Specifying carcassing timber by price alone is how you end up back on site. A practical look at grades, treatment levels and lead times for Greater Manchester joiners and builders.
Carcassing timber is the line item most often changed on site — usually because the grade or treatment specified doesn't match what the job needs.
C16 vs C24 in plain terms
Both are structural graded softwood. C24 is stronger and stiffer, which usually means it can span further or carry more at the same section size. C16 is fine for a great deal of domestic work where spans are modest and the design allows it.
The rule of thumb: don't downgrade from a structural engineer's spec to save money on a pack of timber. The saving is small and the liability is not.
Treatment levels
For anything in ground contact or persistently damp conditions you need the higher use class treatment. Standard UC2 treated carcassing is intended for internal, dry-risk applications. Roofing batten is a separate specification again — it must be graded to BS 5534 and marked as such.
Moisture content and movement
Kiln-dried, regularised timber is more consistent in section and moves less after installation. If you're studding out for a plaster finish, consistency saves you more time than the price difference costs.
Lead times
Standard sections in common lengths should be off-the-shelf. Long lengths, larger sections and engineered joists are typically special order. Ask for a realistic date, not an optimistic one, and book your labour around the confirmed date.
We hold C16 and C24 treated carcassing, sheet materials, batten and studwork at our Manchester depot with cutting available at the counter. Call 07342 277485 to check stock.