When we asked 110 California homeowners about to start a remodel what they feared most, the budget came second, behind finding a contractor they could trust. They are the same fear. A remodel goes over budget for four reasons, and three of them are decided by how the contractor prices and runs the job, before a wall is opened. This article names the four, shows what each one costs and where it hides, and explains how a fixed-price design-build contract closes three of them and what to hold in reserve for the fourth. It is written for San Diego, where half the houses were built before 1980 and the fourth reason is a routine event.
Every figure here is from our own published pricing, our own survey, or a named public source. We do not publish totals or counts from our change orders, because we do not keep them as a data set; what we say about how often each cause appears is the experience of the people who run our projects, and it is labeled that way.
The fear, measured
In April 2026 we surveyed 110 single-family homeowners in California, all with household incomes above $200,000 and all scheduled to start construction within a year. Asked their biggest fear before starting, they put the contractor first and the budget second, with design decisions third and the timeline a distant fourth.
Those first two answers are one answer. Whether a budget holds depends on how the contractor built the number and how the contractor runs the job once the number is signed, which is why the rest of this article is about method rather than about saving money on tile. The full results are in our 2026 California remodel survey.
The four ways a budget breaks
Every overrun we have ever seen, on our projects or on the ones homeowners bring us after another contractor walked away, fits one of these four. They are listed in the order we see them most.
The most common and the least visible. A bid carries allowances for things not yet chosen, tile, plumbing fixtures, lighting, appliances, counters, set low enough to keep the total attractive. It excludes design, engineering, permits, or the finish work. It says "by owner" beside the painting. Nothing changed and the budget is already 20% short on the day it is signed.
The one no contract can prevent. Galvanized pipe, an undersized panel, aluminum wiring, a rotted subfloor, termite damage, no insulation, an unpermitted add-on from a previous owner. In a house built between 1950 and 1985 some of this is nearly certain, and a good firm looks for it before pricing and holds a contingency for the rest.
A wall "we were thinking about" opened after rough-in. A tile changed after the layout was set. A fixture moved after the plumber left. Each one is a change order with labor behind it, and each one is avoidable if the decision is made in design, where it costs a drawing instead of a crew.
An inspector requires additional GFCI or AFCI protection, ventilation to current code, fire-rated assemblies. An HOA wants a different exterior trim. A coastal lot carries height and view rules. These are predictable with the drawings and the HOA documents in hand before pricing, and surprises when they are not.
The bid you sign is the budget
Two contractors price the same kitchen. One writes a fixed price from a complete plan with every cabinet, counter, tile, fixture and appliance specified. The other writes a lower number with allowances for the items not yet chosen and leaves design, permits and painting out. The chart shows how the two numbers meet in the end, and which one the homeowner was told.
The allowance gap is not dishonesty, usually. It is what happens when a bid has to be written before the design is done, which is the order of operations in a bid-and-build project. Design-build reverses it: the design is finished and every selection made before the price, so the price covers the kitchen you are getting rather than the kitchen that makes the bid look good. What that price looks like for a kitchen is in our kitchen cost article, and for a bathroom in the bathroom cost article.
What the house hides, by the year it was built
The fourth cause is the one worth a chapter, because in San Diego it is the one most likely to happen to you. The table is what our production team expects to find behind the drywall by era; none of it is certain in any one house, and all of it is routine across the county's housing stock. Most of it is found in design, not in demolition, by walking the attic and the crawlspace, opening the panel and reading the permit history, and it is priced into the contract when it is found then.
