You approved a sample. Weeks later, something slightly different arrives on site, and the client notices. Spec substitution and batch variation are among the most common - and most preventable - causes of rework on interior projects in Cambodia. Here is how to stop them.
Most project delays and disputes do not come from bad design. They come from the material that turns up not matching the material that was approved. It happens quietly: a supplier runs out of stock and swaps an alternative, or the same product arrives from a different dye lot. By the time it is noticed, it is on the wall. This guide explains why it happens, what it costs you, and the five steps that prevent it.
Why spec substitution happens
- Stock gaps - the approved product is unavailable, so the supplier substitutes a "similar" one to keep the schedule moving, often without sign-off.
- Batch and dye-lot variation - even the correct product can vary in colour or texture between production runs.
- No written specification at order - if the PO does not name the exact product code and batch, there is nothing to hold the supplier to.
- Cost-down after award - a cheaper equivalent is slipped in to protect margin.
What it actually costs
Substitution is expensive precisely because it is caught late.
| Impact | Consequence |
|---|---|
| Visible variation | Client rejects the work |
| Rework | Strip out, reorder, reinstall |
| Delay | Reorder lead time pushes the opening |
| Reputation | The designer or contractor wears the blame |
The five steps that prevent it
1. Lock the specification in writing
Approve against an exact product code, colour and finish - not "a grey carpet, around this." Vagueness is what substitution hides behind.
2. Reserve the exact batch
Approving a sample is not the same as securing the stock. Require the supplier to reserve the approved batch and print the batch number on the PO.
3. Put a written delivery date on the PO
A delivery date you can hold the supplier to - ideally backed by a credit if missed - removes the incentive to substitute when stock runs short.
4. Require a Spec Lock Certificate
Insist on a signed document confirming the delivered batch matches the approved specification, line by line. It gives you and your client an auditable record.
5. Check on delivery, before install
Compare the delivered batch to the retained sample before anything goes on the wall or floor. Catching a mismatch in the box costs nothing; catching it on the wall costs the job.
How we lock the specification
Material Supply Pro builds these five steps into every order as standard: we reserve the approved batch, print the batch number on the PO, issue a Spec Lock Certificate confirming the delivered batch matches your specification, and put a written delivery date on every purchase order - backed by a credit if we miss it. It is the core of how we work. Read about our hotel fit-out approach, see it on real projects, or join the Trade Program to specify us with confidence and earn commission while you do.
