Before 1920: Victorian-Era and Early Brick Construction
St. Louis was one of the largest cities in the country in the late 1800s, and the housing stock from that era reflects it. Neighborhoods like Lafayette Square, Soulard, and the Central West End have significant concentrations of Victorian-era homes, many still in use and structurally sound after 100+ years.
But the systems are a different story. Homes built before 1920 present the most complex inspection considerations in the St. Louis market.
Electrical: Original Knob-and-Tube
Homes from this era were wired with knob-and-tube systems, which use separate hot and neutral wires run through ceramic insulators and knobs. Knob-and-tube worked fine for the electrical loads of its era, but it wasn't designed for modern demand. More importantly, it has no ground, which affects how modern appliances operate and what grounded outlets you can legally install.
Some Victorian homes have been fully rewired. Others have partial updates — a new panel with circuits added while original wiring remains active in parts of the house. Partial updates require careful evaluation because mixed systems can create unexpected interactions. Verify what's active during the inspection.
Most insurance carriers will either decline coverage or charge significant surcharges for active knob-and-tube wiring. Get clarity on the electrical status before you're in contract.
Plumbing: Lead Pipes and Clay Tile
Supply lines in pre-1920 homes are frequently lead. Lead supply lines are found both inside the house and as the service line from the street main. The EPA recommends testing tap water for lead content if the service line or interior supply material is unknown.
Drain lines are typically cast iron for in-house stacks and clay tile for the sewer lateral. Cast iron is durable but corrodes over time. Clay tile laterals are the subject of St. Louis's mandatory sewer lateral inspection program — expect this to be an issue on any pre-1920 property.
Foundation: Stone and Brick
Foundations from this era are typically stone rubble or brick, not poured concrete. Stone and brick foundations are not waterproof — they rely on drainage management to stay dry. Efflorescence (white mineral deposits), staining, and minor seepage are common. Significant water intrusion requires attention to exterior grading and drainage before interior waterproofing.
Structural concerns in stone foundations are usually visible: major cracking, bowing, or mortar joint failure. Have significant findings evaluated by a structural engineer if your inspector recommends it.
1920s-1940s: The Brick Bungalow Era
This is the defining era of St. Louis residential construction. The brick bungalow — one to one-and-a-half stories, full basement, detached garage, front porch — is the dominant housing type across dozens of St. Louis City neighborhoods and inner-ring suburbs like Webster Groves, Maplewood, and Clayton.
Structurally, these homes have held up extraordinarily well. Solid brick construction, quality lumber, and straightforward floor plans have made them durable. But the systems are aging.
Electrical and Plumbing
Homes from the 1920s-1940s were typically wired with knob-and-tube, transitioning to early cloth-insulated wiring by the late 1930s and 1940s. Many have been updated, but the quality of updates varies significantly. Look for a service upgrade to at least 100-amp service and verify grounded circuits throughout.
Plumbing supply lines in this era are primarily galvanized steel. Galvanized corrodes from the inside over decades, gradually reducing flow and eventually failing. Homes approaching the 100-year mark with original galvanized supply lines are candidates for replumbing. Galvanized under pressure can also show low water pressure in showers and fixtures even when municipal pressure is adequate.
The Sewer Lateral Question
Clay tile sewer laterals are standard in this era, and St. Louis City requires inspection certificates for all property sales regardless of home age. Expect the lateral inspection to show some level of condition issue on properties from this era — root intrusion, joint offsets, and minor cracking are common. Significant collapse or complete blockage is less common but not unusual on 80-100-year-old laterals in neighborhoods with mature tree canopies.
1945-1965: Post-War Ranch and Split-Level
Post-WWII construction in St. Louis expanded rapidly into the western suburbs — Kirkwood, Creve Coeur, Florissant, Ferguson. Ranch homes and split-levels on larger lots with attached garages were the new normal.
These homes generally have more modern systems than the brick bungalow era, but they're now 60-80 years old and showing age in predictable ways.
Electrical systems from this period used early Romex wiring. By the mid-1960s, aluminum wiring was introduced as a copper substitute during a copper shortage — homes built from approximately 1965 to 1973 may have aluminum branch circuit wiring, which requires special connectors and devices rated for aluminum. Aluminum wiring was phased out after fire safety concerns were documented. Check whether aluminum wiring is present and whether it's been properly managed with approved co-wired connections or pigtails.
Plumbing from this era is typically copper supply lines — more durable than galvanized but now old enough to show signs of wear at soldered joints and valve bodies. Cast iron drain lines and original clay tile laterals are still standard for homes in St. Louis City boundaries.
1965-1990: Concerns from This Era
Two issues from this construction era are worth specific attention in St. Louis and nationally:
Polybutylene supply lines: Used extensively from the late 1970s through the 1990s, polybutylene (identified by gray, blue, or black plastic pipe) was recalled and phased out after high failure rates. Homes in St. Louis suburbs built or replumbed during this period may have polybutylene. Insurers may require replacement, and failure risk increases with age. See our full guide on polybutylene pipe concerns.
Federal Pacific and Zinsco electrical panels: These brands, common in homes from the 1960s through 1980s, have documented failure issues with their breakers. A Federal Pacific Stab-Lok or Zinsco panel should be evaluated by a licensed electrician and often replaced. See our guide on Federal Pacific panels for more detail.
Other typical concerns in this era: HVAC systems approaching end of service life, original water heaters, and attic insulation that may contain asbestos-containing materials in some formulations. Asbestos insulation concerns are worth a specialist evaluation if the material is disturbed or damaged.
2000 to Present: Newer Construction
Post-2000 construction in the St. Louis metro is generally in good shape from a systems standpoint. Modern wiring, copper or PEX supply lines, and updated HVAC standards mean that the catastrophic systems issues of older eras are largely absent.
That doesn't mean new construction inspection is a formality. Common issues in newer St. Louis homes include improperly flashed roof penetrations, HVAC installation shortcuts, and grading problems that direct water toward foundations rather than away. The sewer lateral requirement in St. Louis City still applies — even newly constructed homes in the city must have lateral inspections, and connections to the older municipal system sometimes introduce issues regardless of the home's age.
Clay soil movement affects every era of construction in the St. Louis area. Newer homes built on expansive clay without adequate preparation can show foundation movement within the first decade. If a newer home shows sticking doors, diagonal cracks at window corners, or visible foundation cracking, those findings deserve attention even in homes that seem recently built.