You were hired to swap a panel, move a sink or finish a bathroom. The house has other plans. Somewhere behind the drywall is a previous owner's weekend project, and the moment you open the wall it stops being their project and starts being your afternoon.
Most of that work can be seen coming. The people who wire a basement themselves tend to leave the same kinds of marks everywhere they worked, and a walkthrough at the estimate is the cheapest time to find them.
What gives it away before the wall comes down
None of these proves anything on its own. Two or three together usually mean the house has more of the same where you cannot see.
Electrical
- Junction boxes with no cover, or splices sitting in an attic or crawlspace with no box at all. Wires joined outside a box leave the connection exposed to damage [CPSC].
- One cable type spliced straight into another: newer sheathed cable joined to old armored cable or to knob-and-tube, out in the open.
- Wire nuts on a run with nothing supporting it, cable left loose across joists instead of fastened to the framing.
- Two wires under one breaker screw. A double-tapped breaker is among the commonest things an inspector flags in a panel an amateur has worked on.
Plumbing
- Push-fit couplers or rubber sleeves with hose clamps where a section of drain was cut out and replaced.
- Short runs of PEX spliced into old galvanized pipe, which means piecemeal updates rather than a repipe.
- Copper joined straight to galvanized steel with no dielectric union between them.
- Accordion-style flexible drains under sinks, used to get around lining the trap up properly.
- Grey supply pipe with crimp rings. If it is stamped PB2110, it is polybutylene, and the markings are easy to check before you plan to tie into it.
Framing and venting
- Notched or drilled joists where someone routed a pipe or duct the short way.
- A bathroom fan that vents into the attic rather than outside.
Read the house's history before you price it
The local building department keeps a record of what was filed. A permit history lookup by address shows whether the finished basement, the second bathroom or the panel change was ever pulled. A finished basement with no permit on record is worth treating as a basement whose wiring was never inspected.
It takes minutes, and it changes the conversation from "I found something" after the fact to "here is what I expect we might find" before anyone has signed.
Price the part you can't see
The cost is not in the bad splice. It is in what the bad splice is attached to.
A panel job on a house with DIY branch wiring can turn into a conversation about aluminum wiring, where remediation runs $2,000 – $8,000+. Tie into a run that turns out to be knob-and-tube, and you are talking about a partial to whole-home rewire at $8,000 – $30,000+. Replace one fixture on galvanized supply, and the homeowner may be looking at a whole-home repipe at $4,000 – $15,000. Those are the ranges Before Regret's own property report uses for the same conditions, and they are general ranges, not local quotes.
The point is not to quote those jobs up front. It is to tell the homeowner, in the estimate and in plain words, that you have seen signs of earlier DIY work, that you will stop and show them anything you find, and that correcting it would be priced separately. A line like that costs nothing to write and saves the worst conversation of the job.
When you open it and it's there
- Stop where you found it. Don't cover it, and don't connect to it yet.
- Photograph it before you touch it, one wide shot so it is clear where in the house it is, and one close.
- Show the homeowner the photos, not just a description. "There's a splice in there with no box" means little to someone who has never opened a junction box. A picture of it does not need explaining.
- Separate what you found from what you were hired for. Give them the fix as its own price, so they can say yes to it on its own.
- Put their decision in writing, a short change order or a one-line note either way, so there is no question later about what was agreed.
How to tell a homeowner without losing the job
It is easy for "your house has a problem" to land as "you made a bad purchase." It helps to take the blame out of it. The work was done before they owned the house, or years before anyone noticed, and finding it now is the good outcome, because it was found by someone who knows what they are looking at.
Keep it to what you can see, show the photo, give them choices with prices, and let them decide.
If you're the homeowner
The contractor who stops work to show you something is not padding the bill. They are telling you what the house was hiding. If a home inspection report ever used the words "amateur workmanship", this is often what it was pointing at.