What should you expect to pay for an ADU in Napa

Good morning, neighbors!

It's Rick from Rick Robben Construction — 707-332-7575.

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Once a week, I'll be posting a newsletter from my business page called:

"What Should You Expect to Pay?"

This week, we're talking about ADUs — also known as granny units.

Before you start, my first recommendation is simple: hire a licensed contractor.

Check the contractor's license and make sure they carry liability insurance and workers' compensation insurance. I also recommend calling your local building department and asking about the contractor. If they've never heard of the contractor, that's something I would take seriously.

If you hire an unlicensed contractor and someone gets hurt, you could be held responsible.

There are three common types of ADUs:

1. Detached ADU
A stand-alone unit separate from the main house. California law can allow detached ADUs up to 1,200 square feet, depending on the property and applicable rules.

2. Attached ADU
An ADU connected to the main house — for example, a converted garage or an addition to the home. The allowable size depends on the property and current local and state regulations.

3. Junior ADU (JADU)
A smaller unit created within the existing primary residence, generally limited to 500 square feet.

Today, let's talk about the attached ADU.

This is one of the most popular ADUs we build. At Rick Robben Construction, about 80% of the ADUs we build are attached.

Step one: Pick your contractor.

Your contractor can coordinate the architect, plans and permitting. We have an architect we work with, which makes the process much easier for our customers.

We come out, meet with you and discuss the layout. Once we know what you want, the architect prepares the plans and they are submitted to the City of Napa for review.

While the plans are being prepared and reviewed, we can also take you to the showroom to meet with our designer and select your:

• Flooring
• Cabinets
• Vanity
• Countertops
• Tile
• Sinks
• Faucets

Once the plans are approved, it's time to start construction.

THE CONSTRUCTION PROCESS

Our demolition crew comes in and strips the garage down to the studs.

The plumber then determines where the waste lines need to go. Our crew sawcuts the concrete slab and excavates the trench to connect to the sewer system.

After the plumbing work is completed, we have our first inspection.

Once the sewer work passes inspection, we backfill the trench and repair the concrete slab.

The floor is then waterproofed as required.

Next comes framing, and the existing garage door opening is converted into part of the new living space.

After framing, the plumber returns to install the water lines.

The electrician completes the rough electrical work and addresses the electrical panel requirements.

Then the HVAC contractor roughs in the heating and air-conditioning system, typically using a mini-split system.

After the rough plumbing, electrical and HVAC work is complete, we have our rough inspection.

Then comes:

Insulation → inspection → drywall → inspection

Next, we move into the bathroom.

We build the shower pan, waterproof the shower and bathroom areas, and prepare everything for tile.

Another inspection.

Then it's time for tape and texture.

After that, we install:

• Bathroom floor tile
• Shower pan tile
• Shower wall tile
• Kitchen cabinets
• Bathroom vanity
• Quartz countertops
• Sinks and faucets

The flooring goes in next.

For rental properties, we often recommend a water-resistant or waterproof flooring product that is durable and easy to maintain.

Then we install the baseboards.

The plumber returns for the final fixtures. The electrician finishes his trim-out, and the HVAC contractor completes his work.

The painter protects all of the finished surfaces and paints the entire unit.

Finally, we have the final inspection.

And then you have a brand-new ADU ready to rent.

HOW MUCH DOES IT COST?

A project like this can cost approximately $120,000, depending on the size, existing conditions, permits, utility work and the finishes you choose.

So, is it worth it?

In many cases, yes.

If the ADU rents for approximately $2,000 per month, that's about $24,000 in gross annual rent.

On a $120,000 construction cost, that represents a 20% gross rental yield before expenses, financing, taxes, insurance, maintenance and vacancies.

And you're not only creating rental income — you're also potentially increasing the value and usefulness of your property.

That's why I believe an ADU can be a very good investment when the numbers work for your particular property.

If you'd like me to discuss your ADU project with you, give me a call.

Rick Robben Construction
707-332-7575

Next week: "What Should You Expect to Pay?" — we'll talk about another remodeling project.