A range hood is only as effective as the system around it. The appliance has to overlap the cooking surface, move an appropriate amount of air, discharge through a workable duct path, receive the correct electrical supply, and remain serviceable after cabinets and finishes are complete. Hiring a range hood installation contractor is therefore a small mechanical project with kitchen-remodeling, electrical, ventilation, roofing or exterior-wall, and finish-carpentry interfaces—not merely a matter of hanging a box above a stove.
A useful proposal identifies those interfaces before demolition. It states the exact hood, blower arrangement, duct size and route, termination, mounting support, power connection, cabinet or enclosure work, permit responsibilities, protection, testing, and closeout documents. It also distinguishes known scope from allowances that depend on concealed conditions. That distinction lets homeowners compare bids on the same result instead of comparing one thorough contractor with another who has omitted the difficult parts.
This hiring guide explains what to request and verify. It does not select airflow, duct dimensions, clearances, makeup-air provisions, or electrical methods for a particular home. Those decisions depend on the listed appliance, cooking equipment, adopted codes, manufacturer instructions, building configuration, and local authority having jurisdiction. A qualified provider should resolve them in writing before work is concealed.
What a range hood installation contractor should include
The base scope should name the hood manufacturer and model, whether its blower is internal, inline, or exterior, and every accessory needed for the selected configuration. It should identify the cooking appliance below, the proposed mounting height, hood width and depth, and the relationship between the hood's capture area and the active burners. If the hood is an insert, the scope should also define who supplies and builds the approved liner or enclosure and how that enclosure provides access to filters, lights, controls, wiring, and blower components.
The ventilation portion should describe exterior discharge or explicitly state that the unit will operate in a manufacturer-approved recirculating configuration. For exterior discharge, require the proposed duct material, diameter or rectangular dimensions, route, transitions, elbows, joints, support, insulation or condensation treatment where applicable, and wall or roof cap. The agreement should prohibit unapproved size reductions and should assign patching and weatherproofing at every opening. “Connect to existing duct” is not an adequate description until the contractor has assessed that duct's size, material, condition, destination, and compatibility with the new appliance.
Mounting scope includes more than visible screws. The provider should confirm wall framing, cabinet capacity, ceiling blocking, island support, or another manufacturer-permitted substrate. The proposal should cover selective cabinet modification, finished panels, trim, backsplash cuts, fastener concealment, and repair of surfaces disturbed by investigation. If access requires removing a microwave, upper cabinet, soffit, ceiling finish, or roof covering, name the responsible trade and restoration standard.
Electrical scope should identify the branch-circuit or receptacle arrangement required by the hood instructions and adopted electrical rules. The proposal should state whether existing power will be reused, extended, or replaced; who performs that work; and whether a disconnect, junction box, dedicated circuit, or panel modification is included. Before the enclosure is closed, the installer should operate every blower speed, light setting, and accessible shutoff specified by the appliance instructions. This appliance-specific check is more useful than applying general lighting guidance to an integrated hood assembly.
Finally, the contract should include permits and inspections where required, floor and cabinet protection, dust control, debris removal, startup, airflow-related checks specified by the manufacturer, control and light testing, filter installation, owner orientation, photographs of concealed work, manuals, warranty registration responsibilities, and a written change-order process. The finished condition should be defined: operational, clean, securely mounted, externally weather-tight where penetrations were made, and accompanied by records—not merely “installed.”
When homeowners should consider hiring a range hood installation contractor
Professional planning is appropriate when a kitchen remodel changes the cooking appliance, cabinet layout, hood type, or location of the exhaust outlet. A larger range, a higher-output cooking surface, an island conversion, or a move from recirculation to exterior discharge can affect capture geometry, duct routing, electrical supply, and makeup air. Addressing the hood before cabinet drawings are released is usually more controllable than discovering after installation that a joist, plumbing stack, window, or upper cabinet blocks the intended route.
Homeowners should also seek a qualified assessment when the current hood is noisy but captures poorly, blows air back into the room, deposits grease on nearby cabinets, leaks cold air or water, vibrates, trips a breaker, or vents into an attic, crawlspace, soffit cavity, garage, or other interior location. Those symptoms do not prove one cause. Restricted ductwork, an unsuitable cap, excessive elbows, disconnected joints, poor capture area, incorrect blower setup, missing filters, pressure imbalance, or an appliance defect can produce overlapping results. A credible contractor investigates before prescribing replacement.
