How to Choose a Shower Remodeling Contractor in Denver: A Vetting Guide

A badly set kitchen floor shows itself: lippage, hollow tiles, crooked lines. A badly built shower can look perfect for months. Tile and grout shed most of the water but are not the waterproofing, as we explain in Tile and Grout Are Not Waterproofing. The membrane or liner, the slope beneath it, the drain connection and the sealant at every change of plane are the shower. The tile is the finish.

That hidden work gets one test. The model plumbing code (the International Residential Code, adopted by metro jurisdictions in different editions with local amendments) requires the completed liner to be flood tested: drain plugged, water at least 2 inches deep at the threshold, held at least 15 minutes, with no evidence of leakage. After tile, the only test left is time, and failures often show up first on the ceiling below. What Causes a Shower Pan to Fail covers why.

References and finished photos tell you a contractor can make a shower look good. You need to know what they do on the days nobody sees.

None of these are trick questions, and a contractor who builds showers for a living will answer them without hesitating. Listen less for vocabulary than for a system.

Two answers are worth seeing rather than hearing: how high the liner goes, and the slope under it.

Homeowners often ask for a "Colorado contractor license number." For a tile or remodeling contractor there is none to give: Colorado licenses plumbers and electricians at the state level and leaves building contractor licensing to cities and counties. The Attorney General's consumer site says to "check with your city or county to make sure the general contractor is licensed to work in your area" and to search plumbing and electrical licenses through the Department of Regulatory Agencies (DORA). Local licenses do not travel, either: Denver does not accept or reciprocate contractor licenses from other counties or states.

Other metro cities and counties set their own rules, so ask what your address requires and whose name the permit will be under. Our guide to bathroom remodel permits in Aurora, Parker and Denver covers the permit side.

Insurance: what to ask for

The FTC's Hiring a Contractor guide lists personal liability, worker's compensation and property damage coverage, and says to "ask for copies of insurance certificates, and make sure they're current, or you could be held liable for any injuries and damages that occur during the project." The NAHB's hiring checklist names workers' compensation and general liability.

A certificate of insurance is a one-page summary issued by the insurer: the insurance company, the contractor's legal business name, coverage types, policy numbers, effective dates and limits. Check that the dates cover your project and the name matches your contract. Our suggestion: have the agent send it to you directly, with you listed as certificate holder. Parker's registration page links a "Statement of Exemption from Workers Compensation Law," so not every registered contractor carries that coverage; if yours does not, ask who pays if a helper is hurt in your home.

Beyond local and state trade licenses, no credential is required to build a shower in Colorado, and many good shower builders hold none of these. Treat them as evidence, not a filter.

• Certified Tile Installer (CTI). Run by the Ceramic Tile Education Foundation. Candidates need two years as a full-time lead installer, then pass a 155-question open-book exam and a hands-on test covering layout, membranes, backer board, tile, grout and sealant. CTEF publishes a directory, so the claim is checkable. It certifies a person: ask whether that person will set your tile.
• Advanced Certifications for Tile Installers (ACT). Also CTEF, for pre-qualified installers in seven areas; three matter here: Membranes, Shower Receptors, and Large Format Tile & Substrate Preparation.
• NTCA membership. A 2025 TileLetter article describes the National Tile Contractors Association as "the world's largest tile trade organization," with a mission of installation training and education. Membership is an affiliation, not a test of the installer; ask what training the person setting your tile has taken.
• TCNA Handbook. The Tile Council of North America calls its Handbook "a guide to assist in clarifying and standardizing installation specifications for tile," including wet-area guidelines and workmanship standards excerpted from ANSI. A contractor who can name the method your shower follows is building to a documented system.

Know which kind of rule you are hearing. The flood test and liner height are building code; ANSI A118.10 membranes and ASTM C920 sealants are industry standards; the 95% coverage figure is a manufacturer instruction; "we flood test every shower" is company practice. A good contractor knows the difference.

Finished photos prove someone can set tile. The photos that prove they can build a shower are the ones nobody frames: membrane before tile, the liner behind the bottom rows, the pre-slope, a pan holding water. The NAHB says to ask to see work "both completed and in progress," and the FTC suggests visiting jobs in progress.

The FTC says a contractor should be able to give you at least three clients with projects like yours, and suggests asking how long ago the work was done, whether it finished on time and whether there were unexpected costs. For a shower, call one from a year or more back and ask about stains on the ceiling below.

On a Google Business Profile, read past the star average. Look for specifics, such as waterproofing, a flood test, or a problem that was found and how it was priced, and read the low reviews and the owner's replies: that is how criticism of your job would be handled. The FTC suggests searching the company name with words like "complaint" and "review" and reading reviews critically.

