Building material substitution should start with a comparison of the proposed product against the specified product, its intended function and its connections to the surrounding work. A similar appearance or shared material name is not enough to establish equivalence. For a company procuring from China, the useful question is whether the changed assembly can still satisfy the project brief and the requirements accepted by the responsible project team.
This guide sets out fields a buying company can use to describe that comparison. It is procurement advice, not a universal statutory approval process or a claim that FBM Sourcing operates a formal substitution approval scheme. The local designer, contractor and approval authority determine the decisions relevant to their project. Keep technical acceptance separate from the commercial decision to order a changed product.
Define the building material substitution before comparing it
Identify the original item code, specification reference and drawing revision first. Then identify exactly what would change: the complete product, one component, a finish, a fixing, an accessory or an installation detail. A proposal described only as an alternative window or equivalent board leaves too much unresolved. Record both the original description and the proposed description without quietly rewriting the original requirement.
State the reason for considering the alternative in plain language. It may concern the required appearance, a construction detail or the availability of a particular specification. Do not claim a saving or a delivery improvement before those matters are supported by an actual quotation and project programme. A reason to explore an alternative is not evidence that the alternative has already been accepted.
Keep the comparison tied to the current drawings
A product comparison should identify the room, opening or elevation where the changed item will be used. The same product may meet one location’s brief while conflicting with another location’s dimensions or intended exposure. Mark the affected item codes on the current drawings and list the corresponding quantities. Where the proposal is limited to one area, do not let its acceptance spread silently across every similar item in the project.
Our guide to sending BOQs and drawings explains the information needed to begin a procurement discussion. For an alternative product, include the original drawing and the marked proposal together. A revised image without the original reference forces everyone reviewing it to reconstruct what changed, which can conceal an important difference in dimensions, materials or scope.
Compare function before finish
Begin with what the product must do in the installed building. A wall finish may need a particular cleaning approach, a door may need a defined opening function, and a cabinet may need to accommodate service access. Write the intended use beside the proposed material description. The visible colour can be considered afterwards, once the functional question is clear.
Separate required performance from a marketing description. Terms such as premium, durable, commercial grade and high performance do not identify a test, an assembly or a project acceptance criterion. Where a performance requirement exists, retain its actual wording and identify the evidence proposed to address it. Where the brief is still undecided, record it as unresolved rather than inserting an assumed default into the comparison.
Describe the complete construction
For a proposed cabinet board, distinguish the substrate, surface, edge treatment and hardware. For a door, distinguish the leaf, frame, seals, hinges, lock and glazing where applicable. For a window, distinguish the frame system, opening arrangement, glazing construction and installation detail. These descriptions allow the team to see whether the alternative changes more than its visible face.
If a component is being replaced inside a larger assembly, describe the unchanged components too. This is especially useful where the performance evidence relates to an assembled product. The alternative may retain the same general product category while changing the arrangement covered by the evidence. Avoid copying the original product performance statement beside the replacement until the responsible technical reviewer has considered the connection.
Put interfaces in their own comparison column
List the adjoining work that depends on the product. For a cabinet, this could include walls, countertop supports, appliances and service openings. For a window, it could include the opening dimensions, wall construction, flashing and surrounding finishes. For a lighting product, it could include the local electrical design and the physical mounting arrangement. Treat these as coordination questions for the project team.
A dimensional change can be important even where the visible design remains similar. Ask the responsible designer to identify the tolerances and clearance needed for the actual installation. Record any revised opening, support or adjacent finish that would result. Do not label a substitution like for like merely because its overall width and height match the schedule; depth, connections and operating space may still differ.
Match documents to the proposed product
Give every supporting document a clear connection to the proposed item. Record the document title, date, product description and stated scope. Where a report covers a particular assembly, check whether the proposal describes that assembly. A report for another size, construction or material should be shown as related information rather than presented as automatic proof of the ordered product.
Do not turn the existence of a test report into a claim that the product is approved for the whole project. The responsible reviewer needs to consider the destination requirements and the proposed use. If a document cannot be matched to the proposal, mark the connection as unconfirmed. Leaving a field open is more useful than assigning an unsupported certification statement that later becomes part of the purchase description.
Sourcing this for a construction project?
FBM Sourcing works with Developers · General Contractors · Builders · Commercial Project Owners · Interior Design & Construction Companies · FF&E Solution Providers. Send us your BOQ, drawings or product list — our team will review it and get back to you.
New Zealand example: changes can affect consented work
New Zealand’s MBIE guidance on product substitution and variations provides a useful example of why the comparison must extend beyond appearance. It says applicants should explain the substituted product’s Building Code performance and its effect on other building work. The building consent authority considers the proposal and determines the relevant treatment. Those are New Zealand-specific responsibilities, not a universal approval sequence for every importing country.
The same MBIE guidance warns that substituting components within proprietary systems can affect warranties. It also explains that where a change falls outside the conditions of a product certificate, that certificate is no longer valid for the changed use. Describe the proposed assembly and the limits of the evidence accurately; a certificate title cannot resolve whether a changed component remains within its stated conditions.
Separate visual approval from technical acceptance
A finish sample can help the design team compare colour, texture, sheen and edge treatment. It does not establish all the performance of the installed product. Label the sample with its item code and proposed construction so that its visual approval is not mistaken for approval of a different substrate or assembly. Where appearance is the only matter under review, state that limitation explicitly.
A section drawing or physical sample can also expose unresolved interfaces. Ask the project team to review how the product meets the adjacent materials and whether the proposed detail remains consistent with the drawings. Record the answer in the project documents. A meeting photograph or an informal message that says looks good may not explain which part of the proposal the person intended to accept.