An installation deserves broader coordination when the proposed exhaust volume may trigger a code or design requirement for makeup air, when the home has naturally drafting combustion appliances, or when powerful exhaust devices operate together. The concern is not simply comfort. Exhaust can depressurize a tight home and alter airflow around fireplaces, water heaters, furnaces, dryers, bath fans, and other equipment. The responsible designer or contractor should evaluate the actual systems and applicable rules rather than relying on a universal airflow threshold quoted without jurisdictional context.
A contractor is especially important for island hoods and ceiling-mounted units, exterior or inline blowers, long or concealed duct runs, roof penetrations, masonry walls, historic finishes, complex cabinet inserts, and work near gas or electrical services. These conditions can require several trades and scheduled inspection points. Homeowners should not cut into an unknown wall or ceiling to “see where the duct might fit”; concealed wiring, piping, framing, asbestos-containing material, or structural components may be present.
Replacement can also be part of a safety correction. A cooking appliance that is unstable needs attention independent of the hood. The US Consumer Product Safety Commission's free-standing kitchen range safety material addresses range anti-tip protection and appliance-stability hazards. That evidence supports checking that a range remains properly secured and stable after adjacent work, but it does not provide hood sizing, duct design, or permission to modify the range. If the range rocks, tips, has a damaged cord or gas connection, or must be moved, assign that work to an appropriately qualified party.
How contractors assess the hood, duct route, power, mounting, and makeup air
A disciplined assessment starts with exact equipment data. The provider records the range or cooktop model, fuel and burner arrangement, overall width and depth, rear clearances, nearby combustibles, and the hood model under consideration. The contractor then checks the hood's published mounting-height range, permitted duct directions, required duct dimensions, electrical data, blower options, accessory list, filter type, and service clearances. A showroom label or retailer summary is not a substitute for the current installation manual.
Capture area is examined in plan and section. The provider compares the hood opening with the front and side extent of the cooking surface and considers whether cabinet faces, a deep backsplash ledge, an island cross-draft, or an unusually high mounting position will allow the cooking plume to escape. Airflow is not selected by a single rule of thumb. The contractor should document the basis used, then reconcile it with the hood instructions, cooking-equipment requirements, local code, noise goals, duct resistance, and the home's ventilation strategy.
Duct planning should occur before the final hood order when possible. The installer maps a continuous route to outdoors and verifies framing direction, available chases, cabinet space, attic or floor-system access, exterior clearances, and conflicts with plumbing, wiring, HVAC ducts, fire-resistance assemblies, and structural members. The route should minimize avoidable resistance while obeying the hood manufacturer's limits. The plan identifies every elbow and transition, the developed route, duct support, joint treatment, access, exterior penetration, and any need for insulation or condensation control.
Makeup-air assessment belongs beside—not after—blower selection. The provider inventories other exhaust devices and combustion appliances, reviews the applicable mechanical and fuel-gas provisions, and determines whether a designed supply, interlock, tempering strategy, or specialist evaluation is required. A contractor should be able to explain who owns this analysis and how its result affects the price. A bid that excludes makeup air without assessing whether it applies leaves a material scope gap.
For power, the electrical contractor or otherwise authorized person compares the hood nameplate and instructions with the existing circuit, conductor, grounding, overcurrent protection, receptacle or hardwire location, accessibility, and switching method. The assessment also checks whether a remote blower, makeup-air control, or proprietary control cable changes the rough-in. Power should not be improvised through an inaccessible extension cord or a junction buried behind fixed finishes.
Mounting investigation verifies the load path. Wall hoods may need framing or cabinet reinforcement; island hoods may require blocking above the ceiling and careful alignment with the cooktop; inserts rely on an enclosure built to the appliance's listing and instructions. The contractor should locate fasteners and access panels on drawings. If exploratory openings are needed, the proposal defines their size, protection, and repair.
The wall or roof cap is chosen as part of the system. Its connection size, damper, weather exposure, pest screen provisions where permitted, clearances from openings and other building features, finish, and flashing method must suit the actual location. Roof work should be coordinated with the roofing assembly and warranty requirements. Wall penetrations need a water-shedding tie-in to the exterior assembly, not a ring of surface sealant as the sole defense.
