BM TRADA provides Q-Mark visual strength grading certification to the timber and construction industry.

Recognized grade marking on a piece of timber is its 'Passport' for use in structural applications. 

These standards require that graded material is supplied and marked under the control of a recognized scheme operated by a Certification/Approved Body such as BM TRADA.

Visual grading is carried out by operatives that have successfully passed a process of training and examination supported by annual assessment of continued competency.

About Q-Mark visual strength grading certification

BM TRADA has been providing Q-Mark strength grading certification to the timber and construction industry since the early 1970s. Our experts can advise on product marking including UKCA/UKNI/CE marking. Please contact us to learn more.

Visual strength grading is the process of assessing timbers by reference to a Grading Standard which defines limiting characteristics that can be determined by visual inspection.

These include knot size and position, fissures, distortion, wane, slope of grain, rot/insect damage plus a range of other abnormalities that can affect strength.

There are a number of National Standards for this purpose, such as, BS 4978, BS 5756, INSTA 142, DIN 4074, IS 127, NLGA/NGRDL.

The Standard for controlling Visual Strength Grading operations within UK/ Europe, which is also now being adopted in other countries, is EN 14081-1.

This Standard is supported by various national grading rules:

  • EN 1912 which links the available grades and species to strength classes
  • EN 338 which provides the characteristic values (used by structural engineers) of Visually Strength Graded timber to the Classes C14-C35 for softwoods and D18-D70 for hardwoods.

Visit our certified company list to find suppliers of BM TRADA certified products or services.