Commercial Kitchen Build-Out Guide for Contractors | Projul

Commercial kitchen build-outs are a different animal. If you have been running residential remodels or standard commercial tenant improvements, stepping into a restaurant kitchen project will test every part of your operation. The mechanical systems are more involved. The code requirements are stricter. The inspections are more frequent. And the owner is usually on a tight timeline because every week without a working kitchen is a week without revenue.

This guide breaks down the six areas you need to get right on a commercial kitchen build-out. Whether you are a GC taking on your first restaurant project or an experienced contractor looking for a reference, this will help you plan the work and avoid the mistakes that blow budgets and timelines.

Health Department Requirements and Code Compliance

Before you pull a single permit, you need to understand that commercial kitchens answer to more than just the building department. The health department has its own plan review process, its own set of requirements, and its own inspection schedule. In many jurisdictions, you cannot get a certificate of occupancy without a health department sign-off, and their standards go well beyond what the building code requires.

Health department requirements vary by state and county, but here are the items that show up on nearly every project:

• Floor, wall, and ceiling finishes must be smooth, non-absorbent, and easy to clean. FRP panels, epoxy-coated concrete, and commercial-grade tile are the standard choices. Drywall with paint alone will not pass in most kitchens.
• Handwash stations are required at specific locations throughout the kitchen, typically near each food prep area and at every entrance to the kitchen from other parts of the building. These are separate from your three-compartment sinks and cannot be used for food prep or dishwashing.
• Floor drains with proper slope are required in areas where water accumulates, including near dishwashers, under three-compartment sinks, and in walk-in cooler areas. Most health codes require a minimum 1/8-inch per foot slope to drains.
• Temperature-controlled storage requirements dictate minimum and maximum distances between cooking equipment and refrigeration, walk-in cooler door clearances, and ventilation around reach-in units.
• Pest control provisions include sealed penetrations, self-closing doors, and air curtains at exterior openings. The health department will check every pipe penetration, conduit entry, and gap under doors.

The biggest mistake contractors make with health department requirements is treating them as an afterthought. Get the health department plan review started at the same time you submit for your building permit. Running these in parallel can save you weeks on the front end. If you are tracking multiple permit timelines, a system like Projul helps you keep everything visible so nothing falls through the cracks. For more on managing the permit process, check out our construction permit tracking guide.

Work closely with the owner’s kitchen consultant or food service designer. They should be producing a kitchen layout that already accounts for health code requirements, but verify everything against your local code before you start building. Health departments are not known for being flexible during inspections.

Hood and Ventilation System Design and Installation

The exhaust hood and ventilation system is the heart of a commercial kitchen build-out, and it is usually the single most expensive mechanical system on the project. Getting this right requires coordination between your mechanical engineer, your HVAC sub, your fire suppression contractor, and the equipment supplier.

Commercial kitchen exhaust hoods fall into two categories:

Type I hoods are required over any cooking equipment that produces grease-laden vapors. This includes fryers, grills, charbroilers, ranges, and most ovens. Type I hoods require a fire suppression system (typically an Ansul or similar wet chemical system), grease-rated ductwork, and specific exhaust rates measured in cubic feet per minute (CFM).

Type II hoods are used over equipment that produces heat and moisture but not grease, such as dishwashers, steam tables, and some ovens. These are simpler systems without fire suppression requirements but still need proper exhaust calculations.

Here is what you need to nail on the ventilation scope:

• Exhaust CFM calculations are based on the hood size, equipment type, and cooking volume. Your mechanical engineer sizes this based on ASHRAE 154 or IMC Chapter 5 requirements. Undersizing the exhaust is a code violation and a safety hazard. Oversizing it wastes energy and creates negative pressure problems.
• Make-up air is the supply air that replaces what the exhaust system pulls out. Without adequate make-up air, you get doors that are hard to open, drafts that pull conditioned air from the dining room, and pilot lights that blow out. The make-up air system needs to be designed alongside the exhaust, not added later.
• Ductwork routing matters more than most contractors realize. Grease-rated ductwork has specific requirements for material gauge, joint construction, slope, and cleanout access. The duct run should be as short and straight as possible, and it must terminate through the roof (not a side wall in most jurisdictions). Plan the routing during preconstruction so you are not field-engineering around structural members and other trades.
• Roof penetrations and curbs for exhaust fans need to be coordinated with the roofing contractor. If you are working in a multi-tenant building, there may be landlord requirements about fan placement, noise levels, and grease exhaust locations relative to other tenants’ HVAC intakes.

