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. Logo | Graders number | Certification 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 GRADED | Certification body ref number :C24 |
| Co. Logo: | Graders number:British & Euro Standard | :Moisture Content | Certification 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 Hardwood | Strength Class |
|---|---|
| Common Hardwood:Oak | Strength Class:D30 TH1 & THB * see below |
| Common Hardwood:Oak | Strength Class:D40 THA * |
| Common Hardwood:Iroko | Strength Class:D40 |
| Common Hardwood:Opepe | Strength Class:D50 |
| Common Hardwood:Keruing | Strength Class:D50 |
| Common Hardwood:Ekki | Strength Class:D60 |
| Common Hardwood:Balau | Strength Class:D70 |
| Common Hardwood:Greenheart | Strength Class:D70 |
Strength Grading of Hardwoods
Visual grading are based on two moisture contents DRY and WET. Five strength classes are defined:
| Common Hardwood | Strength Class |
|---|---|
| Common Hardwood:HS | Strength Class:Tropical hardwoods |
| Common Hardwood:TH1 & THB | Strength Class:Temperate hardwoods less than 20,000mm2 thickness less than 100mm |
| Common Hardwood:TH1 & THB | Strength Class:Temperate hardwoods 20,000mm2 |