The floor comes up and the job changes category
It starts as an ordinary day. Flooring comes out, a patch of slab reads damp when everything around it is dry, and somebody puts a camera down the nearest cleanout. It comes back with a run of the original drain line that has lost its bottom somewhere under the concrete.
Nothing about the finish schedule has changed. Cabinets are ordered, tile is staged in the garage, the crew arrives tomorrow. The property has acquired work nobody priced, in a location nobody planned to reach, under a floor that was going to stay where it was.
This is the moment most jobs handle badly, and they handle it badly by treating it as a plumbing problem. It is a contract problem first. The plumbing is the straightforward part.
A concealed condition is a contract category before it is a repair
Owners tend to sort changes into two piles: things they asked for, and things that went wrong. The contract sorts them differently, and the difference decides who carries it.
An owner-directed change is a decision: a different tile, a moved wall, a wider opening. A concealed condition is something materially different from what could reasonably be observed when the work was priced, and that neither side could have found without destroying something to look. Under a slab and inside a wall cavity are the classic locations, because the only way to inspect them is to open them, and opening them is the work itself.
Most construction agreements carry a clause for this, and it does two things at once. It gives both parties a route to adjust the contract sum and the contract time, and it puts a notice requirement on that route — written notice inside a defined window after the condition is discovered, not whenever it becomes convenient to raise it. Miss that window and the mechanism the clause created stops being available, which is a poor trade for something a photograph and a dated email would have preserved.
So the first thing that should happen when the camera comes back is not a price. It is notice, dated, with the condition documented where it sits.
Nobody can price it until somebody knows how far it goes
A failure at one joint and a failure along an entire run produce the same photograph and completely different jobs. Extent drives everything downstream, and establishing it is a small scope of its own: camera the system rather than the one line, locate and mark from above, and work out whether what failed is a defect at a point or the condition of everything of that vintage under that slab.
Owners under time pressure want a number before that investigation happens, and contractors under the same pressure sometimes hand one over. That is how a single change order becomes three, each arriving after the trench has already been extended, each re-opening a schedule conversation that was closed the week before.
A property built before the mid-1970s, when plastic drain, waste and vent piping displaced cast iron as the South Florida standard, is carrying original material by default, and one failure in that system is information about the rest of it. That does not mean everything comes out. It means the scope gets decided against the whole system rather than against the hole in the floor.
What happens to a fixed-price contract when demolition uncovers a failed drain line under the slab?
A concealed condition is not a change of mind, and contracts treat the two differently. Work that differs materially from what was reasonably observable at bid time re-opens price and time through the change order the agreement already provides for. What it does not do is re-open them automatically. Notice, documentation and an approved change order come first.
The clause is a route, not an outcome. It entitles a party to ask; it does not decide the answer, and it does not survive being ignored while the crew keeps working. A trench that is dug, repaired and backfilled before anyone writes anything down has destroyed the evidence for the claim it was going to support.
The distinction between concealed and merely unexpected is where these get argued. Something visible at the walkthrough that nobody priced is not concealed — it was observable and the estimate missed it. Something under a slab that could only be found by breaking the slab is a different thing entirely, and the test is what could reasonably be seen, not what happened to be noticed.
Written exclusions are what make that test workable in advance. A scope that says on its face which conditions were not investigated tells everyone where the line sits before anyone is standing over a hole arguing about it.
The concrete owns the schedule, not the plumber
The repair itself is short. The sequence wrapped around it is not, and the sequence is what the schedule was built on.
Reaching a line under a slab means cutting concrete, trenching, removing and replacing the failed section, testing it, then holding everything open until it has been inspected. That inspection behaves the same way a structural one does — the work is proved while it can still be seen, and nothing that conceals it is released before the approval lands.
Then the trench gets backfilled, compacted and re-poured, and the calendar transfers from the plumbing contractor to the concrete. A new pour does not accept a bonded floor finish because the plumber has left; it accepts one when its moisture sits inside what the flooring manufacturer will warrant. That is a measurement rather than a date, and it catches people out, because it falls between two trades who both consider their part finished.