Use a comparison record that exposes open questions
A useful comparison record can contain the original item reference, proposed item reference, function, dimensions, construction, interfaces, supporting evidence, appearance reference and outstanding decisions. It can also identify which drawing or schedule needs revision if the proposal is accepted. These fields organise the information; they do not create a legal approval form or replace the documentation required by a particular authority.
Keep differences visible rather than giving every row the same conclusion. If the proposed hardware differs, name the difference. If the installation support is undecided, state who needs to resolve it. If a report has not been matched to the assembly, leave the evidence connection open. A comparison that ends with specific questions is more actionable than a page that repeatedly describes the entire proposal as equivalent.
Avoid hiding changes inside a revised quotation
A quotation should make the proposed item identifiable, but its commercial acceptance should not erase unresolved technical questions. Keep the product description aligned with the agreed drawings and material references. If a quotation describes a different construction, reconcile the discrepancy before the order is placed. Our guide to BOQ-based quotation scope discusses how included and excluded work should remain identifiable.
Where several alternatives are being considered, give each a distinct reference. Do not allow the final quotation to combine the finish of one option, the dimensions of another and the evidence of a third. State which complete proposal is under consideration and retain the rejected or superseded versions as project records. The buying company can then explain what it selected without rebuilding the comparison from disconnected messages.
Coordinate drawings, quantities and handed versions
A substitute product may change which versions are required. A revised door arrangement can affect handing; a cabinet change can affect end panels; a different window opening can affect hardware descriptions. Ask the project team to reconcile these versions with the schedule before quantities are confirmed. The proposal should show the repeated item and its exceptional conditions rather than assuming every location is identical.
Our discussion of CAD and shop drawings explains the role of drawings in a procurement enquiry. A drawing-based alternative should retain readable reference dimensions and identify the proposed differences. Avoid using a rendered view as the sole record of acceptance. It can show appearance, but it may leave the technical construction, dimensions and installation conditions unspecified.
Consider operation and maintenance in the decision
Ask the operator or facilities team to review the proposed cleaning instructions, replacement components and access needs. A visually similar material may require a different cleaning product or a different repair approach. Keep those questions beside the specification, especially for public spaces and repeated rooms where the maintenance team will encounter the same detail across the building.
Record the proposed warranty wording and any conditions relevant to the changed assembly. Do not assume the original product warranty transfers to an alternative material or component. The New Zealand proprietary-system warning illustrates one reason to examine the connection, but the actual warranty position must be read in the documents relevant to the proposed product. Procurement advice cannot supply a warranty that the product documents do not provide.
Keep the installation responsibility clear
Identify which details are supplied with the product and which are designed or completed locally. A furniture or joinery package may show adjacent services for coordination while excluding their supply. A window drawing may need local confirmation of its interface with the building envelope. Document those boundaries so that approval of the product does not appear to resolve work that still belongs to another party.
If the alternative requires a revised site detail, identify the revision before treating the product as ready to order. Ask the local team to confirm the relevant measurements and substrate conditions. Avoid relying on an unverified site assumption simply because the product drawing appears complete. The point of the comparison is to surface these dependencies while the proposed change can still be reviewed coherently.
Connect the accepted proposal to the purchase description
After the responsible project team has decided on the proposal, reconcile the purchase description with that decision. Update the affected product references, drawings and schedule entries together. Our BOQ preparation guide explains why a clear schedule matters across multiple categories. For a substitution, the schedule should identify the accepted construction instead of retaining an old description beside a newly selected image.
Retain the decision record and the supporting document revisions with the order information. If a later adjustment changes the accepted construction again, treat that as a new question rather than assuming the earlier acceptance covers it. This is a practical recommendation for maintaining consistent project records, not a statement that every country requires the same form, signature or submission sequence.
Get a China procurement quote for your project
FBM Sourcing manages the entire China procurement package for overseas construction projects. Send the original specification, the proposed alternative, current drawings, quantities and project location. Identify which technical decisions the local project team has resolved and which remain open. For loose furniture within the same package, see our project furniture sourcing site.
All quotations, invoices and shipping documents are issued by FBM Sourcing — you deal with us, and we carry the responsibility. For suppliers you nominate, we charge a 5% commission; for products we source for you, we quote a direct price. QC consists of one inspection by our own team at the factory once bulk production is finished, before shipment, with photo and video records. Your own project team is welcome to attend the inspection with us.
Sourcing this for a construction project?
FBM Sourcing works with Developers · General Contractors · Builders · Commercial Project Owners · Interior Design & Construction Companies · FF&E Solution Providers. Send us your BOQ, drawings or product list — our team will review it and get back to you.
Frequently asked questions
Does matching appearance establish an equivalent material?
No. Compare the intended function, complete construction, dimensions, interfaces and supporting evidence. Visual approval should identify the appearance being accepted and any technical questions that remain open.
Who decides whether an alternative can be used?
The responsible project team and the relevant local approval authority determine the requirements for the project. Procurement advice does not replace those decisions.
Can a component change affect a proprietary system?
Yes. MBIE guidance for New Zealand warns that component substitutions can affect proprietary-system warranties and may fall outside the conditions of a product certificate. Review the actual assembly and document conditions.
What belongs in a substitution comparison?
Identify the original and proposed item references, function, construction, dimensions, interfaces, evidence and outstanding decisions. Connect the proposal to the affected drawings and schedule.
What should a company send to FBM Sourcing?
Send the original specification, marked proposed alternative, current drawings, quantities and project location, together with the technical decisions already made by the project team.