Before pricing is finalized, the provider checks permit and inspection requirements with the relevant jurisdiction. Commissioning then closes the loop: verify secure mounting, correct filters, damper movement, blower speeds, lights and controls, unusual noise or vibration, accessible service parts, and the manufacturer-required setup. Where the design calls for an interlocked makeup-air device, it should be tested through its intended operating sequence. The contractor records results and demonstrates normal operation to the owner.
Why fire, poor capture, grease buildup, excessive airflow, and unsafe vent termination change project scope
Fire-related conditions require a pause and a defined response. Heat damage, scorched cabinets, melted wiring, an appliance fire, grease inside an unsuitable duct, or inadequate clearance cannot be treated as cosmetic cleanup. The contractor should identify affected systems, isolate unsafe equipment, and involve the appropriate appliance, electrical, mechanical, restoration, or design professional. The range and hood manufacturer instructions, adopted rules, and findings from qualified inspection determine what can remain.
Poor capture can turn a nominal replacement into a layout problem. If the hood is too shallow, too narrow, unusually high, or exposed to strong cross-currents, simply fitting a larger blower may add noise without collecting the plume. The project may need a different hood geometry, cabinet modification, a lower permitted mounting position, or changes to the cooking and ventilation plan. Grease buildup similarly changes scope because accessible surfaces, filters, blower parts, and ductwork may need evaluation or cleaning before a new appliance is connected.
Excessive airflow is not automatically an upgrade. It can create objectionable sound, drafts, conditioned-air loss, pressure imbalance, and makeup-air obligations while still performing poorly through a restrictive duct. A contractor should not promise that the highest advertised airflow will solve every cooking complaint. The selected hood, duct, cap, controls, and building-air strategy need to function as one system.
An unsafe termination can require rerouting rather than reuse. Exhaust should not be discharged into a concealed interior space, and an exterior outlet may be unsuitable if it conflicts with manufacturer instructions or applicable clearance and weatherproofing requirements. A crushed cap, stuck damper, deteriorated roof flashing, or outlet placed where grease-laden air immediately soils or reenters the building can add exterior work. The revised estimate should state the new route, restoration, weatherproofing, access, and inspection implications.
Comparing wall-mount, under-cabinet, island, insert, downdraft, recirculating, and exterior-vented systems
Wall-mount hoods attach to a wall above a range or cooktop and often use a decorative chimney to conceal vertical ductwork. They can provide a clear capture canopy but may require removing upper cabinets, adding blocking, relocating wiring, and aligning the duct through a ceiling or rear wall. The contractor should verify that the decorative cover accommodates the actual ceiling height and elbows without obstructing service access.
Under-cabinet hoods preserve storage above the cooking surface and can discharge upward, rearward, or operate in a permitted recirculating mode depending on the model. Cabinet depth and construction affect capture and attachment. Existing cabinets may hide a narrow or improvised duct. A proper estimate covers cabinet cutouts, finished edges, shelf changes, support, power location, and the transition to the full required duct size.
Island hoods are exposed on all sides and depend on ceiling structure for support. Their capture geometry is sensitive to mounting height and room air movement. Installation commonly requires coordinated ceiling blocking, a carefully located vertical duct, power, and a finished chimney. Joists or trusses can prevent a straight route; cutting structural members without an approved design is not an acceptable workaround.
Inserts fit inside custom cabinetry or a built enclosure. They offer design flexibility, but the enclosure must meet the insert manufacturer's material, clearance, liner, opening, ventilation, attachment, and service requirements. Clarify whether the appliance installer or cabinetmaker owns dimensional accuracy. A handsome wood shell that blocks filter removal or traps heat is not a completed installation.
Downdraft systems pull air downward near the cooking surface, sometimes rising when used. They may suit an island where an overhead hood is impractical, yet their ductwork often competes with cabinet storage, floor framing, utilities, and toe-kick space. The contractor should evaluate the specific cooking equipment and downdraft pairing rather than assuming interchangeability. Floor or slab routing can make installation substantially more invasive.
Recirculating systems filter air and return it to the room. They avoid an exterior duct but do not provide the same removal path as an outdoor-ducted system. Filter type, replacement interval, availability, access, and the hood's approved conversion kit belong in the proposal. ENERGY STAR's discussion of indoor-air-quality features supports kitchen exhaust ventilation ducted outdoors as a way to remove cooking pollutants. That source supports the ventilation objective; it does not size a hood or declare that every existing home can accept a new exterior duct without project-specific design.
