Written by Acorn Sales Company, manufacturing stamps and seals since 1964 · Reviewed by Holly R, VP of Sales and Marketing at Acorn Sales, against the Illinois Department of Financial and Professional Regulation, advised by the Interior Design Board and 68 Ill. Adm. Code 1255.45 on 21 September 2026 · Updated 21 September 2026
Your seal carries three items and your expiration date goes beside it, not in it. 68 Illinois Administrative Code § 1255.45 requires “a reproducible seal, or facsimile, the print of which shall contain the name of the registered interior designer, the registration number, and words ‘Registered Interior Designer, State of Illinois’.” Subsection (a) then puts the rest outside the print: “The individual registrant’s written signature and date of signing, along with the date of registration expiration, shall be placed adjacent to the seal.”
That expiry line is the thing to design around. Every registration under the Registered Interior Designers Act expires on August 31 of odd numbered years, so the line is identical for every registrant in the state and turns over for all of them at once. A die with the date engraved into it goes stale on that fixed schedule. The suggested facsimile at subsection (c) shows the right answer: three ruled lines beneath the impression, for the signature, the date signed and the words Registration Expires.
One seal covers a set, and the trigger is narrower than you might expect. The seal goes on the first sheet of any bound set or loose sheets of technical submissions used as contract documents between the parties, or prepared for the review and approval of any governmental or public authority “having jurisdiction to issue a permit.” That is the opposite of the Texas sheet by sheet rule, and the permit clause is worth reading before assuming a filing is covered.
Illinois interior designer seal requirements at a glance
| Requirement | Illinois rule | Source |
|---|---|---|
| Seal required | Yes | 68 Ill. Adm. Code 1255.45 |
| Required elements | Your name as registered, Your registration number and The words Registered Interior Designer, State of Illinois | 68 Ill. Adm. Code 1255.45 |
| Size and shape | Not addressed. Section 1255.45 prescribes content and calls its figure a suggested facsimile, with no dimension. Checked the whole of Part 1255, whose sections run from 1255.10 to 1255.90. Only the Illinois geologist. | 68 Ill. Adm. Code 1255.45 (silent) |
| Device allowed | A reproducible seal or facsimile. | 68 Ill. Adm. Code 1255.45(b), (c) |
| Signature and date | Seal, written signature, date of signing and date of registration expiration, all on the first sheet and all adjacent to the impression. | 68 Ill. Adm. Code 1255.45, 1255.45(a), (b) |
| What must be sealed | Technical submissions used as contract documents between the parties to a contract, or prepared for the review and approval of any governmental or public authority having jurisdiction to issue a permit, prepared by the registered interior designer or under that person’s responsible control. | 68 Ill. Adm. Code 1255.45 |
| Electronic seal | Not addressed as a sealing technology, and permissive on signatures. | 68 Ill. Adm. Code 1255.45(b) |
| Renewal and lapse | Every registration issued under the Registered Interior Designers Act expires on August 31 of odd numbered years, renewable during the month preceding. | 68 Ill. Adm. Code 1255.60(a), 1255.45(a) |
| Firm requirements | Not addressed in the seal section. | 68 Ill. Adm. Code 1255.45 |
| Regulator | The Illinois Department of Financial and Professional Regulation, advised by the Interior Design Board | Registered Interior Designers Act, 225 ILCS 310 |
Is a seal required in Illinois?
Illinois registers interior designers and gives them a seal. 68 Illinois Administrative Code 1255.45 provides that “Every registered interior designer shall have a reproducible seal, or facsimile, the print of which shall contain the name of the registered interior designer, the registration number, and words ‘Registered Interior Designer, State of Illinois’,” and then fixes the trigger: the registered interior designer “shall affix the signature, current date, date of registration expiration and seal to the first sheet of any bound set or loose sheets of technical submissions utilized as contract documents between the parties to the contract or contracts or prepared for the review and approval of any governmental or public authority having jurisdiction to issue a permit by that registered interior designer or under that registered interior designer’s responsible control.” The section was amended effective August 2, 2024 at 48 Ill. Reg. 12276.