Budget 15 to 25 percent of your total project cost for the hood and ventilation system. On a $300,000 kitchen build-out, that means $45,000 to $75,000 just for the exhaust and make-up air package. Get your mechanical sub involved early and make sure their bid includes the fire suppression system, controls, and commissioning.

For tips on coordinating multiple subcontractors on a project like this, take a look at our guide on managing subcontractors and our post on construction crew scheduling.

Grease Trap and Interceptor Installation

Every commercial kitchen that produces fats, oils, and grease (FOG) needs a grease interceptor. This is not optional. Your local sewer authority and the health department both require it, and the penalties for non-compliance include fines, shutdowns, and liability for sewer line blockages.

There are two main types of grease interceptors:

Point-of-use grease traps are small units (typically 20 to 50 GPM) installed under or near individual fixtures like three-compartment sinks and dishwashers. These are more common in smaller kitchens and retrofit situations where exterior installation is not practical.

In-ground grease interceptors are large concrete or fiberglass vaults installed outside the building, usually in the parking lot or service area. These handle higher flow rates (50 to 200+ GPM) and are required on most full-service restaurant projects. They need to be sized based on the total number of fixtures, the drainage fixture unit count, and local code requirements.

Key considerations for your grease trap scope:

• Sizing matters. An undersized grease trap will overflow, cause backups, and fail inspection. Work with your plumbing sub to run the calculations based on PDI (Plumbing and Drainage Institute) standards or your local code requirements. Most jurisdictions have a specific formula based on fixture count and flow rate.
• Location and access. In-ground interceptors need to be accessible for regular pump-outs (typically every 30 to 90 days depending on the jurisdiction and kitchen volume). Do not bury them under pavement without accessible covers, and make sure the pump truck can reach them.
• Venting. Grease interceptors produce hydrogen sulfide gas and need proper venting per plumbing code. This is a detail that gets missed on projects where the site work sub installs the interceptor and the plumber handles the interior piping. Make sure someone owns the vent connection.
• Sampling ports. Many sewer authorities require sampling ports on the discharge side of the interceptor so they can test your effluent. Verify this requirement before you pour concrete.
• Coordination with site work. If you are installing an in-ground interceptor, this needs to happen during your site work phase, before you pave. Coordinate the excavation, vault placement, piping connections, and backfill with your site work sub and plumber simultaneously.

Grease interceptor costs range from $2,000 to $5,000 for a point-of-use trap up to $15,000 to $40,000 for a large in-ground vault including excavation, installation, and piping connections. Factor in the ongoing maintenance cost when discussing options with the owner, since this is their long-term operating expense.

Electrical and Plumbing Rough-In Considerations

Commercial kitchens have electrical and plumbing demands that dwarf typical commercial tenant improvements. If you are used to bidding standard office build-outs, the utility requirements on a restaurant project will be a wake-up call.

Electrical

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A commercial kitchen typically requires 200 to 600 amps of service depending on the equipment package. A single commercial convection oven can pull 50 amps. A six-burner range with oven draws 40 to 60 amps. Walk-in coolers and freezers each need dedicated circuits. And that is before you add the dishwasher, hood exhaust fans, make-up air unit, and lighting.

