Illinois A C D F G H I K L M N O P R S T U V W Illinois Construction Litigation Hold 735 I.L.C.S. § 5/13- 214After improvement to real property, but after person had knowledge, four years.Online ReferenceNational Society of Professional Engineers Home Online Reference State Statute for Construction: 6 Years*The National Society of Professional Engineers Recommends an Additional: 3 YearsRecommended Document Retention 9 Years If you would like to learn the statute of limitations of any warranty your state entitles you to, refer to our Warranties map.