What must appear on the seal
- Your name as registered
- Your registration number
- The words Registered Interior Designer, State of Illinois
Three elements inside the print and three more beside it. The print carries the name, the registration number and the words Registered Interior Designer, State of Illinois. Subsection (a) puts the rest outside: “The individual registrant’s written signature and date of signing, along with the date of registration expiration, shall be placed adjacent to the seal.” Subsection (c) calls the printed figure “a suggested facsimile of the design and lettering of the seal” and shows the layout with three lines beneath the impression, a signature line, a date signed line and a line reading Registration Expires. So the artwork is guidance and the lettering is mandatory. Nothing authorizes a firm name, an NCIDQ reference or a specialty line inside the print.
Size and shape
Not addressed. Section 1255.45 prescribes content and calls its figure a suggested facsimile, with no dimension. Checked the whole of Part 1255, whose sections run from 1255.10 to 1255.90. Only the Illinois geologist seal has a prescribed diameter, at one and three quarter inches under 68 Ill. Adm. Code 1252.APPENDIX A.
Embosser, rubber stamp or digital
A reproducible seal or facsimile. The word reproducible is the test: the print must survive copying, so a dry embosser alone is not a safe device. Subsection (b) gives the registrant a free choice of signature form, which may be an original signature in the registrant’s handwriting, a scanned copy of the document bearing an original signature, or a signature generated by a computer. The safe buy is an inked rubber or self inking stamp with three ruled lines under the impression for the signature, the date signed and the registration expiry.
Signing and dating
Seal, written signature, date of signing and date of registration expiration, all on the first sheet and all adjacent to the impression. Two dates are in play and buyers conflate them: the current date is the day the registrant signs, and the date of registration expiration is the statewide renewal date. Illinois does not require the signature to cross the seal, and it expressly allows a computer generated signature at the registrant’s discretion, which is the opposite of Texas geoscience, where a handwriting font signature is prohibited.
Illinois gives interior designers a full seal, an expiry line and a permit trigger
Illinois is one of the minority of states where a registered interior designer carries a real seal rather than a signature. Section 1255.45 builds it the same way Illinois builds its architect and engineer devices: a reproducible print with the name, the registration number and the words Registered Interior Designer, State of Illinois, and then a block beside it carrying the written signature, the date of signing and the date of registration expiration.
Which documents must be sealed
Technical submissions used as contract documents between the parties to a contract, or prepared for the review and approval of any governmental or public authority having jurisdiction to issue a permit, prepared by the registered interior designer or under that person’s responsible control. The seal goes on the first sheet of any bound set or loose sheets rather than on every sheet, which is the Illinois pattern across the design professions and the opposite of the Texas sheet by sheet rule at 22 Texas Administrative Code section 5.113(a)(3).
Electronic and digital seals
Not addressed as a sealing technology, and permissive on signatures. Section 1255.45(b) allows a computer generated signature at the registrant’s sole discretion and a scanned copy of a document bearing an original signature, and Part 1255 names no certificate authority, hash standard or verification test. Note that the Illinois architect statute and the Illinois landscape architect rule both say expressly that the seal and dates may be electronically affixed; section 1255.45 does not carry that sentence. Checked the whole of Part 1255.
Renewal, lapse and retirement
Every registration issued under the Registered Interior Designers Act expires on August 31 of odd numbered years, renewable during the month preceding. Because the date of registration expiration must appear adjacent to the seal, the block beside the print turns over on a fixed statewide schedule and any device that engraves that date is obsolete each cycle. The registration number does not change on renewal. Nothing in Part 1255 requires the seal to be surrendered or destroyed on lapse, inactive status or discipline.
Firm requirements
Not addressed in the seal section. Section 1255.45 contains no firm clause, unlike the Illinois architect statute at 225 ILCS 305/14 and the land surveyor rule at 68 Ill. Adm. Code 1270.58(c), which both require the corporate or assumed business name and design firm registration number on technical submissions. Checked the whole of Part 1255. The seal itself carries only the registrant’s name, number and legend, so no firm identifier belongs in the print in any event.
