Oklahoma data
Borings, drought, earthquakes, floods and soil lab values from public records.
- Does chemical soil stabilization work on Oklahoma clay?Oklahoma highway research found lime cuts swelling in ordinary clay but can cause severe heave in high-sulfate soil; two acid additives did not cut swelling.
- Does insurance pay for Oklahoma earthquake foundation damage?Oklahoma quake claims have been paid at a low rate: in 2014 about 100 were filed and eight paid, and masonry veneer and chimneys are often excluded.
- How deep does Oklahoma soil dry out during drought?Oklahoma Mesonet research puts the active zone of seasonal moisture change at about 0.5 to 4 meters (1.6 to 13 feet), depending on soil and climate.
- How deep is bedrock in Tulsa and Oklahoma City?Public borings show rock about 9 to 15 feet under upland shale in Tulsa; in Oklahoma City, Hennessey shale ran 2 to 41 feet and Garber sandstone 20 to 95.
- How deep is rock under Tulsa and Oklahoma City?In upland Tulsa, rock is often 2 to 15 feet down; near creeks and the river, 20 to 35 feet or more. South of OKC, borings hit shale at 15.5 to 25 feet.
- How did Oklahoma's foundation code change for homes in 2022?Oklahoma's 2018 IRC rule, effective September 14, 2022, added rebar to all footings, set anchor bolt spacing and barred trenching into footing support soil.
- How does the moisture index change across Oklahoma?The Thornthwaite Moisture Index weighs rainfall against evaporation. Oklahoma gets drier east to west, and drier climates generally drive soil drying deeper.
- How far should trees be planted from a house in Oklahoma City?Oklahoma City's planting guide keeps medium and large trees at least 30 feet from buildings; most roots are shallow but spread well beyond the canopy.
- What are Oklahoma's pier and anchor rules for manufactured homes?New homes follow the federal standard or maker's instructions. Used homes need block footings, piers no more than 6 feet apart, limited shims and anchor ties.
- What do lab tests show about Oklahoma clay soils?Oklahoma subsoil clays mostly test with plasticity index in the high 20s to low 40s, and some western soils carry very high sulfate that affects lime treatment.
- What must Oklahoma home inspectors report about foundations?Oklahoma inspectors must inspect the foundation, describe signs of movement and recommend correction, evaluation or monitoring, but need not find the cause.
- What were Oklahoma's worst recent drought and wet years?Oklahoma had near-statewide drought in 2011 and 2012, its wettest month on record in May 2015, and a 2022 drought that dried soils at least 32 inches deep.
- Why does Tulsa's flood history matter for Oklahoma foundations?Tulsa's floods, peaking in 1984 on Mingo Creek, led to buyouts and floodplain rules. Creek corridors hold deep, soft deposits and shallow water.