Exterior-vented systems carry captured air outside through a dedicated duct. Their performance depends on the complete route and termination, not just the hood label. They require space, envelope penetrations, weatherproofing, and assessment of makeup air and pressure effects. For many projects, the meaningful comparison is therefore not only appliance price: it is the installed system, including cabinet work, duct construction, cap, electrical work, controls, permits, restoration, testing, and future filter service.
Codes, permits, and manufacturer instructions for range hood installations
A contractor should identify the authority having jurisdiction and confirm which building, mechanical, electrical, fuel-gas, fire, energy, and residential provisions apply to the work. Requirements and adopted editions vary. Permit triggers can also depend on whether the project adds a duct, alters wiring, penetrates a roof, modifies structural framing, changes a gas appliance, or introduces makeup air. A generic internet summary is not a reliable substitute for the local determination.
Manufacturer instructions are part of the technical baseline. Obtain current documents for the hood, blower, liner, duct accessories, makeup-air equipment, cooking appliance, roof or wall cap, roofing product, and cabinet materials that form the enclosure. Record model numbers and revision dates. The contractor should resolve conflicts before installation—for example, when a cabinet drawing places the hood outside its permitted mounting-height range or when an existing duct is smaller than the hood's required outlet.
The proposal should state who applies for permits, schedules inspections, supplies access, corrects deficiencies, and delivers the approved final record. If no permit is required, ask the provider to document the jurisdictional basis rather than treating absence of a permit line item as proof. Permit approval does not transfer responsibility for following appliance instructions, and an inspection does not guarantee capture performance or workmanship beyond its scope.
Substitutions need written review. Changing the hood model can alter weight, mounting points, duct connection, airflow, power, chimney dimensions, makeup-air analysis, cabinet openings, and controls. Changing a roof cap or transition can affect resistance and weatherproofing. The change-order process should compare the replacement with the approved design and update drawings, price, schedule, manuals, and warranty information.
How a range hood contractor protects the home and occupants
Protection begins with a site plan. The contractor identifies work zones, material routes, occupied rooms, children and pets, smoke-alarm considerations, cooking shutdown, water or power interruptions, and safe daily cleanup. Floors, counters, appliances, cabinet faces, and adjacent finishes need coverings appropriate to cutting dust and dropped tools. Plastic sheeting alone is not adequate impact protection for stone counters or finished floors.
Dust control should match the materials being disturbed. Cutting cabinets, drywall, plaster, masonry, tile, and exterior finishes can produce different hazards. The contractor chooses extraction, isolation, respiratory protection, and cleanup methods and addresses any suspect lead-based paint, asbestos-containing material, mold, or fire residue through the applicable professional process. Homeowners should not be placed inside an active cutting or overhead-lifting zone.
Before drilling or cutting, the crew investigates utilities and structure. Power is made safe for authorized electrical work; gas appliances are moved or disconnected only by qualified parties; and concealed plumbing, wiring, ducts, and framing are located as far as reasonably possible. Roof and elevated exterior work require suitable access and fall protection. Openings are temporarily protected against rain, pests, and unauthorized access whenever the permanent cap cannot be completed the same day.
Range stability deserves an explicit closeout item when the appliance is moved. CPSC evidence in this brief supports the importance of anti-tip protection and appliance stability. The contractor should not remove or defeat an anti-tip device to gain access and then leave the range unsecured. The responsible appliance installer verifies the applicable bracket or restraint and confirms that cords, gas connectors, flooring, and adjacent cabinets were not damaged during repositioning.
Protection also means preserving ventilation safety during the transition. The crew should not leave a duct disconnected into a wall or attic, operate a hood before debris is cleared, or conceal electrical connections before required inspection. A final clean includes filters, accessible cabinet surfaces, counters, floor, and the area below exterior work. The provider should record pre-existing damage and completed repairs so responsibility is clear.
Range hood safety and performance checks before handoff
Before handoff, the contractor confirms that the hood is rigidly supported at its designated mounting points, aligned over the cooking surface, and installed within the manufacturer's permitted height range. Cabinet and enclosure clearances, liners, and service openings are checked against the approved model. Filters seat correctly and can be removed without dismantling finished cabinetry. Lights, controls, timers, heat sensors, and every blower speed are operated.
