BESMM4 Measurement Rules: Concrete, Formwork, Blockwork and Reinforcement

Concrete, formwork, blockwork and reinforcement make up the biggest share of most Nigerian building BoQs — often more than half of the measured work. They are also where a BESMM4 bill looks most different from the materials lists people are used to. This guide explains, in plain terms, how each is measured under the NIQS BESMM4 rules: what unit is used, how items are classified, what is deducted and what is deemed to be included in the rate.

This is a practical summary for builders, clients and students, not a substitute for the BESMM4 document itself. Always refer to the current NIQS publication and the project drawings.

1. Excavation and filling (work section 1.5)

• Excavation is measured in m³, described by type (bulk excavation, foundation excavation and so on), the level it starts from (e.g. “commencing from stripped level”) and its maximum depth band — not exceeding 2.00m, 2.00–4.00m, and so on.
• Breaking up rock and excavating below ground water are measured as “extra over” the excavation, so the extra cost is visible rather than buried in the rate.
• Earthwork support and working space are no longer measured routinely — support to the faces of excavation is only measured where it is not left to the contractor's discretion.
• Disposal of excavated material off site is measured in m³.
• Filling is measured in m² (stating the thickness) where the final thickness does not exceed 500mm, and in m³ where it is thicker. Imported hardcore beds are described with their depth.
• Damp proof membranes over 500mm wide are measured in m².

2. In-situ concrete (work section 1.11)

Concrete is measured net in m³. Nothing is deducted for the reinforcement, for cast-in accessories, or for small voids of 0.05m³ or less. Each item is classified by:

Within each class the description states the thickness band — not exceeding 300mm or over 300mm — where it is (in blinding, in structures, in staircases), whether it is poured on or against earth or hardcore, and whether it is reinforced. A typical item reads:

1.11:2.1.2/2 — Reinforced in-situ concrete (1:2:4); horizontal work not exceeding 300mm thick; in structures (suspended slabs) — m³

So a ring beam and a suspended slab are both horizontal work, while a column is vertical work — each measured as its own item.

3. Formwork (also 1.11)

This is the biggest change from a materials list. Under BESMM4 formwork is measured separately from the concrete, by the surface it forms:

No deduction is made for openings of 5m² or less, and kickers (except to walls), cutting, holes, boxings and similar labours are deemed included. That is why “concrete in columns including formwork, per m³” in a simple BoQ becomes two or three separate items in a BESMM4 bill.

4. Reinforcement (also 1.11)

• Bars are measured by weight in tonnes, kept separate by type (mild steel or high yield) and by nominal size — 8mm, 10mm, 12mm, 16mm and so on.
• Each size is further described as straight, bent, curved or links; bars over 12m long are given with their length.
• Hooks, tying wire, spacers, cutting and bending are deemed included in the rate; chairs are included unless the design specifies them.
• Fabric (BRC mesh) is measured in m², stating the fabric reference (e.g. A142, A393), the weight per m² and the minimum laps. Voids of 1m² or less are not deducted, and laps are included in the rate.

Converting from the market's “lengths” to tonnes is simple: lengths × 6m × weight per metre ÷ 1,000. A 12mm bar weighs about 0.888 kg/m, so 45 lengths of 12mm is about 0.24 tonnes. For typical rod quantities in a house, see how much iron rod a house needs.

5. Blockwork (work section 1.14 Masonry)

• Walls are measured in m², on the centre line, kept separate by thickness — e.g. 225mm (9-inch) and 150mm (6-inch) hollow sandcrete blockwork — with the mortar mix and bond stated.
• Openings and built-in items smaller than 0.50m² are not deducted. Larger openings are deducted, and for lintels, sills and the like only the full block courses actually displaced are deducted.
• Deemed included: rough and fair cutting, forming chases and holes, raking out joints for a key or for flashings, bonding to other work and the extra material in laps — none of these is measured separately.
• Damp proof courses not exceeding 300mm wide are measured in metres.

In practice this means one blockwork item per wall type, with a built-up rate per m² that covers the blocks, cement, sand and laying labour — instead of four separate material and labour lines.

Putting it together: one column, two ways

For how these items are arranged into elemental bills and the Main Summary, see BESMM4 Bill of Quantities Format. To decode the item references, see BESMM4 Work Sections and Coding System Explained.

Frequently Asked Questions

Is formwork included in the concrete rate under BESMM4?

No. Formwork is measured as separate items by the surface it forms — sides of foundations, slab soffits, sides of columns and beams, and so on.

How is reinforcement measured in BESMM4?

Bars are measured in tonnes, separated by steel type and nominal diameter and described as straight, bent, curved or links. Mesh is measured in m² with the fabric reference and laps stated.

Are window and door openings deducted from blockwork?

Openings of 0.50m² or more are deducted; smaller voids are not. Walls are measured on their centre line.

What is “extra over” in excavation?

It is the additional cost of a harder operation over the basic excavation already measured — for example breaking up rock or excavating below ground water — measured on the volume affected.

Why does a BESMM4 BoQ have fewer lines for blockwork but more for concrete?

Blockwork materials and labour fold into one m² rate per wall type, while concrete is split into separate concrete, formwork and reinforcement items — reflecting how the work is actually priced and paid for on site.