When you need one
You need a substitution request when your product is not listed and the spec does not accept it as written. Some specs name three makers and stop. Some name one maker and allow others by request. If the spec says no substitutions, a request is unlikely to succeed.
Where the rules are
Look in two places. The instructions to bidders cover requests made during bidding. Division 01 covers the procedure in detail, usually in section 01 25 00. Many projects include a form to fill in. The rules state who can send a request. Some architects accept requests only from prime bidders, so a subcontractor sends it through a general contractor.
Before the bid and after the award
- Before the bid. The documents set a deadline, counted in days before the bid date. Approved items appear in an addendum.
- After the award. Many contracts allow substitutions only for cause, such as a discontinued product. Some allow them for a short period after award.
A request made for convenience after award is often refused. Do not count on it when you price the bid.
What a request usually includes
- The spec section and paragraph, and the product named there.
- The proposed product with full data sheets.
- A line by line comparison of the two products.
- Changes needed to other work, and who pays for them.
- Effect on the schedule and the warranty.
- Samples, test reports or a list of similar installations, if the spec asks.
What approval does and does not mean
Approval lets you use the product. It does not remove the other requirements in the section. You still owe the specified performance, finish and warranty. If the product needs changes to structure or power, the contractor usually pays.
Keep the written approval. An approval by phone is hard to prove later.
Bid documents · Updated 11 Nov 2026