Due Diligence on a 100-Year-Old House

Sills, joists and the crawlspace. The sill is the horizontal timber the whole frame sits on. On an eastern North Carolina house with a low crawlspace and a century of moisture, it is the single most common expensive failure. Look for it specifically: soft wood at the perimeter, sloping floors that follow an exterior wall, doors that will not latch on one side of the house. Sill and band replacement is real money and it is not optional.

Foundation and piers. Brick pier foundations move. Some movement is old and settled; some is active. A structural engineer — not a foundation-repair company offering a free estimate — is the right person to tell you which. Pay for the engineer. The report is also the document that makes a price renegotiation credible.

Roof, and what is under it. Age of covering matters less than whether the decking and framing are sound and whether there has been long-term leakage. Attic inspection, from inside, with a flashlight. On a district property, note that changing roofing material is exterior work — see Chapter 2 before you assume you can swap to architectural shingle.

Water management. Grading, gutters, downspout discharge, crawlspace vapor barrier and drainage. More old-house structural damage traces back to water that was never directed away from the building than to any other single cause. It is also among the cheapest things to fix, which is why it is worth finding.

Termites and wood-destroying organisms. A WDO report is standard and cheap. On a pre-1940 house in this climate, treat previous damage as expected and the question as "how much, and is it active."

Electrical. Knob-and-tube wiring, cloth-insulated conductors, fuse panels, ungrounded two-prong outlets and undersized services are all normal findings on this stock. The practical issues are safety and insurability — some carriers will not write a policy on active knob-and-tube, and some will surcharge it. Ask your insurance agent during due diligence, not after. Have a licensed electrician scope a full rewire even if you do not intend to do it immediately, so you know the number.

Plumbing supply and drain, separately. Two different problems. Supply side: galvanized steel pipe corrodes internally and shows up as poor pressure long before it leaks. Drain side: cast-iron waste lines rust from the inside out and fail without warning. A sewer scope — a camera run from the house to the main — costs a small fraction of what a collapsed lateral costs and is one of the highest-value inspections available on an old house. Get it.

Heating and cooling. Many houses in this stock have had systems added rather than designed — window units, later a heat pump, ductwork threaded through closets and crawlspaces. Ask what the actual conditioned envelope is, where the ducts run, and whether the crawlspace ductwork is insulated and sealed. Undersized or leaking duct in an unconditioned crawlspace is why an old house can have a new system and still cost a fortune to heat.

Lead-based paint. For any dwelling built before 1978, federal law requires the seller to disclose known lead-based paint and hazards and to give the buyer the EPA pamphlet, and gives the buyer a 10-day opportunity to conduct a lead inspection or risk assessment unless waived in writing.¹ Contractors doing renovation, repair or painting that disturbs lead paint in pre-1978 housing generally must be EPA RRP-certified and follow lead-safe work practices.² This is not a formality on a house with a hundred years of paint layers; it changes who can legally do your work and what it costs.

Asbestos. Common in pre-1980 buildings in floor tile and mastic, pipe and duct insulation, some siding and some roofing. Undisturbed and intact, it is generally left alone. The problem arises during demolition — which is exactly what a restoration is. Budget for testing before you plan a gut.

Plaster versus drywall. Original plaster over wood lath is a feature worth keeping and a skill that is genuinely scarce. Ask early whether you can get a plasterer at all. If the answer is no, that changes the scope from "repair" to "replace," which changes the budget and, on a contributing structure, potentially the tax-credit treatment.

Survey. Old parcels in old towns have old descriptions. Encroaching outbuildings, fences that are not on the line, driveways crossing a neighbor's corner and gaps between deed calls are all normal. A current survey is not required to close and is frequently worth paying for anyway.

Flood zone, for the parcel. Get the determination on the specific parcel, in writing, and get an insurance quote in writing. See the River & Floodplain Brief, Chapter 2.

Contributing status and district boundaries. Whether the building is a contributing structure inside the National Register district determines tax-credit eligibility; whether the parcel is inside the local district determines whether you need a Certificate of Appropriateness. They are different maps. Confirm both. Chapter 2 covers how.

Well and septic, in the rural townships. Outside the Tarboro, Princeville and Rocky Mount systems, a lot of Edgecombe County is on private well and on-site septic. Ask for the septic permit and system layout from Edgecombe County Environmental Health, get the tank pumped and inspected as a condition, and test the well water. A failed drainfield on heavy soil is a five-figure problem.