Home Insurance Red Flags by Building Era

Quick answer

Insurers ask about specific era materials by name: knob-and-tube wiring, aluminum branch wiring, federal pacific (fpe) stab-lok panel, zinsco / sylvania-zinsco panel and more. The questions appear on applications and 4-point inspections, and the answer changes premiums, exclusions or insurability itself. This page lists every documented item, its years, and what carriers do about it — informational only, not insurance advice.

Items carriers commonly ask about by name

ItemYearsWhat carriers typically do
Knob-and-Tube Wiringpre-1950Many carriers ask directly about knob-and-tube on applications and 4-point inspections; some require replacement or an electrician's letter before binding coverage.
Aluminum Branch Wiring1965–1973A standard question on many homeowner applications and 4-point forms; carriers often accept documented COPALUM or AlumiConn remediation in lieu of a rewire.
Federal Pacific (FPE) Stab-Lok Panel1950–1985Frequently a named item on insurer questionnaires and 4-point inspections; some carriers decline or require replacement before binding coverage.
Zinsco / Sylvania-Zinsco Panel1955–1980Named on some carrier red-flag lists alongside FPE; expect questions on a 4-point inspection in Florida and other 4-point states.
Polybutylene (Poly-B) Pipes1978–1995A named question on many applications; some carriers decline, exclude water damage or surcharge until poly-B is replaced.

Items that surface on inspections, not applications

  • Ungrounded Two-Prong Outlets (pre-1962) — Rarely a hard stop on its own, but 4-point inspections note ungrounded outlets and some carriers ask about them alongside panel age.
  • Asbestos-Containing Materials (pre-1980) — Standard homeowner policies typically exclude asbestos remediation, so it is a renovation budget item rather than a claim.
  • Vermiculite Attic Insulation (1920–1990) — Generally excluded from homeowner policies; treat it as a disclose-and-budget item rather than an insurable loss.
  • Galvanized Steel Supply Pipes (pre-1960) — 4-point inspections record supply pipe material; some carriers surcharge or ask for repipe plans on mostly-galvanized systems.
  • Kitec Plumbing & Fittings (1995–2007) — Less often named than poly-B, but adjusters know it; a history of fitting leaks can affect water-damage coverage terms.
  • Orangeburg Sewer Pipe (1945–1972) — Standard policies usually exclude wear-based lateral failure; separate service-line endorsements exist and commonly ask about pipe material and age.
  • Cast Iron Drains at End of Life (pre-1975) — In Florida and similar markets, carriers increasingly ask about cast iron drains in pre-1975 homes; some exclude resulting water damage until replacement.
  • Corrosive Imported Drywall (2001–2009) — Most homeowner policies exclude it as a construction defect; historical cases ran through litigation and settlements, so disclosure is critical in affected states.
  • Hardboard / LP Inner-Seal Siding (1985–1996) — Carriers may photo-document deteriorated siding at renewal; rot is excluded as maintenance, so unrepaired swelling can trigger non-renewal notices in some markets.
  • Barrier EIFS (Synthetic Stucco) (1980–1999) — Some carriers in Southeastern states ask about EIFS cladding or decline barrier-EIFS homes; a documented passing probe inspection helps at binding.
  • Unbonded Yellow CSST Gas Line (1990–2012) — Some carriers in lightning-prone states ask about CSST bonding; loss history has made it a known underwriting topic.
  • Outdated Smoke/CO Alarm Coverage (pre-2010) — Carriers rarely ask beyond whether working smoke detectors exist, but discounts for monitored or interconnected systems are common.

What actually moves the answer

Three things consistently help: permits (a permitted panel replacement or repipe closes the question), professional documentation (a COPALUM/AlumiConn remediation invoice, an electrician's K&T letter), and photos of data plates proving component ages. Verbal assurances and unpermitted work generally do not. If one carrier declines, others may not — era items are underwriting appetite, not law.

Frequently asked questions

Will insurers refuse to cover a house with polybutylene pipes?

Some decline outright, others exclude water damage or add a surcharge, and a few bind normally after documentation. Practice varies by carrier and state. A completed repipe with permits typically restores standard-market options — budget-wise, repipes are commonly cited in the $4,000–$12,000 range.

Do I have to disclose era items I know about?

Application questions must be answered truthfully — a wrong answer risks rescission after a claim. If a form asks about knob-and-tube, aluminum wiring or panel brand and you do not know, say so and let the 4-point inspection answer it rather than guessing.

Which home eras get the most insurer scrutiny?

Pre-1950 (knob-and-tube, galvanized), 1965–1973 (aluminum branch wiring), 1950–1985 (FPE and Zinsco panels) and 1978–1995 (polybutylene) draw named questions. Homes after the mid-1990s mostly face component-age questions — roof and water heater — rather than material-era ones.