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Garage Conversions & Granny Flats

Garage conversions and granny flats are two descriptions of the same thing; accessory dwelling units or ADUs. What’s an ADU? Basically any new or converted structure on your property that is built as an independent living unit.

That could be a conversion within your main home, a converted garage, or even a brand new structure built on your property that meets certain Orange County size requirements.

Garage Conversions & Granny Flats

Garage Conversions And Granny Flats

When you’re looking into a garage conversion to build a granny flat ADU, you have two initial choices to make. One is whether to try to convert the garage “as-is” without expanding or building on top of the current structure. The other is to commit to those alterations.

A third alternative is to raze the garage and build a totally new structure, but if you’re trying to keep your costs down you may want to compare expenses on all three options.

An existing garage may not have enough square footage to turn it into an independent living unit. You may be forced to consider expanding the original structure, but if your desire is to keep the garage but add an apartment on top you’ll definitely need to set aside some money in the budget for structural reinforcement.

If you’re concerned about city permits and related issues, know that specific ADU requirements may vary by city. The State of California has certain requirements but Orange County ADU guidelines may vary depending on what city you’re building in.

You may find that ADUs typically don’t require city approval as long as you stay within the applicable code. However, you may be required to submit plans to the local authority and apply for permits.

Some sources say that a garage conversion in Orange County could cost between $70k and $120k. Planning and construction times could range between three and six months depending on how extensive the project is.

Standalone Granny Flat ADUs

If the garage conversion project you had planned isn’t feasible, or if you simply want a standalone ADU for your granny flat, having one built from the ground up is also an option.

You can add roughly three additional months for the planning and construction phase but in some cases building from the ground up may actually be more cost-effective than reinforcing a garage and then adding an ADU on top.

Some sources estimate that building from the ground up could run from $100,000 or higher depending on how elaborate the ADU is but the price tag could vary greatly depending on what city you wish to build in.

Most of the usual caveats for garage conversion ADUs apply here; you’ll want to compare costs per square foot, construction times, and other variables among your ADU options to see which is the most affordable for you.

And keep in mind that for both standalone ADUs and conversions there are certain restrictions on height, size, and the purpose of the unit; you cannot use an ADU for an Air-b-n-b operation, for example. Orange County laws dictate that an ADU can only be rented for non-transient occupancy periods, which basically means 30 days or more.

Should I Build A Granny Flat Or Do A Garage Conversion?

Here’s a place where it pays to be brutally honest. If your goal for adding a granny flat as a garage conversion or standalone ADU is to enhance your enjoyment of the home, act as a landlord, or provide a place for a family member to live, adding an ADU might be a great idea.

But if you are thinking about adding one to raise your property values, you might want to do some basic research on the return on investment for home improvement projects like this one.

Some sources report the return on investment for an ADU like a granny flat as low as two percent. That doesn’t mean that a home won’t sell for more as a result of having an ADU but don’t expect to break even or even come close.

What To Know About Granny Flats And Garage Conversions

If you plan to add a granny flat, whether through a garage conversion or not, there are some basic steps to take to ensure you hire the right contractor and get the job done properly. One of those steps is to research your contractor; check their online reputation and you should consider making it a priority to hire a contractor with specific experience in the job you want done.

Converting a garage to an ADU is NOT the same as building one from the ground up. If you need a garage conversion, stick with contractors who have plenty of experience doing them.

No matter which type of Orange County contractor you choose, it is crucial to check with the California State License Board to make sure the contractor has an active license. Don’t hire a contractor with an expired license and be sure to check to see if the contractor has had any disciplinary action taken against them.

You’ll also need to check the contractor’s insurance certificate. Some sources warn of unscrupulous contractors falsifying insurance certificates using Photoshop; you can avoid being fooled in this way by calling the contractor’s insurance agent to verify there is an active policy.

Plans Required

Typically speaking you’ll need ADU plans and those plans may need input from a structural engineer and/or an electrical engineer. ADU plans can be drafted by a qualified professional and the costs will vary depending on the size of your project and other variables. The plans you decide upon for your project must be submitted to the local permit authority.

A Word About ADU Permits

For some, it’s tempting to skip the permit process and just get the work done. While skipping the permit process might be harder to do if you need a contractor to do the work, some have the ability to build an ADU themselves or get others to do the work for them informally.

But skipping the permit process creates a situation that causes problems later when you try to sell the home. If you built an ADU without a permit, it may not be included in the appraised value of the home when it is time to sell, and that’s an issue you can easily avoid by going through the required channels.

Preparing To Get Contractor Estimates For A Granny Flat

When the time is right to start comparing estimates for your granny flat garage conversion or from-the-ground-up ADU in Orange County, you’ll want to start the process with something called a scope of work checklist, sometimes just referred to as an ADU scope list.

This is a list of all the work you need to be done from the mundane such as trash removal from the construction site to the absolutely necessary things like plumbing, sewer, and electrical installation.

You’ll need this list to be as complete as possible and give the same exact list to each contractor so you can make a real price comparison for the scope of work you need to be done. The quality of certain materials can be an important aspect of building a living unit; you should consider price points on upscale materials such as countertops and siding compared to mid-range and budget options.

You will also want to consider features for the ADU that enhance its value. Any energy-efficient features of the ADU could be a factor, and some sources report that skylights and other natural light features may also add value, and it pays not to skimp on the flooring–a more durable floor lasts longer and adds more value.

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Joe Wallace
Joe Wallace has been covering real estate, mortgage and financial topics since 1995. His work has appeared on ABC, USA Today, The Pentagon Channel, plus a variety of print and online publications. He is a 13-year veteran of the United States Air Force and a former reporter for Air Force Television News.