The duct path is inspected at accessible points for correct material, size, direction, supported joints, transitions, damper orientation, and obstructions. The exterior cap opens during operation and closes appropriately afterward. Roof or wall flashing and adjacent finishes receive a visual weatherproofing check. The contractor listens for contact, rattling, or vibration and investigates abnormal behavior instead of masking it with a lower speed setting.
Electrical covers and access panels are secured, grounding and circuit work are verified by the responsible electrical party, and no temporary cord or exposed connection remains. If a makeup-air or interlock system is part of the approved design, the provider demonstrates its response through all relevant hood settings. Combustion-safety or pressure testing, when required by the design or qualified professional, should be documented with the method, conditions, responsible person, and result.
The cooking appliance is returned to its intended position without pinched connections or damaged flooring. Its stability and anti-tip provision are verified by the responsible party. The handoff package includes models and serial numbers, permits and inspection status, concealed-work photos, control instructions, filter part numbers, cleaning limits, warranty documents, change orders, and unresolved exclusions. A homeowner should know whom to call for an appliance fault, duct problem, cabinet issue, exterior leak, or electrical concern.
What changes a range hood installation estimate
The range hood installation cost depends on far more than the hood's retail price. Labor changes with hood weight and type, mounting height, cabinet or enclosure construction, access, ceiling height, occupied-home protection, and the number of trades. An under-cabinet replacement on a verified compatible duct is a different project from an island hood requiring ceiling reinforcement, a new roof penetration, a remote blower, electrical relocation, and finished-plaster repair.
Duct scope can be the largest uncertainty. Price varies with route length, required duct size, elbows and transitions, framing conflicts, chase construction, fire-resistance details, insulation, accessibility, wall or roof material, cap selection, scaffolding, roofing coordination, and interior/exterior patching. Existing concealed ductwork may need camera inspection, selective opening, removal, or replacement if it is undersized, damaged, contaminated, disconnected, or routed to an unacceptable location.
Airflow decisions affect blower cost, sound-control options, duct size, power, cap, and possible makeup-air work. A designed makeup-air system can involve an outdoor intake, duct, damper, control or interlock, filtration, tempering, balancing, and coordination with HVAC or combustion equipment. The estimate should treat this as a defined system or a clearly stated design allowance—not a surprise discovered at final inspection.
Electrical price changes with circuit capacity, panel access, wall finish, distance, receptacle or junction location, remote-blower wiring, control integration, and permit needs. Finish work varies with cabinet modifications, matching panels, tile or slab backsplash cutting, paint, drywall or plaster, chimney-cover extensions, and repair around abandoned openings. Product lead times and custom color or metalwork can also alter schedule and mobilization.
A range hood installation estimate should separate fixed work, unit-price work, and allowances. Ask for assumptions about existing duct reuse, framing, hazardous materials, roof condition, circuit capacity, permit fees, working hours, and owner-supplied products. Require written approval before concealed-condition work proceeds. A low figure built on unverified reuse can become more expensive than a bid that funded investigation at the start.
Licensing, insurance, credentials, and crew questions for range hood work
A licensed range hood installer should identify the license classifications required where the home is located and for the actual work being performed. A general remodeling credential may not authorize electrical, mechanical, roofing, gas, or structural work. Ask which entity holds the prime contract, which trades are employees or subcontractors, who pulls each permit, and who supervises daily work. Confirm license status directly with the issuing body rather than relying on a logo or photocopy.
Request current general liability coverage and workers' compensation information appropriate to the crew arrangement, then confirm it through the insurer or agent when warranted. Automobile or umbrella coverage may matter for larger projects, but insurance is not a substitute for competence. The contract should identify the legal business name, physical contact information, responsible license holder, and dispute or change procedures.
Experience questions should be specific: How many installations involved this hood type, an insert enclosure, an island mount, an exterior blower, or makeup air? Who measures the duct route? Who resolves cabinet and appliance-manual conflicts? What hold points are photographed? How are roof or wall penetrations flashed? What happens if framing blocks the route? Ask to see a redacted sample scope and closeout package, not only polished finished-kitchen photographs.
