Drywall in Missouri - Humidity, Old Homes, and Seasonal Cracking

Missouri sits in a part of the country where drywall sees real abuse from both directions. Summers bring humid air that slows compound drying and keeps moisture levels high enough to stress improperly installed wallboard. Winters drop temperatures well below freezing, and the freeze-thaw cycling that follows puts serious stress on joints, seams, and any repair that wasn't done with flexibility in mind.

St. Louis and Kansas City are both cities with substantial pre-WWII housing stock. Many homes built between 1900 and 1950 have original plaster walls where previous owners started patching with drywall sometime in the 1970s or 80s. The result is often a wall that mixes plaster, drywall, and three generations of compound work — every layer applied by someone who learned drywall in a different era with different products. Working on these walls requires a different approach than straightforward new construction or modern renovation.

Missouri also has soil movement issues, particularly in the St. Louis area where expansive clay soils cause foundation movement that translates directly into wall cracking. Cracks that come back repeatedly in the same location — especially above doors and windows — are often a symptom of ongoing foundation movement rather than a finishing problem. Understanding the difference saves a lot of time and failed repairs.

The good news for Missouri homeowners is that the climate, while demanding, isn't extreme. The humid summers are manageable with proper ventilation, and the winters, while cold, don't reach the severity of Minnesota or the Dakotas. With attention to timing and technique, most drywall projects in Missouri can be done by capable DIYers.

Local Requirements: Missouri follows International Residential Code; no statewide contractor licensing requirement, though St. Louis City and St. Louis County have local licensing requirements