Yes, you must list the panels as separate items in the Bill of Quantities if they differ in thickness or surface finish. These variations significantly impact the design, reinforcement, mould requirements, handling, and cost of each panel.
Precast items are measured by type, and any variation in dimensions, texture, or finish constitutes a distinct type under the Standard System. Grouping them under a single item would result in inaccurate pricing, complications during manufacture, and potential disputes during valuation.
Be sure to clearly describe the surface finish (e.g., smooth off-mould, acid-etched, sandblasted, or exposed aggregate), as finishes are not deemed included and must be measured separately where applicable.
You’ll need to differentiate between the two types of landings when preparing the Bill of Quantities.
If the landing is integrated into the precast stair unit, it should be measured as part of the Precast Concrete trade. If the landing is cast in-situ, it must be measured separately under the Concrete Work section of the bill.
Do not assume that landings are included just because they appear connected on the architectural drawings. Refer to the structural drawings and precast shop drawings to confirm whether each landing is precast or in-situ. The construction method affects not only the trade classification but also the way the item is described, detailed, and costed.
You must list each proprietary system as a separate item. Even if both systems are hollow-core slabs, variations in profile, structural performance, or installation methods require separation for proper pricing. The bill must reflect the exact system or at least allow for alternative options under provisional headings if the supplier has not yet been confirmed.
No, the drip grooves are deemed included as part of the coping mould and do not warrant a separate item. However, your description must clearly indicate the requirement for drip grooves, since it affects the casting process. Do not rely on drawings alone to communicate this — state it in the BoQ.
Generally, no. Proprietary keys, dowels, and interlocks, when standard to the system, are deemed included in the precast unit rate. However, where extra anchoring, tie-backs, or unusual foundation details are specified beyond the SSMBW, these may require separate items under Precast Concrete or even Earthworks if applicable. Always clarify with the designer and specify unusual fixings separately.
Standard practice assumes a basic off-mould finish unless stated otherwise. Where decorative finishes (e.g., textured, pigmented, sandblasted) are required, they materially affect the cost and must be specified in the item. Leaving them out often leads to tender disputes or costly adjustments during construction. You must therefore clearly describe the finish.
No — if the sleeves, holes, rebates, or similar features are formed during the casting process in the factory, they are considered deemed included in the precast column item and are not measured separately.
However, these features must be clearly described in the BoQ, as they affect mould fabrication, reinforcement detailing, and quality control. For example, you might describe: “Precast concrete column with 2 no. 100mm diameter cast-in sleeves for electrical services.”
If the openings are not pre-formed, and instead require cutting or drilling on-site after delivery, this becomes post-casting work and must be measured separately — typically under Alterations or Sundries, depending on the nature of the work and the trade context.
Always verify whether the feature is created in the factory during casting or after delivery on site, as this determines both measurement and pricing approach.
Temporary bracing used to stabilise precast wall panels during erection is not deemed included in the precast item and must be measured separately. However, it does not fall under Lateral Support, as it is not stabilising soil or resisting ground pressure — it's only supporting the precast units themselves during construction.
This type of bracing is typically measured under Preliminaries (as temporary works), or included as a separate item within the Precast Concrete trade, especially if the bracing is engineered or supplied by the precast subcontractor.
The BoQ should clearly state whether the bracing is temporary (removed after permanent structural elements are in place), or permanent (e.g., steel ties or props forming part of the final structure).
Be sure to describe the bracing system’s extent and purpose to avoid assumptions — for instance: “Temporary propping of precast wall panels during erection, including supply, installation, removal, and all fixings.”
No, excavation, preparation of bedding, and backfilling for the placement of precast planter boxes must be measured separately under Earthworks. The Precast Concrete item covers only the manufacture, delivery, and installation (placing) of the box itself.
This is considered Alteration work. Any cutting, drilling, or modifying of precast concrete after casting is not part of Precast Concrete. It must be measured separately under Alterations, or sometimes Sundries, depending on the extent. Be careful not to confuse post-casting work with features cast in during production.
If the culverts and headwalls are part of the general building contract and not part of a separate civil engineering works package, they are measured under Precast Concrete. However, if they form part of a roadworks or civil drainage project, they may be measured under the relevant Civil or External Works sections. Context matters here.
No — reinforcement in precast concrete is deemed included in the unit rate unless otherwise stated. This includes standard factory-installed mesh or bar reinforcement required for structural integrity. There is no separate measurement for reinforcement under the Precast Concrete trade unless a specific exception applies.
However, your BoQ description must state that reinforcement is included, and it should reference the applicable detail drawings or specifications to ensure clarity for tenderers. For example: “Precast concrete lintel, reinforced as per Engineer’s detail C3/15.”
An exception arises when the Engineer specifies post-tensioning or special reinforcement:
Post-tensioning is a method where high-strength steel cables or tendons are tensioned after the concrete has cured, providing additional strength and reducing cracking. This is common in long-span beams, slabs, or bridge decks.
Special reinforcement may include fire-resistant bars, stainless steel, corrosion-resistant mesh, or heavily congested reinforcement cages that significantly affect the production process and cost.