| Built | What we expect to find | What it means for the budget |
|---|---|---|
| Before 1960 | Galvanized steel supply lines corroded inside, cast iron drains, knob-and-tube or cloth-wrapped wiring, a 60-amp panel, no insulation, undersized or notched framing, lead paint and asbestos in flooring and plaster | Plan on a re-pipe and a new panel when the kitchen or a bathroom opens; lead and asbestos work is by licensed abatement and priced before demolition |
| 1960 to 1979 | Aluminum branch wiring in houses from about 1965 to 1973, galvanized supply, 100-amp panels, Zinsco and Federal Pacific breaker panels, little or no wall insulation, termite damage in sill plates, asbestos in popcorn ceilings, vinyl flooring and joint compound, lead paint before 1978 | The most common era in San Diego and the one with the most to find; hold 10 to 15% on a whole home remodel |
| 1980 to 1995 | Polybutylene supply pipe, early ABS drain failures, panels at their limit for a new kitchen, unpermitted room additions and garage conversions from previous owners, water damage at decks and windows | A re-pipe is common; an unpermitted addition has to be legalized or disclosed, and legalizing it is a project of its own |
| After 1995 | Fewer systems surprises; water intrusion at windows and stucco, deck waterproofing, and the occasional DIY electrical from a previous owner | 5 to 10% is usually enough, more if walls are moving |
The contingency: how much, and who holds it
A contingency is the money you keep for the fourth cause. It is not part of the contract price and the contractor does not draw on it; it sits in your account until a written change order for a hidden condition needs it, and if none does, it is still yours. How much depends on the house's age and on how much of it the project opens.
Hold it even on a fixed-price contract. The fixed price covers the scope on the drawings; a 1972 house with a corroded galvanized line under the slab is not on the drawings, and when we find it, the choice is to fix it now with the floor open or to close the floor over it. The contingency is what lets a homeowner make that choice calmly. Our change orders guide explains how that conversation goes and what a healthy change order looks like on paper.
How our budgets hold: the method
None of this is a trick; it is the order the work is done in. The design is finished, every selection is made and every hidden condition we can reach is looked for before the price is written, so the price has nothing left to grow from except what no one could see.
Curious about how a stress-free remodel works when the owners are not even in town? One of our clients ran theirs from out of state on exactly this paperwork, and tells it in their own words.
The paperwork is the budget. Every project here has the same documents in the same order: the selections sheet signed before the contract, the contract with the scope and the exclusions listed by name, and then change orders, each one described, priced and approved before the work, so the running total is always one page. When a client asks me where they stand, I do not have to add anything up. That is what a budget that holds looks like from my desk.
Want a number that is the number?
A complimentary in-home design consultation is how it starts. A designer reads the house, hears what you want, and the price you sign is built from a finished plan with every selection on it, so the budget you set is the one you keep.
Red flags, and what a healthy change order looks like
- Says what changed and why, in a sentence a homeowner can read
- Is tied to code, safety, a city or HOA requirement, or your own request
- Shows the cost and the schedule effect before the work
- Carries your written approval, and the running total with it
- "Extra work" with no description
- A number with no breakdown
- Work done first, paperwork after
- A string of changes that design should have caught: moved outlets, a different tile, a wall that was "always going to" open
If a change order looks like the right-hand column, ask for it in writing before the work starts. A good remodeler has no trouble spelling it out, and in California a home improvement contract and its changes must be in writing in any case.
Before you sign: five things to settle
- Finish the design first. If the number arrives before the drawings and the selections, it is not the number. The timelines guide shows where design sits in the calendar and why it is not the place to save time.
- Read the exclusions and the allowances before the total. Seven questions above; the answers decide what the total means.
- Tell the contractor everything the house has done. Previous leaks, add-ons, the soft spot in the hall floor, the breaker that trips. Each one is a hidden condition found for free.
- Set the contingency and leave it alone. By the chart above, in your account, for the fourth cause only. It is not the upgrade fund.
- Decide the maybes now. The wall, the second sink, the skylight. Each is a drawing in design and a crew after demolition.
What each project costs when it is priced this way is in its own article: the kitchen, the bathroom, the whole home, the room addition and the ADU, and which of them pay back at resale is in which remodels pay back in San Diego.
