There are 12 strength grades as set by the British Standard in the BS 5268, but the most commonly specified are C16 and C24.
Both grades are used in structural applications and are suited to different loads. They can be used for rafters, floor joists, studwork for partition walls, formwork, shuttering etc…
Most imported graded carcassing timber these days tends to be heavy to C24 grade.
Whilst C16 graded timber is strong enough for some applications such as wall plates, studwork, rafters, joists etc…C24 comes with added benefits.
C24 timber has been graded to a higher standard than C16. It’s a premium piece of timber that can handle higher loads and wider spans.
C24 grade can only be achieved by importing timber from areas where the climate forces a slower growth rate and hence a tighter grain.
All Elliotts branches stock C24 graded carcassing as standard.
Yes. If it’s re-sawn in its cross-section or thickness, then its strength grade could be lost. Both pieces of timber will need re-grading before they can be used.
Don’t use it. All graded timber will have a C16 or a C24 grade stamp on the face of the timber.
All Elliotts graded timber is kiln-dried and then pressure treated against insect and fungal attack.
| Thickness | Width | Grading | Treated |
| 100mm | 100mm | C24 Grade | Yes |
| 75mm |
100mm 150mm 200mm 225mm |
C24 Grade | Yes |
| 47mm |
50mm 75mm 100mm 125mm 150mm 175mm 200mm 225mm 250mm |
C24 Grade Except 47 x 500mm and 47 x 75mm |
Yes |
| 22mm |
75mm 100mm 150mm 200mm |
Ungraded |
Yes |
Or speak to Bob Tee for help with your timber project.
