Structural Grading for Oak

All residential and commercial property builds need Building Regulations approval, if structural Oak beams are used in the building they will need to be graded to BS5756 standards and CE certification issued to gain this approval.

BS5756 sets out the guidelines for visual grading of structural timber and the structural grades associated with each visual standard.

  • THa and THb are the visual grades applied to larger section beams, over 20,000mm2 or 100mm thick
  • TH1 and TH2 are the visual grades applied to smaller section beams, under 20,000mm2 or 100mm thick

The only structural grades that can be applied to Oak are D40, D30 and Fail. It does not matter that an individual piece of Oak may achieve a much higher grade, the highest it can be certified for is D40.

  • THa and TH1 will achieve a D40 grade
  • THb and TH2 will achieve a D30 grade

But remember, Oak must be wet graded, dry grading requires a maximum moisture content of 20%, which Oak over 150mm thick will never achieve.

Timberpride has a TRADA trained grader who can inspect and issue CE declaration of performance certification with your order. One less thing to worry about. Please call us on 01666 504 436 for more information.


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“Timberpride provided an excellent service, combining a friendly approach with obvious expertise. They were able to advise on products & met our requirements at a competitive price.”

Debbie Chard – Obvious Expertise

“We have used Timberpride on many occasions, they can get what we need in whatever size we need it, which many timber suppliers fail to do. We highly recommend them.”

Shaun – Highly Recommended

“I had the pleasure of dealing with your company on Friday when I was trying to locate two small pieces of oak for decorative purposes. Whilst I imagine in the grand scheme of things, this was a small order, the help and customer support I got from your colleague Sarah was tremendous, even arranging for the wood to be left at an alternative location for collection to suit me. I would like to pass on my thanks, it was a pleasure to deal with such a customer driven business.”

Dawn Wilson – Tremendous Customer Service

“Just a quick thank you to you and your team for the quick turnaround on the oak that was supplied. The timber was just as requested and was of a good quality. We will be using you again soon. Many thanks.”

Paul Large – Quick Turnaround

I found Timberpride very helpful with the design of my garden room.  The construction was very good, we were impressed.  I would like to thank all of the operatives for a very professional service throughout. Stevenson Building Contractors

Terry Stevenson – Helpful & Professional

"I just wanted to say a big thank you for all your help with designing and delivering on time the lovely oak A-frame for my coach house. Everything went extremely well and to plan, including personal delivery of some of the oak from Alec, the owner and his son. In this day and age of online sales and aggressive pricing it's a great experience to be able to walk into your lovely oak offices, meet the owner, take a look behind the scenes and at your oak waiting to be hand crafted into your designs. It's a true Cotswold experience and well worth the small premium for the excellent service and to be able to engage first hand with all the processes." Bob Davison

A true Cotswold experience and well worth a small premium for the excellent service

Get in touch

Please contact us if you have any questions regarding graded structural oak