 20% on most goods and services, reduced 5% on some goods and services such as children's car seats and home energy, and zero 0% on zero-rated goods such as most food and children's clothes. The standard rate rose to 20% on 4 January 2011 from 17.5%. Some supplies are exempt rather than rated, including postage stamps and financial and property transactions. This is the reference for converting a merchant's ex-VAT trade quote into the figure a homeowner actually pays.

  1. PAR Redwood 100 x 50mm (4” x 2”) PTL NOM PEFC, Selco Builders Warehouse, accessed 2 October 2026. selcobw.com

  2. BS EN 338:2016 Structural timber. Strength classes, BSI Knowledge, accessed 9 September 2026. knowledge.bsigroup.com

  3. BS 4978:2007+A2:2017 Visual strength grading of softwood. Specification, BSI Knowledge, accessed 9 September 2026. knowledge.bsigroup.com

  4. BS EN 1912:2024 Structural Timber. Strength classes. Assignment of visual grades and species, BSI Knowledge, accessed 9 September 2026. knowledge.bsigroup.com

  5. BS EN 14081-1:2016+A1:2019 Timber structures. Strength graded structural timber with rectangular cross section. General requirements, BSI Knowledge, accessed 9 September 2026. knowledge.bsigroup.com

  6. 38mm x 89mm x 3m CLS Profile Kiln Dried Studwork Timber, Travis Perkins, accessed 2 October 2026. travisperkins.co.uk

  7. Frequently Asked Questions, West Fraser, accessed 30 September 2026. uk.westfraser.com

  8. BS EN 300:2006 Oriented strand boards (OSB). Definitions, classification and specifications, BSI Knowledge, accessed 9 September 2026. knowledge.bsigroup.com

  9. BS EN 312:2010 Particleboards. Specifications, BSI Knowledge, accessed 9 September 2026. knowledge.bsigroup.com

  10. 3050 x 1525 x 18mm MDF Board, Champion Timber, accessed 2 October 2026. championtimber.com

  11. Delivery, Champion Timber, accessed 2 October 2026. Priced at 2026-09 and left there. championtimber.com

  12. Credit Account Application Form, Travis Perkins Trading Company Limited, accessed 30 September 2026. prod1-tp01-prod02-aws-travisperkins-com-public.s3.amazonaws.com

  13. Finance (No. 2) Act 2010, section 3: Rate of value added tax, legislation.gov.uk, accessed 2 October 2026. legislation.gov.uk

  14. VAT rates, HM Revenue & Customs (GOV.UK), accessed 9 September 2026. gov.uk