In such cases, these should be measured as separate items and described accordingly.
Yes, if the item is cast before final positioning, it is still classified and measured under Precast Concrete regardless of whether it is factory-made or cast on site. However, if the contractor proposes to switch to fully in-situ casting (in position), then it would shift to the Concrete trade and should be treated as a variation.
No — if the concrete is cast in its final position on site, even using a mould or formwork, it is considered in-situ concrete and must be measured under the Concrete, Formwork, and Reinforcement trade. The key distinction lies in how the element is installed:
If it is cast off-site or elsewhere on site and then lifted or placed into position, it qualifies as precast.
If it is cast directly in its final position, it is treated as in-situ work, regardless of the method or materials used.
This distinction is important for accurate trade allocation and pricing — particularly in relation to formwork, lifting, and curing procedures. Always clarify the intended method of execution during documentation and tender review to ensure that the correct measurement rules are applied.
No, unless otherwise instructed, special transport and lifting requirements beyond normal handling are not deemed included and should be measured or itemised separately under Preliminaries or as a dedicated item. Standard handling is allowed for in the precast rate, but abnormal transport permits, escorts, and mega-cranes must be separately costed.
These elements must be measured separately under Drainage (for subsoil drains) and Earthworks (for membranes and filter fabrics). They are not deemed included with the precast wall. Precast Concrete covers the units themselves, their erection, and standard connections, but associated siteworks like drainage and geotextiles are always measured in their respective trades.
Not unless otherwise specified. Lifting sockets, anchors, and similar cast-in lifting aids used purely for manufacture, transport, and erection are deemed included in the precast concrete rates. They are not measured separately unless the project specifications explicitly require special or permanent embedded anchors for later fixing of cladding or equipment, in which case they would be separately measured.
We have a series of precast wall panels that taper from 100mm to 175mm in thickness over their height. The manufacturer’s shop drawings show this variation to accommodate structural and aesthetic needs.
Should I measure the panels using the average thickness, the thickest point, or as a lump sum? Also, what about the built-in fixings?
For tapered precast wall panels, measurement should be based on net are* and the average thickness in accordance with SSMBW. The BOQ must state the variation clearly in the description (e.g., 'tapering from 100mm to 175mm thick') and use the average for rate purposes.
If built-in fixings (e.g., cast-in plates, anchors) are included, they must be measured separately unless the description expressly states they are included in the precast rate. Typically, these would fall under 'Embedded Fixings' and be listed by number, size, or type.
The Engineer has detailed precast concrete columns with an off-centre vertical void to allow for future electrical services. The void is formed using a polystyrene former in the mould and is not structurally loaded.
Do I measure the columns as solid elements or deduct for the void? And do I include the forming of the void in the precast rate?
The void should be ignored for measurement purposes unless it exceeds 0.1m² in cross-sectional area, as per SSMBW. Since this is an internal service void formed with a removable polystyrene core and not structurally loaded, it does not warrant a deduction if it is below that threshold.
However, the forming of the void (e.g., inclusion of formers, sleeves, etc.) should be stated in the description of the column. If forming the void requires special effort, it may be priced separately as an item under Specialist Precast Requirements or embedded services coordination.
The Structural Engineer has changed the specification mid-project from standard precast floor slabs to prestressed hollow-core slabs for a few areas due to span limitations. The contractor is claiming a rate adjustment, but the BoQ just says “precast slab.” Can they legitimately ask for more money?
Yes, the contractor may have grounds to claim a variation. Hollow-core slabs, particularly prestressed types, involve a different manufacturing process, reinforcement approach, and sometimes even installation logistics compared to standard solid precast slabs.
The term “precast slab” in the BoQ is too general for contractual certainty. Prestressed elements are not “deemed included” in a generic precast slab description — they carry distinct engineering, moulding, and tensioning requirements that impact cost. If the original tender was based on standard solid precast, and the specification changed after award, a variation order should be considered, subject to verification of drawings and timing of the change.
Going forward, it’s good practice to clearly describe the type of precast slab in the BoQ, including whether post-tensioning or pre-stressing is required.
Several of our precast wall panels arrived on site with minor dimensional variances — they’re within manufacturing tolerances but don’t align perfectly with the cast-in-situ columns. The contractor wants to do minor chasing and patching on site to make the panels fit. Is this a measurable item?
Where dimensional variances fall within specified manufacturing tolerances, minor adjustments to surrounding in-situ elements or non-structural patching may be treated as incidental site coordination — especially if the BoQ includes a general clause accepting tolerances in line with precast standards.
However, if the remedial work involves:
Chasing into structural members,
Cutting, grinding, or modifying the precast units themselves, or
The use of additional fixings, grout, or shims,
then this work must be measured and valued separately, typically under Alterations, Concrete Sundries, or as a Provisional Item if anticipated.
It's good practice to state acceptable tolerances in the BoQ notes and clarify which party is responsible for fitting or accommodating variances on site. Precast work is rarely flawless in fit, so contractual clarity around who adjusts to whom is key to avoiding disputes.
