Unknowns and contingency
What is still unknown about your building, and what that reserve is worth
A flat ten per cent contingency is a confession that nobody looked. Two kitchens with identical budgets can carry completely different risk, and the difference is not luck — it is a list of specific, nameable things that are currently unknown about the building. This page enumerates yours and derives the reserve from them.
What your building has not told you yet
Derived contingency
$15,428
6 unresolved unknowns, 2 of them capable of changing the size of the job rather than its price. Weighted by severity, that derives a reserve of 26.6 percent, or $15,428 on a $58,000 subtotal.
6 of these can be closed before a single contractor writes a number, and every one you close takes its own weight out of the reserve above. That is the actual mechanism by which a contingency gets smaller: not by negotiating it down, but by turning unknowns into knowns.
Your unknowns, one at a time
Ungrounded circuits feeding the kitchen — material
Why it is on your list. You identified ungrounded two-wire circuits.
What goes wrong. New kitchen receptacles need a ground path. Without one, the electrician is running new home runs rather than extending what is there, and the panel needs the spaces for them.
How to close it before anyone bids. A three-dollar receptacle tester answers this in ten minutes.
Galvanised supply piping — severe
Why it is on your list. You identified galvanised or mixed supply piping.
What goes wrong. Galvanised pipe corrodes from the inside and frequently cannot be cut and re-threaded without the adjacent section failing. A sink move becomes a supply replacement back to a sound connection point, and where that point is cannot be known until it is cut.
How to close it before anyone bids. Ask the plumber to cut one accessible section and look at the bore. The inside diameter tells you more than the outside ever will.
Plaster over wood lath rather than drywall — material
Why it is on your list. You identified plaster on lath.
What goes wrong. Plaster demolition takes roughly twice the labour of drywall and produces far more debris. Patching plaster to a flat, paint-ready plane next to a new drywall section is a specialist skill that not every crew has.
How to close it before anyone bids. Remove one receptacle cover plate and look at the cut edge.
Pre-1980 materials disturbed by demolition — severe
Why it is on your list. The house dates from 1948 and walls are being opened to the studs.
What goes wrong. Sheet flooring, mastic, joint compound and pipe insulation from this era can require testing before demolition and licensed handling afterwards. Discovering it mid-demolition stops the job while a lab result comes back.
How to close it before anyone bids. Have samples taken and tested before the crew mobilises. A test costs a fraction of a stopped job and the result is good for the whole project.
Out-of-level floor under new cabinets — material
Why it is on your list. You reported the floor feels uneven.
What goes wrong. Cabinets are shimmed to level, not to the floor. A significant slope means tall shims, a visible gap at the toe kick, and a countertop that reads crooked against a level wall line. Correcting the floor is a separate scope from the kitchen.
How to close it before anyone bids. Put a long level or a laser across the room in both directions and write the worst deviation down. That single measurement changes several bids.
Earlier work with no permit record — material
Why it is on your list. The permit history has not been checked.
What goes wrong. An inspector who finds unpermitted work adjacent to your scope can require it to be brought into compliance before signing off the work you actually wanted, and that requirement is not negotiable at the point it is issued.
How to close it before anyone bids. Most jurisdictions publish the permit history for an address online or over the counter, free. Look before you file, not after.
How a contingency is supposed to shrink
A contingency is not negotiated down. It shrinks when unknowns become knowns, and every item above with a closing action attached is an unknown you can convert for the price of an afternoon. That is the entire mechanism, and it is available to a homeowner without any trade skill at all.
- Look at what you can see. A receptacle cover plate, the cut edge of a wall, the pipe under the sink, the label on a joist. Four observations settle four items on most lists.
- Pull the permit history. Most jurisdictions publish it free, and it takes a search rather than a request.
- Put a level across the floor in both directions and write down the worst deviation. One measurement, several bids affected.
- If the house predates 1980 and walls are opening, get materials tested before mobilisation rather than during demolition. The result is good for the whole job and a stopped job is not.
- Then re-run this page. Watch the reserve fall as each unknown turns into a known, and take the difference back into the budget deliberately.
What to put in the contract about all this
- A written allowance for exploratory opening, so nobody is negotiating in the middle of a demolition day.
- An agreed hourly rate and markup for genuinely unforeseen work, set before it is needed rather than after.
- A requirement that any change over an agreed threshold is documented and signed before the work happens, not billed after it.
- A clear statement of who pays for delay caused by an inspection failure, and who pays for delay caused by a late material order.
- Photographs of every wall and floor cavity before it is closed up, which cost nothing and settle every future argument about what is behind the finish.