Here is what to plan for:

• Service upgrade. Verify the existing electrical service early. Many older buildings have 200-amp service, which is not enough for a full commercial kitchen. A service upgrade to 400 or 600 amps means coordinating with the utility company, which adds lead time and cost.
• Three-phase power. Most commercial kitchen equipment runs on three-phase power (208V or 480V). If the building only has single-phase service, you are looking at a transformer installation or a utility upgrade. This is a project-killer if you discover it late.
• Dedicated circuits. Every major piece of equipment needs its own dedicated circuit. Your electrical sub should get a copy of the equipment schedule with voltage, amperage, and phase requirements for every piece of equipment before they start their bid.
• Emergency circuits and GFCI. Health codes require GFCI protection on outlets within six feet of water sources. Emergency lighting and exit signs need to be on a separate circuit with battery backup. Do not forget the hood fire suppression system’s electrical connection and the gas shut-off solenoid.
• Conduit routing. Plan conduit runs to avoid conflicts with plumbing, mechanical ductwork, and the hood system. In a commercial kitchen with an 8-foot ceiling, space above the ceiling grid gets crowded fast. A detailed coordination drawing saves time and change orders.

Plumbing

The plumbing scope on a commercial kitchen includes hot and cold water supply, waste and vent piping, gas piping, floor drains, grease waste lines, and indirect waste connections. Here are the items that catch contractors off guard:

• Gas piping. Most commercial cooking equipment runs on natural gas. The gas piping system needs to be sized for the total BTU load of all connected equipment, with proper pressure regulation and shut-off valves at each appliance. Your plumber needs the full equipment schedule with BTU ratings before they can size the gas line from the meter.
• Hot water capacity. A commercial dishwasher needs 180-degree water for the final sanitizing rinse. Most buildings do not have a water heater that can support this. Plan for a dedicated commercial water heater or booster heater sized for the dishwasher’s demand plus the rest of the kitchen’s hot water needs.
• Indirect waste connections. Health codes require that certain equipment (ice machines, walk-in cooler condensate drains, commercial dishwashers) discharge through an air gap rather than a direct connection. This prevents backflow contamination. Your plumber needs to know which fixtures require indirect waste connections and plan the floor drains accordingly.
• Backflow prevention. A reduced pressure zone (RPZ) backflow preventer is typically required on the water supply to a commercial kitchen. This is a code requirement in nearly every jurisdiction and needs to be installed in an accessible location for annual testing.

If you want to keep your job costing tight on all these mechanical trades, having a system to track costs against your budget in real time is worth its weight. Our guide on construction cost tracking and budget variance covers the basics. Also check out our post on construction job costing for setting up your cost codes on projects like these.

Equipment Layout Planning and Workflow Design

The equipment layout drives everything else in a commercial kitchen build-out. The placement of every fryer, oven, prep table, and walk-in determines where your plumbing rough-in goes, where your electrical drops land, and how the exhaust hood is sized and positioned. If the layout changes after rough-in, you are looking at significant rework costs.

Here is how to handle the equipment layout process:

Get the layout locked early. The owner should be working with a kitchen design consultant or equipment dealer who produces a detailed equipment plan. This plan needs to show every piece of equipment with its exact dimensions, utility requirements (electrical, gas, water, drain), and clearance needs. Do not start rough-in without a finalized and approved equipment layout.

Verify the plan against the space. Field-verify all dimensions before you accept the kitchen designer’s layout. Check ceiling heights (hoods need minimum clearances above equipment), column locations, structural obstructions, and existing utility entry points. A plan that looks great on paper can fall apart when a column sits right where the walk-in was supposed to go.

Workflow matters. Commercial kitchens are designed around a workflow: receiving, storage, prep, cooking, plating, and service. The layout should move food in one direction through these stations without backtracking or cross-contamination. As a contractor, you are not responsible for the kitchen design, but understanding the workflow helps you anticipate the owner’s priorities and ask the right questions during preconstruction.

Key layout considerations for contractors:

• Walk-in coolers and freezers need reinforced floor slabs (or they sit on legs with a ramp), adequate clearance for door swings, and dedicated electrical circuits. If they are on an exterior wall, you may need insulated panels and a separate condensing unit.
• Three-compartment sinks are usually the largest plumbing fixtures in the kitchen and need hot water, cold water, and indirect waste connections. They are also heavy. Verify the floor can handle the weight when full.
• Dish area placement affects plumbing costs significantly. Dishwashers need hot water supply, drain connections, floor drains, and ventilation (Type II hood). Placing the dish area close to existing plumbing risers saves money on pipe runs.
• Dry storage is often overlooked. The health department requires that food storage areas have proper shelving (off the floor), adequate lighting, and be separate from chemical storage.

