This class covers timber materials and timber works in civil engineering and building projects. It includes formwork, temporary works, joinery, carpentry, and permanent timber items like doors, windows, and fittings.
1. Scope of Class O
- Applies to all works in timber, whether temporary or permanent.
- Covers both structural and non-structural applications of timber.
- Includes:
- Timber formwork (shuttering)
- Timber centering and staging
- Timber falsework and supports
- Timber joinery (doors, windows, frames)
- Timber fittings and sundries (beads, skirtings, battens)
- Timber protection, treatment, and finishes
2. Units of Measurement
- m² → for formwork, boarding, panelling, sheeting.
- m³ → for large timber members (beams, posts, planks).
- m → for linear items (battens, beads, fillets).
- No. → for doors, windows, frames, shutters, and fittings.
- kg (rare) → for timber with special hardware (if measured separately).
3. Method of Measurement (as per CESMM4 rules)
- Formwork is measured in contact area with concrete (not by timber surface area).
- All fixing, nails, bolts, staging, and supports are deemed included unless specified.
- Waste, cutting, planning, jointing included in descriptions.
- Protective treatment (preservative, fireproofing, polishing, painting, varnishing) measured separately.
- Formwork to curved or complex surfaces must be specifically itemized.
4. Itemization & Description Rules
When preparing BOQ items under Class O, descriptions must state:
- Type of timber (hardwood, softwood, plywood, teak, sal, pine).
- Application (formwork, joinery, carpentry, staging, door/window).
- Surface/finish (sawn, planed, polished, varnished, painted).
- Treatment (seasoned, treated with preservative, fire-retardant).
- Thickness/dimensions (in mm for boards, in cm/m for beams).
5. Typical Items under Class O
(a) Timber Formwork (Temporary Works)
- Formwork for beams, slabs, walls, foundations.
- Centering and shuttering for arches, domes, curved surfaces.
- Falsework and staging for supporting formwork.
- Measured in m² (area in contact with concrete).
(b) Timber in Joinery
- Doors, windows, frames, shutters.
- Cupboards, shelves, panelling.
- Staircases, handrails, balustrades.
- Measured in No. or m².
(c) Timber Carpentry
- Roof trusses, rafters, purlins, battens.
- Joists, beams, lintels, posts.
- Measured in m³.
(d) Sundry Timber Items
- Mouldings, beads, skirtings, fillets.
- Cover strips, trims, supports.
- Measured in m (linear length).
(e) Treatment & Protection
- Timber preservative treatment (anti-termite, oil-based, water-based).
- Fire-retardant coating, polishing, varnishing.
- Measured in m² (surface area).
6. Example CESMM4 Measurement Items
- Formwork (Shuttering):
- 250 m² timber formwork to sides of beams, using 25 mm thick plywood boards, including struts and supports.
- Curved Formwork:
- 50 m² timber formwork to curved soffits of arch, double-sided, including centering.
- Timber Doors:
- 10 No. teakwood panelled doors 1.0 m × 2.1 m, polished, with hinges and locks.
- Timber Frames:
- 8 No. sal wood door frames 100 × 75 mm, fixed in wall openings.
- Roof Timber:
- 3.5 m³ softwood rafters and purlins, planed and treated with preservative.
- Panelling:
- 60 m² hardwood timber panelling, polished, including skirting and moulding.
- Treatment:
- 200 m² of fire-retardant coating to timber doors and panelling.
7. Practical Site Examples of Class O Timber Works
- Buildings: Door/window joinery, staircases, timber floors, roof trusses.
- Concrete Works: Timber formwork and staging for slabs, beams, and walls.
- Bridges: Timber decking, temporary staging.
- Industrial Works: Timber packing, supports, temporary platforms.
- Marine Works: Timber fenders, piles, protection works.
✅ Summary:
Class O (Timber) in CESMM4 includes all permanent and temporary timber works such as formwork, carpentry, joinery, and sundry items. Measurement depends on whether timber is used as formwork (m²), structural (m³), joinery (No./m²), or fittings (m). Treatments and finishes are always measured separately.
