Two contractors look at the same bathroom and return proposals eleven thousand dollars apart. Both are polite, both showed up on time, both have a website with the same photographs of the same white subway tile. Nothing in either document explains the gap, and the homeowner is left choosing on instinct, or on price, which is instinct with a number attached.
The gap is usually real and usually explicable. It is just that almost everything driving it is invisible on the day the job is handed over — and stays invisible for several years, which is long enough for the wrong decision to feel like the right one.
This guide is the small set of questions that make the invisible part visible. Each has an answer that can be checked against a published standard or a public record, rather than against how confident the person sounds while answering it. None of them requires you to know anything about construction.
Why two bids for the same room differ by thousands
A bathroom is a small project with an unusually high proportion of concealed work. Waterproofing, slope, venting, blocking and electrical protection are all buried behind finished surfaces within days of being installed, and none of them can be inspected afterwards without demolition.
That produces an asymmetry that does not exist in most purchases. The contractor knows precisely which of those items they have priced. The homeowner cannot see any of them, cannot see their absence, and will not find out for somewhere between three and ten years. Meanwhile the visible items — tile, fixtures, glass, paint — are broadly comparable between bids, because those are the things a customer asks about.
So when a bid is sharpened to win a job, it is very rarely the tile that changes. It is the membrane specification, the fan and its ductwork, the slope beneath the pan, and the hours allowed for detailing corners and the drain connection. Every one of those is a genuine cost and none of them shows up in a photograph.
This is not an argument for choosing the most expensive proposal. It is an argument for making the concealed work explicit before you compare anything, so that the numbers in front of you describe the same job.
Four questions whose answers can be checked
Ask every contractor the same four. You are not testing whether they can answer — most can. You are testing whether the answer is specific, and whether it survives being written into the contract.
- Which waterproofing system, by name?
- A useful answer names an assembly: a bonded sheet membrane, a liquid-applied membrane meeting ANSI A118.10, or a traditional mortar bed with a pan liner. An answer that stops at "we waterproof everything" has told you nothing, because tile and grout are not waterproof and never were — the membrane behind them is what does the work. Ask for the system to be written into the scope.
- Where is the slope, and is there a pre-slope?
- Water that gets through grout has to reach the drain, which means the fall has to exist beneath the waterproofing and not only in the tile above it. On a mortar-bed installation that means a pre-slope under the pan liner. Omitting it is invisible, saves half a day, and leaves a permanent reservoir under the floor that no amount of cleaning resolves.
- What fan, and what duct?
- California sets local exhaust at 50 CFM on a demand-controlled switch, or 20 CFM running continuously. The number on the box is only half the answer — an adequate fan on a long, undersized, flexible duct moves very little air. Ask for the duct diameter, its run length, and where it terminates. "Into the attic" is not a termination.
- What is being blocked for, while the wall is open?
- Solid blocking behind the finished wall costs very little during framing and cannot be added afterwards without opening the wall again. Even if grab bars are not wanted now, a contractor who raises blocking unprompted is thinking about the room in ten years rather than on handover day.
What a complete proposal contains
Not a scoring system. These are the lines whose presence or absence tells you what kind of document you are holding.
| Line item | What a complete proposal says | What its absence usually means |
|---|---|---|
| Waterproofing | The system named, and the area it covers | The membrane is a line in someone’s head, not in the price |
| Ventilation | Fan model or rated CFM, duct size, route and termination | The existing fan is being reused whatever its condition |
| Allowances | A stated sum for tile, fixtures and fittings, with what happens if you exceed it | Selections will be priced later, when you are committed |
| Exclusions | What is explicitly not included — usually the honest part of the document | Everything unlisted becomes a change order |
| Unforeseen conditions | How rot, out-of-plumb framing or failed supply lines will be handled and priced | The first surprise becomes a negotiation while your bathroom is open |
| Permit | Who applies, who pays, and which office | Possibly nobody, which becomes your problem at resale |
| Payment schedule | Tied to work completed, within the statutory limits | Worth reading very carefully — see below |
A proposal listing four exclusions is not worse than one listing none. It is written by someone who has done this before and knows where projects go sideways.
What California actually allows a contractor to ask for up front
For a home improvement contract, the down payment may not exceed $1,000 or 10% of the contract price, whichever is less. Not whichever is greater, and there is no exception for special-order materials. Beyond that deposit it is unlawful to collect for work not yet performed or materials not yet delivered, and each progress payment may not exceed the value of what has actually been done. One narrow exception exists — a contractor holding a blanket performance and payment bond on file with the board may ask for more — and it applies to roughly two dozen companies statewide, so it is far more likely that a large deposit request is simply a large deposit request.
What the licence record tells you, and what it does not
The state licence lookup takes about two minutes and returns more than a yes or no. It shows whether the licence is active, which classifications it covers, whether the required bond is in place, and whether any complaints have been disclosed. A bathroom remodel generally sits under a general building classification, and a licence that is active but classified for something unrelated is a different conversation than a clean one.
