How Homeowners Benefit from ADUs and Home Additions

Over the last few years, both public opinion and local legislation regarding ADUs – short for “accessory dwelling units” – have evolved. Today, Washington State allows homeowners with sufficiently sized lots to build up to two 1,200 square foot ADUs. Other Western states like California and Oregon have passed similar laws. In 2021, California Governor Gavin Newsom signed Senate Bill 9 – which permits up to four ADUs on a single residential lot. Earlier this year, Washington State Governor Jay Inslee also eyed new legislation expanding ADU permissions to alleviate our housing crisis. East Coast states like Massachusetts and New Hampshire are finally weighing changes to their laws too. Of course, there are critics of ADUs and home additions on both coasts. Critics often argue that increased ADU construction will lead to more short-term rentals, traffic jams and parking shortages. However, ADUs offer a number of benefits to both homeowners and the neighborhoods in which they are built. From passive income to additional living space, follow below to learn all about the trend towards ADUs and home additions in Washington State.

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Is An Addition Worth the Money?

Homeowners often ask whether building an addition or detached accessory dwelling unit is worth the money. As long as the ADU or other addition is constructed carefully, lawfully and fully to code, it should add value to your property. According to Charlie Melvin with full service design-build firm Cali ADU, the average LA homeowner could recoup 88% of their investment in an ADU. Melvin notes that a 1,000 square foot detached ADU could add "an average of $470,000 to your property value." Not only do ADUs and additions increase the amount of livable square footage on your property. They also offer passive income if used as a rental unit.

However, the cost and ROI of your addition or ADU both depend heavily on your local housing market. A garage conversion might return less, because it eliminates valuable storage and covered parking space. Additions that obstruct outdoor space could also return less of your investment upon sale.


What is a Bump-Out Addition?

Building a bump-out addition is one of the most popular ways homeowners increase their primary dwelling's square footage. Lee Wallender and Lexie Pelchen explain these remodeling projects in their article "How To Plan A Bump-Out Addition To Your House" for Forbes Advisor.

According to Wallender and Pelchen, "a bump-out is a minor addition to a house." Bump-outs will increase the home's "total square footage but [will not] reach the scale of a full addition." They note that a bump-out could be "as small as two or three feet that push out the side of the house." Alternatively, a bump-out could be "as large as a single room." Minor bump-outs are especially common in updated bathrooms and kitchens of small older homes. Keep in mind however, if the foundation or roof needs to be altered to accommodate a large bump out, the cost will increase significantly.


Will An Addition Increase My Property Taxes?

Unfortunately, most major renovations that involve structural alterations or added square footage increase property taxes. This is especially true of renovations that bump up your home's livable space. Keep in mind that only certain renovations trigger property tax reassessments.

For example, detached ADUs usually trigger a partial reassessment. This means that the new unit is assessed as a separate structure. Property taxes related to the original single family home should remain unchanged.

What are the Costs?

Download our free Snohomish County Home Remodeling Cost Guide to learn more about the costs and considerations of remodeling a:

  • Kitchen 
  • Bathroom 
  • Whole home 
  • Exterior of home
  • Home addition or ADU**
**Please note: Due to the unique requirements of your home addition, production costs can vary dramatically. Rest assured our remodeling process includes engineering and design, after which, you will be provided with a fixed investment price for your custom home addition.
A Step-by-Step Guide to Remodeling Your Snohomish County Home FREE download

VanderBeken Remodel and all of their specialty trade partners were a pleasure to work with. They were clean, conscientious of our time, and even were great with our young boys.

Mr. & Mrs. L. Snohomish, Washington Master Bathroom

Ron and Jen were committed to helping us build what we wanted. They asked great questions to set us up for success and followed up to make sure they delivered to our satisfaction. Remodels always have unexpected issues, and Ron helped us think through viable options to overcome the challenges. Ron and Jen are our go-to people for remodels. We will be calling in them again. We encourage anyone who feels strongly about getting good quality and thoughtful partnership to meet them.

Mr. & Mrs. P. Snohomish, Washington Carriage House

The Vanderbeken team just completed a major interior remodel project for us and we could not be happier with the results. We were impressed with the integrity their team brought to the process from beginning to end. Very important to us was their follow up and attention to detail. Finally, the quality of the workmanship was outstanding.

Mr. & Mrs. R. Camano Island, Washington Whole House Remodel

VanderBeken Remodel met or exceeded my expectations regarding their skills, cleanliness, organization, and craftmanship. They were very professional and kept their word. It did not feel like there was a stranger in my home. They were great with my pets and respectful of my home.

Kerry Q. Marysville, Washington Kitchen Remodel

I was very pleased with the work they did. Everyone involved did an amazing job and we are very happy with our kitchen!

Mr. & Mrs. S. Edmonds, Washington Kitchen Remodel

This is the third time we have hired VanderBeken Remodel to work on our home. In every project from converting a garage into living space with woodstove installation and granite surround, to building a detached carport, to this, our latest experience, adding over 1,000 sf to our house, leveling the yard and widening our driveway, VanderBeken Remodel has excelled in everything. Ron is personable, available, and fastidious in every detail. His dedication to quality and beauty is evident in every corner of our home. For ten years we planned our “dream home” and to see it crafted out under Ron’s expertise has been an amazing experience. It’s more beautiful than we ever imagined! We always recommend VanderBeken Remodel to everyone.

Mr. & Mrs. W. Monroe, Washington