Once framing is complete, and covered by plywood sheathing, the house is ready for the systems that will make it ready for modern life: functional, safe, and comfortable.

This stage is called the rough-in phase because the main plumbing, electrical, HVAC, ventilation, fire sprinkler, and low-voltage systems are installed before insulation and drywall cover the walls and ceilings.

Most homeowners will never see this work again once the house is finished, but it is one of the most important stages of construction. Behind finished walls, there are many miles of water lines, drain lines, electrical wires, ductwork, vents, sprinkler pipes, and connections that all need to be carefully planned, installed, and inspected.

Rough-in stage: Plumbing, Electrical, HVAC and Fire Sprinkler Systems

During this stage, all major systems are installed according to the approved plans. The work has to be accurate because after walls and floors are closed, plumbing changes become much more difficult and expensive.

Plumbing Rough-In

The plumbing rough-in includes the water supply lines, drain lines, vent pipes, bathroom plumbing, kitchen sink connections, laundry hookups, and other plumbing points throughout the house.

The house, that we use as example in this construction process series, – was built on a slab foundation, so all plumbing locations had to be prepared early. During the rough-in phase, the remaining plumbing work is connected and prepared for future fixtures such as toilets, sinks, showers, tubs, laundry appliances, and kitchen sinks.

Electrical Rough-In

Electrical wiring is also installed throughout the framed structure during this stage. Wires are routed through the framing and brought into electrical boxes for future outlets, switches, lighting fixtures, appliances, smoke detectors, bathroom fans, kitchen equipment, laundry equipment, HVAC equipment, and other devices.

This is also the stage when future lifestyle needs should be considered. Extra outlets, dedicated appliance circuits, EV charger preparation, smart home wiring, security systems, internet access points, and outdoor electrical systems are much easier to plan before drywall is installed.

Main Electrical Panel

As part of the electrical rough-in work, we also installed the main electrical panel. The panel is the central distribution point for power throughout the home. Every circuit starts from the panel before delivering electricity to lights, outlets, appliances, HVAC equipment, kitchen systems, laundry equipment, and other electrical loads.

Safety first! Proper panel sizing, grounding, circuit protection, breaker organization, and labeling are essential for safety and long-term reliability.

For this project, the main panel was installed, grounding was completed, and electrical circuits were organized according to the approved electrical design.

Many older California homes were built with 60-amp or 100-amp electrical services. Most new homes now require 200 amps or more to support modern electrical demands.

A modern home uses far more electricity than older homes, so the electrical system must be planned not only for today’s needs, but also for possible future upgrades such as EV charging, solar, battery storage, larger appliances, or additional equipment.

HVAC and Ventilation Rough-In

The HVAC and ventilation systems are also installed during the rough-in phase. This may include ductwork, refrigerant lines, air returns, exhaust fan ducts, kitchen hood ducting, dryer venting, thermostat wiring, and other mechanical components required for heating, cooling, and ventilation.

Good HVAC planning affects comfort, indoor air quality, energy efficiency, and long-term performance. Ducts and vents need to be placed correctly so the home can receive proper airflow once the system is running.

California’s Energy Code also continues to strengthen requirements for newly constructed homes, including heat pump use, electric-readiness, and ventilation standards, so mechanical work must be coordinated carefully with current code and project requirements.

Fire Sprinkler System

The fire sprinkler system was installed during this rough-in stage as well. Sprinkler piping is placed before walls and ceilings are closed, so the system can be properly connected and positioned throughout the home. In many California jurisdictions, fire sprinkler systems are a standard part of new residential construction and are reviewed as part of the permit and inspection process.

California Code requirements include:

✓ Rough plumbing inspection
✓ Rough electrical inspection
✓ Rough mechanical / HVAC inspection
✓ Fire sprinkler rough inspection
✓ Gas line pressure test, if applicable
✓ Electrical service / main panel inspection, if applicable
✓ Rough framing / combination rough inspection
✓ Insulation inspection before drywall

Rough-in work is one of the most complicated stages in house construction. Mistakes at this stage are unacceptable, so there is a big list of inspections to ensure everything is installed reliably and safely. Depending on your city, there might be less inspections (some could be combined in one), or even more inspections than mentioned here. 

Insulation and drywall: last steps of rough-in stage

For a new residential home, insulation is commonly installed in exterior walls, attic or roof areas, ceilings, floors above unconditioned spaces, garage-adjacent walls, and sometimes interior walls for sound control. The exact material and R-value are selected based on the approved plans, energy calculations, and inspection requirements.

In California, insulation is also part of energy-code compliance. The California Energy Commission’s Building Energy Efficiency Standards include requirements under the Energy Code. Exact insulation requirements depend on the project, house location, approved energy calculations, and current code cycle.

Insulation is important because it slows heat transfer through the home’s walls, ceilings, floors, and roof areas. It performs well when installed correctly. Good insulation helps with overall comfort, humidity control, and noise reduction. According to the U.S. Department of Energy, proper insulation also reduces heating and cooling costs, keeping conditioned air inside the home, reducing heat gain during hot weather, and heat loss during colder months.

Common Types of Insulation

The type of insulation depends on the area of the house, the design of the wall or roof assembly, the required R-value, moisture conditions, fire-safety requirements, and the approved plans.

• Fiberglass batt insulation – one of the most common options for new construction. It is often installed between wall studs, ceiling joists, and floor joists. 
• Mineral wool insulation can also be installed in wall, ceiling, and floor cavities. It is often used when the project needs better sound control, improved fire resistance, or denser insulation in certain areas.
• Blown-in insulation, usually fiberglass, cellulose, or mineral wool, is commonly used in unfinished attic floors, open new wall cavities, enclosed existing walls, and hard-to-reach areas. 
• Rigid foam board insulation is often used for foundation walls, crawlspace walls, floors, ceilings, exterior continuous insulation, low-slope roofs, and below-grade foundation walls. 
• Spray foam insulation can be used in open wall cavities, enclosed walls, attic floors, and attic ceilings. It expands to fill gaps and can help reduce air leakage. Usually requires a very skilled installer. 
• Duct insulation is used when HVAC ducts pass through unconditioned spaces, such as attics, crawlspaces, or garages. 

Drywall Installation

Once insulation is installed, inspected and approved, interior walls can be covered by drywall.

Drywall panels, also called gypsum board, are measured, cut, and fastened to the wall and ceiling framing. Openings are cut for outlets, switches, vents, windows, doors, and other fixtures. After the panels are installed, the seams, corners, and screw heads are finished with joint tape and joint compound.

The finishing process usually requires several coats of joint compound, with drying and sanding between coats, until the walls and ceilings are smooth enough for primer, paint, tile, or other final finishes. 

Homeowner Tip for Rough-In Phase

Take time to think about how you will actually live in your future home before rough-in work is completed. Confirm outlet locations, lighting plans, appliance placement, bathroom fan locations, kitchen hood placement, laundry setup, internet access points, security camera wiring, outdoor outlets, EV charger preparation, and future smart home features.

Small decisions made at this stage can make the finished home much more convenient and functional.