Cornerstone Contracting Co. Share: Home Improvement & MaintenanceMasonry Cornerstone Contracting Co. Visit Website RR 5 Box 552 Ava, MO 65608 (417) 861-4274 Hours: 7:00 am - 4:30 pm Monday - Friday. About About Masonry restoration, tuckpointing, caulking, waterproofing (above ground). Residential, Commercial, Industrial. Call The Office (417) 683-4594 Office Location 810 Collins Avenue Ava, MO 65608 Email Us director@avachamber.org