What to check before you order
Letter the ring exactly: Registered Interior Designer, State of Illinois. Inside, put your name as registered and your registration number, and nothing else. Beneath the impression, ask for three ruled lines matching the suggested facsimile in the rule: signature, date signed, and Registration Expires. Do not engrave the expiration date, because every Illinois interior design registration expires on August 31 of odd numbered years and an engraved date goes stale on that fixed schedule. Choose a reproducible inked stamp rather than a dry embosser. Leave out any firm name or certification reference.
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Frequently asked questions
Is a seal required for an Illinois registered interior designer?
Yes. Section 1255.45 requires every registered interior designer to have a reproducible seal and to affix the signature, current date, date of registration expiration and seal to the first sheet of any bound set or loose sheets of technical submissions used as contract documents between the parties, or prepared for the review and approval of any governmental or public authority having jurisdiction to issue a permit, prepared by the registrant or under the registrant’s responsible control. The section was amended effective August 2, 2024 at 48 Ill. Reg. 12276.
What goes inside the Illinois interior designer seal?
Three things and nothing else: your name as registered, your registration number, and the words Registered Interior Designer, State of Illinois. No firm name, no NCIDQ reference and no specialty line is authorized inside the print.
What size is an Illinois interior designer seal?
No dimension is prescribed. Section 1255.45 prescribes content and calls its printed figure “a suggested facsimile of the design and lettering of the seal,” with no size stated, and the whole of Part 1255 runs from § 1255.10 to § 1255.90 without adding one. Only the Illinois geologist seal carries a prescribed diameter, at one and three quarter inches under 68 Ill. Adm. Code 1252.APPENDIX A. Pick a size that keeps the lettering legible after copying.
Should the expiration date be engraved on the die?
No. Every Illinois interior design registration expires on August 31 of odd numbered years under § 1255.60(a), so an engraved date is obsolete on a fixed statewide schedule. Order three ruled lines beneath the impression instead, matching the suggested facsimile: a signature line, a date signed line, and a line reading Registration Expires.
What is the difference between the two Illinois dates?
They are easy to conflate. The current date is the day you sign. The date of registration expiration is the statewide renewal date. Section 1255.45(a) requires both to sit adjacent to the seal, alongside your written signature.
Rubber stamp or embosser in Illinois?
The rule’s word is reproducible, and that is the test. A print that does not survive copying does not meet it, so a dry embosser alone is not a safe device. An inked rubber or self-inking stamp with three ruled lines underneath is the practical buy.
Does my signature have to cross the Illinois seal?
No. Section 1255.45(a) places the signature adjacent to the seal rather than across it. Subsection (b) then gives you a free choice of signature form: an original signature in your handwriting, a scanned copy of the document bearing an original signature, or a signature generated by a computer. That is the opposite of the Texas geoscience rule, which prohibits a handwriting font signature.
Which Illinois documents get the seal?
Technical submissions used as contract documents between the parties to a contract, or prepared for the review and approval of any governmental or public authority having jurisdiction to issue a permit, prepared by you or under your responsible control. The seal goes on the first sheet of any bound set or loose sheets rather than on every sheet, which is the Illinois pattern across the design professions.
Can I seal Illinois interior design documents electronically?
Part 1255 does not treat electronic sealing as its own technology and names no certificate authority, hash standard or verification test. What it does allow, at § 1255.45(b), is a computer generated signature at your sole discretion and a scanned copy of a document bearing an original signature. Note that the Illinois architect statute and the Illinois landscape architect rule both say expressly that the seal and dates may be electronically affixed, and § 1255.45 does not carry that sentence.
What happens to my Illinois seal when the registration lapses?
The registration number does not change on renewal, so the die itself stays current. What turns over is the expiry line beside it, on the August 31 odd-year cycle in § 1255.60(a). Nothing in Part 1255 requires the seal to be surrendered or destroyed on lapse, inactive status or discipline.
Does my firm name or number go on an Illinois interior design submission?
Section 1255.45 contains no firm clause, unlike the Illinois architect statute at 225 ILCS 305/14 and the land surveyor rule at 68 Ill. Adm. Code 1270.58(c), which both require the corporate or assumed business name and design firm registration number on technical submissions. The seal itself carries only your name, number and legend, so no firm identifier belongs in the print in any case.
