I am an Architect in Texas. I have a client who is holding back half of my fee on a completed set of plans. What are the deadline requirements for sending him lien notice, perhaps with a demand letter. I was under the impression that since I am working under a signed contract, directly with this property owner, that there is not a deadline.
An architect does indeed have mechanic's lien rights as long as the architect had a written contract with the owner or the owner's agent.
Assuming that you contracted with the owner or the owner's agent, your deadline for filing an affidavit claiming a mechanic's lien would be the 15th day of the fourth month (for commercial projects) or the 15th day of the third month (for residential projects) after the day on which the indebtness accrued. The term "indebtness accrues" is defined in Section 53.053 of the Texas Property Code, which you can review at the following link:
https://statutes.capitol.texas.gov/Docs/PR/htm/PR.53.htm
You really should retain a construction attorney to review and evaluate your legal position based on the contract and pertinent documents. The right to be entitled to file a mechanic's lien is set out in Texas Property Code Chapter 53, and you really need to make sure that if you file a lien, you have properly and appropriately done so.
Filing an invalid lien could subject you to liability under the Texas Fraudulent Lien Act, and you could be liable for statutory damages of $10,000, or actual damages, whichever is greater, plus attorney's fees. Facing such a claim would add insult to injury.
Good luck.