Everything sequenced behind that floor moves, and it moves by more than the length of the repair: the repair plus the inspection plus the drying plus whatever the following trades could not reschedule into. On a property carrying a construction loan or a lease commencement date, that arithmetic is the real cost of the condition, and it does not appear on the change order.
What turns a short trench into a long one
The things that extend this are mostly not plumbing. Start with what sits over the slab. Older resilient flooring and the adhesive beneath it can be a regulated material in a building of that age, and disturbing it is a compliance question with its own survey, its own licensed scope and its own timeline. Found after the cut it is a stop-work; found before, it is a line item.
The slab itself is the second problem. Conduit, another line, reinforcement, or in some construction a tensioned cable: locating before cutting is cheap and cutting blind is not. If the failed run passes near a footing or under a bearing wall, the excavation stops being plumbing and becomes a question for an engineer, because undermining bearing soil is a structural act regardless of why the hole was dug.
And the property has no drainage while any of this is open. On a house being turned that is a logistics problem. On an occupied one it is a habitability problem with a clock on it.
The work was not in the schedule of values. How does a lender-financed job pay for it?
It does not, until the schedule of values changes. A draw releases against line items the file already contains, and buried work is verified once and then covered permanently. So the approved change order has to enter the schedule of values, and the trench has to be photographed and measured while it is still open.
Billing the work against an adjacent line item is the shortcut, and it is the one that damages the file. It puts a request in front of an inspector who will compare it to a scope that does not describe it, and the result is usually a hold on the entire request rather than on the disputed part of it.
Where the money itself comes from is the lender’s answer to give, and it is a separate conversation from the construction one. What the construction side controls is how quickly a defensible number and a documented condition reach the people who decide.
Sequencing matters more here than on any other line. Everything else on the job stays verifiable for as long as it is visible; this is verifiable for an afternoon. A change order approved after the pour is a request to fund something no inspector can any longer see.
The evidence has an expiry date measured in hours
A schedule of values is a translation of a scope into something a loan can pay against. It was written from the scope that existed at closing, which means it holds no line for what is now sitting in the trench, and it will not hold one until somebody puts it there.
Meanwhile the condition itself is disappearing on a clock. What gets captured before the pour is the whole record, permanently:
- Photographs from several angles with something in frame for scale, before anything is removed
- The location marked against fixed points that will still exist when the floor is finished — a wall corner, a foundation edge, not a cabinet that is about to be installed
- The removed material retained until the change order is executed and the payment application on it has cleared
- The passed inspection recorded against the permit, so the file shows the work was authorised as well as performed
- The written notice and its date, which is the document that makes all of the above usable rather than merely interesting
None of that is administrative housekeeping. It is the only proof the work exists, and it stops being collectable the moment the concrete goes down. Owners running whole-property turns learn this once and then never skip it again, usually after carrying a repair on their own balance sheet because nothing in the file could establish it happened.
Converting the unknown before it becomes a change order
The same repair, discovered at two different moments, is two different contract events. Found during due diligence it is a line item — priced, sequenced, and inside the schedule of values before the loan closes. Found at demolition it is a change order: unpriced, unsequenced, and outside the file that funds the job.
Which of the two it turns out to be comes down to whether anybody looked. Scoping the drains on a property of that vintage is a small, targeted investigation, and it converts the most common concealed condition in South Florida housing stock from unknown into known before any capital is committed.
It improves the contingency conversation as well. Contingency attached to a named risk somebody tested and cleared is smaller than contingency floating against a general sense that old houses hide things. On an investment or repositioning project that difference shows up twice: as a tighter number to a partner, and as a schedule that survives being questioned.
If a property is under contract and its age puts this on the table, request a proposal and we will walk it, name what is unknown, and put the investigation into the scope rather than into next quarter’s change order log.