A one-line "shower remodel, $X" quote cannot be compared with anything. The FTC suggests written estimates from several contractors, not automatically the lowest, and asking why they differ. A readable shower quote itemizes:

• Demolition and disposal.
• The waterproofing system by name, the pan type, and the flood test as a step.
• Framing or subfloor repair as an allowance, with the rate if it is exceeded.
• Plumbing and electrical: who does it, and whether permit fees are included.
• Tile material separately from labor; if it is an allowance, the budget for each item.
• Grout, sealant, trims, edge treatment, niche and bench.
• Exclusions in writing, such as paint, flooring outside the shower, or the ceiling below.

The cost drivers in Bathroom Remodeling Costs in Denver: What Affects the Price? and the tiers in Essential vs. Premium Shower Remodeling Options are easier to compare when every quote is itemized this way.

The contract

The FTC's guide says a contract should include the contractor's name, address, phone and license number (if required); estimated start and completion dates; the payment schedule; the contractor's obligation to get all necessary permits; how change orders are handled; a detailed materials list, with any allowances; warranty information; what the contractor will and won't do; promises made in conversation; and, if you signed at home or anywhere other than the seller's permanent place of business, your right to cancel within three business days. For a shower, also name the waterproofing system and the flood test.

On payment, the FTC says don't pay cash, limit the down payment, tie payments to completed work, and never make the final payment until the work is done and you're satisfied. Colorado's Attorney General lists "asking for more than 10% of costs up front" among contractor warning signs.

Before the final payment, the FTC also says to confirm that subcontractors and suppliers have been paid, because state law may let them file a mechanic's lien against your home, and to ask the contractor and every subcontractor and supplier for a lien waiver. Colorado's lien statute gives the owner of an existing single-family home an affirmative defense once the full contract amount plus change orders has been paid to the principal contractor. We are not lawyers: collect the waivers, and call an attorney if a lien appears.

What a "lifetime warranty" covers

Read the document, not the ad. The FTC says the contract should name who honors each warranty (contractor, distributor or manufacturer), its length and its limitations; that anything not listed should be assumed not covered; and that spoken promises belong in writing. Ask: lifetime of what? Labor or only materials? Water damage below? What voids it? Is it transferable? No warranty substitutes for a flood test.

• "Tile is waterproof," or grout sealer described as the waterproofing.
• No flood test. The code requires one for lined receptors; skipping it asks you to take their word for the one thing that can be checked.
• No named membrane. "Waterproofing" is a category, not a product.
• No permit for a drain or valve move, or asking you to pull it. The FTC lists the second as a warning sign; the Attorney General lists "refusing to pull required local permits."
• Cash only, gift cards, cryptocurrency, or a large deposit. The FTC and the Attorney General both flag cash demands and large up-front payments.
• Door-to-door selling or pressure to sign today.
• No certificate of insurance, or one in a different business name.
• "We'll handle anything we find," with no written change-order process.
• Only finished photos.

For what "anything we find" can mean, see What We Found After Shower Demolition. The right response to a surprise is a photo, a conversation and a priced change order, in that order.

Before you sign, every line should be a yes.

1. The waterproofing system and pan type are named in writing.
2. There is slope under the liner or membrane.
3. Every shower is flood tested, and you can watch or get photos.
4. The liner rises at least 2 inches above the threshold.
5. Changes of plane get ASTM C920 sealant, not grout.
6. Large tile gets an ANSI A118.15 mortar with coverage checked.
7. The permit, the jurisdiction and who pulls it are named.
8. You verified the local license and any state plumbing or electrical license.
9. You hold a current certificate of insurance in the contracting business's name.
10. You have seen in-progress photos and called a reference from a year or more ago.
11. The quote is itemized, with allowances and exclusions in writing.
12. The contract names dates, milestones, the change-order rule and warranty terms.
13. The deposit is modest, and you will collect lien waivers with each payment.

Deciding whether to repair or replace first? Start with Shower Repair vs. Complete Rebuild.

Does a shower contractor need a license in Colorado?

Not from the state for tile and general construction. Plumbing and electrical work requires state licenses issued through DORA. Building contractor licensing is local: Denver issues its own and does not reciprocate, Aurora licenses contractors and supervisors, and Parker requires every contractor to be licensed with the Town. Check the rule for your address.

Should I hire a tile setter or a general contractor?

Either can work. What matters is that one person owns the waterproofing from the drain to the top of the wall, and that plumbing is done by a state-licensed plumber. Split jobs fail at the gaps: a drain the tile setter did not plan for, or backer board everyone assumed someone else waterproofed. Ask who owns the membrane and the flood test. The answer should be a name.

How big a deposit is normal?

Colorado's Attorney General treats more than 10% up front as a warning sign, and the FTC says to limit the down payment and tie payments to completed work. Sensible shower milestones: demolition done; waterproofing done and flood tested; tile done; glass installed. The final payment follows your walkthrough.

The contractor says a bonded membrane doesn't need a flood test. True?

Ask them to test anyway. The code's liner test applies to receptors made watertight with the materials it lists, and bonded membranes meeting ANSI A118.10 are on that list. A bonded membrane still has seams, corners and a drain connection, and a test needs only a plug, water and time. We flood test every shower we build, whatever the system.