It also tells you something before you look anything up. California requires the licence number to appear in a contractor’s advertising, so a company advertising without one is either unlicensed or careless about a rule that is trivial to follow. Neither is encouraging on a project where most of the work will be hidden behind a wall.
What the record cannot tell you is whether the work is any good. A clean licence is a floor, not a recommendation — it means the state has no reason to stop this person trading, which is a much weaker statement than it sounds. Treat it as a filter to apply before the conversation, not as evidence to rely on after it.
Signals that are actually diagnostic
Most advice about spotting a bad contractor is folklore. Turning up in an unmarked van proves nothing; plenty of excellent tradespeople drive unmarked vans. What follows is narrower, because each item is a decision the contractor made rather than a circumstance they are in.
Being talked out of the permit is the clearest one. The permit inspection is an independent check on precisely the concealed work you cannot evaluate yourself, so a proposal to skip it is a proposal to remove the only external verification in the process. The saving is real, small, and paid for later — at resale, when the record does not match the house, or during an insurance claim traced back to work with no record.
A second is a price that moves sharply when you hesitate. A number that drops several thousand dollars to close today was either padded before or is being cut somewhere now, and the place it gets cut is the concealed work. Estimating is not so imprecise that a correct price can fall by twenty per cent in a doorway.
A third is vagueness that survives a direct question. Asking which membrane will be used is not an unreasonable or technical request, and a contractor who deflects it twice is telling you either that the decision has not been made or that it is being left to whoever is on site that week.
The inverse is worth as much. Someone who volunteers what could go wrong behind the wall, prices a contingency for it, and writes down what happens if it appears, is describing a project they have run before rather than one they are hoping goes smoothly.
Running the comparison
Roughly an evening of work, most of which is waiting for people to reply.
Write the problem list first
Before any of this, write down what is actually wrong with the room — nowhere to put anything, cannot both use it, shower too small. Every bid should be tested against that list rather than against the others.
Look up each licence
Status, classification, bond, disclosed complaints. Two minutes each, before you spend an hour reading their proposal.
Send the same four questions to everyone
In writing, so the answers arrive in writing. Identical wording to each, so the replies are comparable rather than shaped by how you asked.
Normalise the scopes before the prices
Put the proposals side by side and mark what each includes. Where one is missing a line another has, ask for it to be priced rather than assuming it is covered. The bids are not comparable until the scopes are.
Read the payment schedule and the exclusions last
These are the two sections people skip and the two that determine what happens when something goes wrong. Check the deposit against the statutory limit while you are there.
Ask us the same questions
Everything above applies to us. We would rather be compared on a normalised scope than on a headline number, because the parts of a bathroom that make it last are the parts a sharpened bid removes, and we would rather explain what we have priced than quietly match someone who has not priced it.
If you want the four answers from us in writing before we ever visit, ask. They do not change depending on who is asking.
Questions we are asked about this
How many bids should I get?
Three is the usual advice and it is reasonable, but the number matters less than whether the scopes are comparable. Two proposals describing the same job tell you more than five describing five different jobs. If you can only normalise two, compare two.
Is the most expensive bid usually the best one?
No, and treating it that way is the mirror image of choosing on price. A higher number can reflect more included scope, higher-grade selections, a larger contingency, or simply higher overhead. The point of normalising scopes is that the comparison stops being about the number at all.
What if a contractor will not answer the technical questions in writing?
That is an answer. None of the four requires disclosing anything commercially sensitive — they are the specification, and the specification ends up in your house. Reluctance usually means the decision has not been made yet.
Can I ask for a bigger deposit to be reduced?
You can decline it outright. For a home improvement contract the limit is $1,000 or 10% of the contract price, whichever is less, and that is not a negotiating position — it is what the law permits. A contractor who insists on more without a blanket performance and payment bond on file is asking for something they are not entitled to.
Does a licensed contractor have to pull the permit?
The permit is normally taken out by the contractor performing the work, and that is the arrangement you want, because it puts responsibility for meeting code on the person doing the building. Where a homeowner pulls an owner-builder permit instead, that responsibility moves to them.
How do I check the work is being done as specified once it starts?
Photograph the walls before they close. Any competent contractor will expect it and many will offer. Photographs of the membrane, the blocking, the duct run and the electrical are the record you will want in five years, and the moment to take them lasts about a day.
Where to check this yourself
- Contractors State License Board(opens in a new tab)
Look up any contractor bidding your work. The public record shows licence status, classification, bond and any disclosed complaints — two minutes, before you sign anything.
- CSLB — Home Improvement Contracts(opens in a new tab)
What a home improvement contract must contain, the down payment limit, and the rule against collecting for work not yet performed.
- California Building Standards Commission(opens in a new tab)
Title 24, which is where the ventilation and permit requirements referenced here originate.
- Tile Council of North America(opens in a new tab)
Published methods for shower assemblies and the standards a waterproofing membrane is tested against.