Visual Grading

Most of our constructional timbers held in stock are pre-graded C16 or C24. When these graded items are cut to length or re-machined the grading status is lost. At EE Olley we have qualified and registered visual graders who can re-grade up to C24 either WET or DRY depending on the moisture content. We can supply C30 graded softwood by special order given economic volumes.

Timber Strength Grading

How is Timber Graded?

Strength grading is needed to ensure timber is strong enough for a particular job, i.e a floor joist or roof truss. It also saves money by helping to avoid over specification. Grading can be carried out visually or by machine.

What do the letters “C” & “D” mean?

The “C” stands for Coniforous for softwood species C14 to C40.
The “D” denotes Desiduous for hardwood species D30 to D70.

What do the strength stamps and grades tell me?

Strength grading is needed to ensure timber is strong enough for a particular job, i.e a floor joist or roof truss. It also saves money by helping to avoid over specification. Grading can be carried out visually or by machine.

 

Visual Strength Grading to C16, C18 & C24

Uses the graders experience & knowledge to assess a parcel of timber by examining: Species, Size & Moisture Content. A unique grade stamp will be applied to the timber batch displaying key data.

Co. LogoGraders numberCertification body ref number
Co. Logo:EEO Graders number:2002/G****:Certification body ref number :1245
Co. Logo:Graders number::Certification body ref number :
Co. Logo:Graders number:BS 4978:Certification body ref number :SS
Co. Logo:Graders number:EN 14081:DRY GRADEDCertification body ref number :C24
Co. Logo:Graders number:British & Euro Standard:Moisture ContentCertification body ref number :Strength grade
Co. Logo:Graders number:WPPA:Certification body ref number :
Co. Logo:Graders number:Species code (WPPA = European Redwood/Whitewood:Certification body ref number :

Strength grading to C27, C30 Available to Order

Strength Classes of Hardwoods

Timbers of similar strength class properties are grouped together into strength classes. These are defined in BS EN338 showing the strength classes D30 to D70.

Common HardwoodStrength Class
Common Hardwood:OakStrength Class:D30 TH1 & THB * see below
Common Hardwood:Oak Strength Class:D40 THA *
Common Hardwood:IrokoStrength Class:D40
Common Hardwood:OpepeStrength Class:D50
Common Hardwood:KeruingStrength Class:D50
Common Hardwood:EkkiStrength Class:D60
Common Hardwood:BalauStrength Class:D70
Common Hardwood:GreenheartStrength Class:D70

Strength Grading of Hardwoods

Visual grading are based on two moisture contents DRY and WET. Five strength classes are defined:

Common HardwoodStrength Class
Common Hardwood:HSStrength Class:Tropical hardwoods
Common Hardwood:TH1 & THBStrength Class:Temperate hardwoods less than 20,000mm2 thickness less than 100mm
Common Hardwood:TH1 & THBStrength Class:Temperate hardwoods 20,000mm2