References and reviews are useful when interpreted carefully. Seek recent projects with comparable complexity and ask whether the original estimate identified exclusions, trades arrived in sequence, changes were documented before work, dust was controlled, inspections passed, and warranty calls were answered. Range hood installer reviews cannot prove code compliance or the condition of a concealed duct, but patterns in communication and correction practices can inform hiring.
Crew questions should establish authority on site. Know who may stop work, approve a technical substitution, energize the appliance, move the range, access the roof, and sign the commissioning record. Language access and owner communication should be planned. If separate cabinet, electrical, HVAC, roofing, and appliance teams are involved, the schedule should name the coordinator rather than leaving each trade to assume another owns the gap.
Range hood product and workmanship warranty checkpoints
Separate the appliance manufacturer's warranty from installer labor and contractor workmanship coverage. The product warranty may exclude installation errors, improper ducting, unauthorized modification, commercial use, missing registration, or damage caused by other trades. Ask who registers the appliance, keeps the serial number, handles a dead-on-arrival unit, pays for removal needed to access it, and coordinates replacement when the hood was owner supplied.
A range hood installation warranty should define duration, covered work, response process, exclusions, transferability, and the remedy. Duct joints, mounting, cabinet modifications, finish repairs, electrical work, and exterior penetrations may be warranted by different parties. The prime agreement should still give the homeowner one clear route for reporting a symptom and determining ownership. “Manufacturer warranty applies” leaves installation workmanship undefined.
Preserve conditions needed to keep warranties valid. That includes model and serial labels, purchase records, permits, inspection approvals, approved accessories, filters, cleaning instructions, concealed-work photographs, and documentation of any manufacturer technical-support decision. Do not let a contractor discard a required damper, modify an enclosure, reduce a duct, or alter wiring on the theory that the change is invisible after completion.
Warranty checkpoints should address water entry at the new roof or wall penetration, vibration or loosening, inaccessible filters or controls, cabinet finish damage, nuisance electrical behavior, and makeup-air control faults. Normal filter replacement, grease cleaning, lamp replacement where user-serviceable, and appliance-component failures may be owner or manufacturer responsibilities. The handoff should distinguish maintenance from covered correction before a problem occurs.
Range hood contractor hiring checklist
- Record the exact hood, blower, cooking appliance, liner, control, filter, duct accessory, and cap models before accepting a proposal.
- Require a drawing or written route showing duct size, material, elbows, transitions, supports, exterior termination, and restoration.
- Confirm hood width, depth, capture relationship, mounting-height range, and cabinet or enclosure dimensions from current instructions.
- Ask who evaluates airflow, duct resistance, simultaneous exhaust, combustion appliances, and any makeup-air requirement.
- Verify mounting support and identify any wall, ceiling, cabinet, or structural investigation needed before installation.
- Define electrical scope, circuit assumptions, remote-blower or interlock wiring, permits, and the authorized electrical provider.
- Confirm the range remains stable and its applicable anti-tip protection is restored after any movement.
- Assign roof or wall penetration, flashing, weatherproofing, exterior finish, cabinet, backsplash, drywall, paint, and cleanup work.
- Check license classifications, active status, insurance, subcontractors, supervisor, and responsibility for permits and inspections.
- Compare installed-system costs by included scope and assumptions, not by the appliance-and-labor total alone.
- Obtain a range hood installation estimate with fixed items, allowances, exclusions, unit prices, and written change approval.
- Ask for the commissioning checklist: controls, lights, speeds, damper, cap, vibration, filters, access, and makeup-air sequence.
- Require manuals, model and serial records, filter information, concealed photos, approvals, warranty terms, and contact ownership.
- Reject proposals that promise reuse of unseen ductwork or quote a “standard install” without assessing the actual kitchen.
During a range hood installation consultation, ask the provider to trace the whole air path aloud: from the front burner into the capture area, through the blower and each duct section, past the damper, and out the cap. Then ask where replacement air comes from, how the hood is supported, which circuit serves it, and who restores every surface crossed by the route. Clear, model-specific answers reveal whether the provider has priced a system or only an appliance mounting.
The strongest range hood installation scope is inspectable before, during, and after the work. It defines equipment and assumptions before ordering, uses hold points before duct and wiring disappear, and ends with functional checks and documents. That structure protects both parties: the homeowner can compare a licensed provider on evidence, while the contractor has a written basis for handling concealed conditions without improvising behind finished cabinetry.