Iowa Code § 572.3
No person shall be entitled to a mechanic’s lien who, at the time of making a contract for furnishing material or performing labor, or during the progress of the work, shall take any collateral security on such contract.
[C51, §1009; R60, §1845; C73, §2129; C97, §3088; C24, 27, 31, 35, 39, §10272; C46, 50, 54, 58, 62, 66, 71, 73, 75, 77, 79, 81, §572.3]