Equipment lead times are another factor that can wreck your schedule. Commercial kitchen equipment often has 6 to 12 week lead times, and custom fabrication items like stainless steel tables and specialty hoods can take even longer. Get the equipment order placed as early as possible and track delivery dates against your construction schedule. For help building a realistic schedule, see our guide on construction scheduling best practices.

Timeline Expectations and Project Phasing

A commercial kitchen build-out is not a project you can wing with a loose schedule. There are too many trades, too many inspections, and too many dependencies between systems. Here is a realistic timeline breakdown for a typical full-service restaurant kitchen build-out in an existing shell space:

Weeks 1 through 4: Preconstruction and Permitting

• Finalize equipment layout and kitchen design
• Complete mechanical, electrical, and plumbing engineering
• Submit for building permit and health department plan review
• Submit for separate mechanical, electrical, and plumbing permits
• Order long-lead equipment
• Develop construction schedule and subcontractor agreements

Weeks 5 through 8: Demolition and Rough-In

• Demo existing finishes and infrastructure
• Install underground plumbing (grease waste, floor drains, water supply)
• Install in-ground grease interceptor (if applicable)
• Frame walls and soffits for hood and ductwork
• Rough-in electrical conduit and panels
• Rough-in gas piping
• Install fire suppression rough-in
• Schedule and pass rough-in inspections (plumbing, electrical, mechanical)

Weeks 9 through 12: Mechanical Installation and Finishes

• Install exhaust hood and ductwork
• Install make-up air unit
• Set rooftop exhaust fan
• Install FRP panels, tile, and floor finishes
• Install ceiling grid and tiles
• Install plumbing fixtures (sinks, faucets, floor drains)
• Paint and finish work

Weeks 13 through 16: Equipment and Commissioning

• Receive and set kitchen equipment
• Make final electrical and plumbing connections to equipment
• Install fire suppression system (Ansul nozzles, piping, tank)
• Commission hood and ventilation system
• Final inspections: building, mechanical, electrical, plumbing, fire
• Health department final inspection
• Punch list and owner training

That is a 16-week timeline, and it assumes permits move smoothly and equipment arrives on time. Add buffer for jurisdictions with slow plan review, buildings with outdated infrastructure that needs upgrades, or projects where the owner is still making equipment decisions after rough-in starts.

Common schedule killers on kitchen build-outs:

• Health department plan review taking longer than expected
• Equipment arriving late or damaged
• Utility company delays on gas or electrical service upgrades
• Failed inspections due to code compliance issues
• Owner-driven changes to the equipment layout after rough-in

Track every milestone, every inspection, and every delivery date. When one trade slips, it cascades through the rest of the schedule. This is exactly the kind of project where having a real scheduling tool pays for itself. If you are still managing timelines with spreadsheets or whiteboards, now is the time to move to something built for construction. Our post on construction inspection checklists can help you stay ahead of the inspection process.

Wrapping It Up

Commercial kitchen build-outs are high-stakes, high-coordination projects. The margins can be good if you plan the work properly, but they will disappear fast if you are chasing change orders from missed scope or reworking rough-in because the equipment layout changed.

Get the health department involved early. Lock down the equipment layout before rough-in starts. Size your electrical service and grease interceptor correctly the first time. And build a schedule with enough float to absorb the inevitable surprises.

If you are a contractor looking to take on more commercial kitchen work, invest the time upfront in understanding the mechanical and code requirements that make these projects different from standard commercial build-outs. The contractors who do this well build strong relationships with restaurant owners and kitchen designers, and those relationships turn into repeat business.

Want to put this into practice? Book a demo with Projul and see the difference.

For more on running your construction business and managing complex projects, explore our guides on construction estimating and project scheduling. And if you are ready to get your project management out of spreadsheets and into a system built for contractors, give Projul a look.