The Story
C24 structural timber 47mm x 125mm is a stress-graded, regularised section suited to load-bearing construction work including floor joists, rafters, and studwork. Kiln dried to 20% moisture content or less for dimensional stability and compliance with UK building regulations.
Specifications
| Property | Detail |
|---|---|
| Material | Softwood (spruce/pine/fir) |
| Grade | C24, stress graded to BS 4978 |
| Finish | Sawn, regularised (planed to consistent dimensions with eased corners) |
| Nominal Size | 47mm x 125mm |
| Finished Size | Approximately 45mm x 120mm |
| Lengths | 3.6m (12ft), 4.8m (16ft) |
| Treatment | Kiln dried to 20% moisture content or less |
| Profile | Regularised with eased arrises |
What it's used for
- Floor joists in domestic and commercial timber frame construction
- Roof rafters and ridge boards where C24 grade is specified by an engineer or building control
- Studwork in load-bearing timber frame walls
- General structural carcassing where span and load capacity require a higher grade than C16
Fitting and handling
Allow the timber to acclimatise on site for at least 24 to 48 hours before fixing, keeping it stacked flat on bearers off the ground and under cover to prevent moisture uptake. Use galvanised or stainless steel fixings throughout to avoid corrosion staining, and where joist hangers or structural connectors are specified, ensure they are rated for C24 timber. Store any unused lengths flat and supported at regular intervals to prevent bowing.
FAQ
What is the difference between C16 and C24 structural timber?
C24 is a higher stress grade than C16, meaning each piece has been tested and confirmed to carry greater loads over longer spans. It is specified where structural calculations or building control require increased strength, for example in floor joists at wider centres or in roof rafters with longer rafter runs.
What does regularised mean on sawn timber?
Regularised timber has been passed through a planer to bring all pieces to a consistent depth, which makes it easier to achieve level floors and plumb walls without packing. The arrises (corners) are also eased to reduce the risk of splits and splinters during handling. The face and edge remain sawn in appearance rather than fully smooth.
Is this timber suitable for use in a structural floor without further treatment?
For most above-ground internal floor joist applications in a ventilated, dry environment this section can be used without preservative treatment. If the timber will be close to or in contact with masonry, near an external wall, or in a poorly ventilated subfloor void, a preservative-treated section should be considered. Always confirm requirements with your structural engineer or building control officer.
Browse the full range of C24 graded timber at Nottage Timber Merchants. We supply trade and retail customers across South Wales, with next-day delivery available to the Bridgend area and surrounding regions.
Description
C24 structural timber 47mm x 125mm is a stress-graded, regularised section suited to load-bearing construction work including floor joists, rafters, and studwork. Kiln dried to 20% moisture content or less for dimensional stability and compliance with UK building regulations.
Specifications
| Property | Detail |
|---|---|
| Material | Softwood (spruce/pine/fir) |
| Grade | C24, stress graded to BS 4978 |
| Finish | Sawn, regularised (planed to consistent dimensions with eased corners) |
| Nominal Size | 47mm x 125mm |
| Finished Size | Approximately 45mm x 120mm |
| Lengths | 3.6m (12ft), 4.8m (16ft) |
| Treatment | Kiln dried to 20% moisture content or less |
| Profile | Regularised with eased arrises |
What it's used for
- Floor joists in domestic and commercial timber frame construction
- Roof rafters and ridge boards where C24 grade is specified by an engineer or building control
- Studwork in load-bearing timber frame walls
- General structural carcassing where span and load capacity require a higher grade than C16
Fitting and handling
Allow the timber to acclimatise on site for at least 24 to 48 hours before fixing, keeping it stacked flat on bearers off the ground and under cover to prevent moisture uptake. Use galvanised or stainless steel fixings throughout to avoid corrosion staining, and where joist hangers or structural connectors are specified, ensure they are rated for C24 timber. Store any unused lengths flat and supported at regular intervals to prevent bowing.
FAQ
What is the difference between C16 and C24 structural timber?
C24 is a higher stress grade than C16, meaning each piece has been tested and confirmed to carry greater loads over longer spans. It is specified where structural calculations or building control require increased strength, for example in floor joists at wider centres or in roof rafters with longer rafter runs.
What does regularised mean on sawn timber?
Regularised timber has been passed through a planer to bring all pieces to a consistent depth, which makes it easier to achieve level floors and plumb walls without packing. The arrises (corners) are also eased to reduce the risk of splits and splinters during handling. The face and edge remain sawn in appearance rather than fully smooth.
Is this timber suitable for use in a structural floor without further treatment?
For most above-ground internal floor joist applications in a ventilated, dry environment this section can be used without preservative treatment. If the timber will be close to or in contact with masonry, near an external wall, or in a poorly ventilated subfloor void, a preservative-treated section should be considered. Always confirm requirements with your structural engineer or building control officer.
Browse the full range of C24 graded timber at Nottage Timber Merchants. We supply trade and retail customers across South Wales, with next-day delivery available to the Bridgend area and surrounding regions.
