Requesting a product substitution the consultant can approve
The specified roof drain now has a sixteen-week lead time. The subcontractor finds another model available in three weeks and wants to order it today. Its brochure says 'equivalent', but nobody has compared the connection details or obtained the required decision.
Request a substitution with a side-by-side comparison against the specified product, the reason for the change and its cost and schedule effects. Follow your contract's submission and approval procedure before purchasing or installing it. A different brand or model can affect connected work even when its main function appears similar. Give the reviewer enough information to decide rather than asking them to discover the differences.
- Check whether the contract permits substitutions at this stage and who decides them. Confirm the required form, timing and documents with the project manager before promising approval to the supplier.
- State the specified product and the proposed replacement precisely. Give the reason for the request, with current lead-time or availability evidence rather than an unsupported claim that the original cannot be obtained.
- Build a comparison using each relevant requirement. Include dimensions, performance information, materials, connection details, accessories and required documentation; identify differences and missing evidence explicitly.
- Ask the affected trades to identify interfaces and changes. Show any redesign, opening, support, maintenance or installation implications that the proposed product creates.
- Present the total cost and time effect, including related work and review time. Distinguish a supplier's available-stock date from a confirmed delivered and approved installation date.
- Submit through the agreed channel and track the decision. After approval, update the order, relevant drawings and trade instructions; if refused, keep the original procurement recovery action moving.
For US federal work using the FAR drawings clause, the contractor identifies variations in submissions and approval alone does not remove compliance responsibility. That example reinforces declaring differences; your own contract determines the substitution process and authority.
Common mistakes
- Hiding a difference in a large brochure and expecting the consultant to find it.
- Calling products equivalent without comparing the actual requirements.
- Showing only the new unit price and omitting changes to connected work.
- Ordering first, then making approval urgent because the supplier will not accept a return.
Checklist
Before issuing the request
- Procedure and authority confirmed
- Reason supported by current evidence
- Requirements compared line by line
- Differences and interfaces declared
- Total cost and time effects
- Order waits for the required decision
Check your understanding
The replacement fits the opening but uses a different connection. Can you call it equivalent?