How we built this article
The survey figures are from Kaminskiy's April 14 and 15, 2026 survey of 110 California single-family homeowners scheduled to start a remodel within a year, published on this site. The pricing is our own published pricing, the same figures in our cost articles. The hidden-conditions table is the experience of our production team by era, with the dates for aluminum branch wiring from the U.S. Consumer Product Safety Commission's guidance on repairing aluminum wiring and the lead paint date from the U.S. Environmental Protection Agency's Renovation, Repair and Painting rule, which applies to housing built before 1978. The contract rules are the Contractors State License Board's home improvement contract requirements. The contingency recommendations are ours. We do not publish counts or amounts from our change orders.
Sources read for this article (October 2026)
- Kaminskiy Design & Remodeling, California Home Remodel Survey 2026 (April 2026), and the change orders, kitchen cost, bathroom cost, whole home cost and timelines articles on this site.
- U.S. Consumer Product Safety Commission, Repairing Aluminum Wiring (publication 516).
- U.S. Environmental Protection Agency, Lead Renovation, Repair and Painting Program.
- Contractors State License Board of California, home improvement contract requirements, including the down payment limit.
- U.S. Census Bureau, American Community Survey 2024, year structure built, San Diego County.
Remodel budget overruns: your questions
Four reasons, in order of how often we see them. The bid was not the full price: it carried allowances for tile, fixtures, lighting or appliances that the real selections exceeded, or it excluded design, permits, engineering or finish work. The plan changed after demolition: a wall opened, a fixture moved after rough-in, a finish swapped late. The city or HOA required something the plan did not show: GFCI and AFCI protection, ventilation, fire-rated assemblies, exterior materials. And the house hid a condition that had to be corrected to build safely or pass inspection. The first three are closed by the contract and the drawings; the fourth is what a contingency is for.
It depends on the house and the scope. A cosmetic same-layout project in a house built after 1990, about 5%. A kitchen or bathroom that opens walls and moves plumbing or electrical, about 10%. A whole home remodel or structural work in a house built between 1950 and 1985, 10 to 15%, because galvanized pipe, undersized panels, aluminum wiring, missing insulation and hidden water or termite damage are routine finds in those years. The contingency is money you hold, not money the contractor prices in.
An allowance is a placeholder dollar amount for an item that has not been selected yet, such as $4,000 for tile or $10,000 for appliances. If the real selection costs more, the difference is added to the contract. Allowances are the most common reason a low bid ends high: the bid is compared on its total while the allowances inside it are set below what the finishes a homeowner actually chooses will cost. A fixed-price design-build contract makes every selection before the price so there is nothing left to allow for.
The usual list: galvanized steel supply lines that are corroded inside, cast iron drains, a 100-amp panel that cannot carry a new kitchen, aluminum branch wiring in houses from about 1965 to 1973, polybutylene supply pipe in houses from about 1978 to 1995, no insulation in exterior walls, termite damage in sill plates and framing, rotted subfloor under tubs and showers, and asbestos in flooring, ceiling texture and joint compound and lead paint in houses built before 1978. A good design-build firm looks for these before pricing, with an attic and crawlspace walk and a panel check, and prices what it can see.
A change order is a written amendment to the contract's scope, price or schedule. It is legitimate when it is for something you asked to add or change, something found inside the walls that has to be corrected for safety or code, or something the city or HOA required that the approved plans did not show, and when it is described, priced and approved by you in writing before the work is done. Our change orders guide covers what a healthy one looks like and what a red flag looks like.
It means the price for the scope you signed does not change. It can still change for the two reasons no contract can prevent: a condition the house hid that must be corrected, and a change you ask for. Both come as a written, priced change order you approve before the work. What a fixed price removes is the third source, the allowance and exclusion gap, which is the one that turns a $120,000 bid into a $150,000 kitchen without anyone having changed anything.
Line them up by what is included, not by the total. Check whether each one includes design, engineering, permits and plan check, demolition and disposal, every selection as a specified product rather than an allowance, electrical and plumbing to current code, and the finish work: paint, trim, hardware, final cleaning. Ask what happens if an allowance is exceeded and how change orders are priced. A bid that is 20% lower and carries five allowances and three exclusions is usually the more expensive one.
Ready when you are
