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.

2022 Remodeling Cost Guide, download

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.


Whether you are ready to start your project or only beginning to explore your options we look forward to the opportunity to begin the imagination process with you. Click here to schedule an initial phone call  and someone from our office will give you a call at a time that works best for you.