They’ve been called many things… Granny Flats, in- law apartments, guest cottages but whatever you call them, the accessory dwelling unit has been gaining popularity in recent years. Often used to allow aging parents or in-laws to live independently while in close proximity to help if and when needed, the ADU is now a major strategy to help alleviate the high demand for housing stock. Recently, there has been legislation in many states to make these units easier to build. In Los Angeles, the city actually offers free pre-approved ADU designs to speed up the permitting process. Other places have put similar strategies in place. Many municipalities have restrictions on the size of these units. The restrictions usually deal with property setbacks and the proposed ADU can usually only be up to a certain percentage of the main house on the property. Check with your municipality for specific requirements. When considering an ADU there are several items to consider.
Accessibility
Many ADUs are intended for aging parents. It’s almost always a good idea to set these units up to be accessible for the wheelchair bound. This includes setting the unit at or as close to ground level as possible. Also consider the grading up to entrances. Doors in these units should be 36” wide, if possible, for comfortable wheelchair access. When laying out bathrooms, consider wheelchair maneuverability as well. Wall mounted sinks without storage underneath and grab bars may also be something to consider.
Adaptability
Often, the ADU intended for a parent is not intended for long term use. Sometimes considering the unit’s use after it has served its purpose is worthwhile. Will you rent it out? Can it be made into a part of the existing home?
Affordability
I have designed many of these ADUs in the past. Most of them were attached to the house but some were detached (dADU). Detached ADUs tend to be more expensive as they often require separate utility lines (power, water, sewer, etc.) and require more structure, siding and roofing as well as a separate heating source. Your insurance requirements will likely change, and your property taxes will go up as well.
Considering all the potential issues and challenges now will ensure that your ADU will work well for you and your family now and in the future.