Can I Convert My Basement to an ADU?

Introduction to Accessory Dwelling Units

As a homeowner, your life changes over the years, and you may want some changes for your home as well due to your life circumstances. Maybe your children moved out, so you are now empty-nesters, or you have a parent growing old, and they are on a fixed income, or you just want to find another source of revenue. All of these are great reasons to look into an ADU.

An ADU is an accessory dwelling unit that goes by other names such as a granny flat, in-law units, backyard cottages, secondary units, etc. The ADU is an independent living area within a property aside from the main home that can be shared with family members or rented out to an independent tenant.

One of the ways to implement an ADU on your property is to convert your basement. An incentive to consider an ADU, is the current housing shortage in the state of California. Many local jurisdictions have relaxed their requirements for ADU’s in order to help promote implementation. This article will look into the basement renovation process for creating an ADU on your property.

Basement Conversion

The basement may be currently collecting dust as a storage area, but there is much potential for space if you want to renovate it. In any design process, you begin by planning out the floor plan for space. An ADU unit should incorporate a bathroom and living area that can be used as a studio. Furthermore, some layouts may incorporate a modified kitchen, separate bedroom, and a laundry room. This all depends on the affordability of your basement renovation budget and the size of the area. Some things to keep in mind for a traditional basement space being converted for a habitable space are the following:

  • Ventilation and accessibility – Since this is a basement, you will need to add windows for ventilation and upgrade any entry points for the basement. These entry points could be a stairway from the main home that should reach the basement finished floor elevation.
    • An exterior basement entry may be desired to avoid the tenant from entering the main home. However, adding this may be costly and requires a bit of exterior space on the home that may not be available.
  • Headroom Clearance – the height from the finished floor to the basement’s ceiling should be within the allowable building code height. Although this code depends on the local municipality’s requirements, you should assume a minimum of seven feet (7’).
  • Consider any exposed piping or mechanical equipment
    • Have any exposed piping insulated before drywalling the framed structure. This protects the walls and ceilings from condensation dripping off of the cold-water pipes. Also, you will prevent heat loss from the hot water pipes.
    • Ensure there is clearance from mechanical equipment in the basement to allow an adult person to maneuver within the space.
  • Provide a soundproof basement ceiling – the main home has someone living in it, more often than not, so be considerate of the future basement tenant by layering the drywall. This can be achieved by adding fiberglass batts between the joists and fastening two layers of the drywall to them. This technique helps to isolate the wall from the joists, significantly reducing vibration from the upstairs.
  • Think about the lighting – since basements are typically dark and gloomy spaces, you want to make sure the habitable space has enough lighting. Install recessed lighting cans throughout the space to avoid dark spots. Recessed lighting is installed directly inside a ceiling, wall, or other surface. Recessed fixtures consist of three main components —  housing, trim, and bulb.

The conversion of the basement may need more than a DIY facelift. Consider hiring a professional team like Design Everest to ensure the basement conversion goes smoothly and meets building codes.

Basement ADU

The basement you wish to make into an ADU may already be finished; however, there are a lot of factors concerning a basement when it comes to it being used as an ADU. There should be some fundamental factors about the space that make it livable. Here is what you should consider:

  • Kitchen accessories – the ADU should have a small refrigerator, microwave, and an area for storing pantry items at the minimum.
  • The unit should have ample storage or even built-in storage areas.
  • The bathroom should have a humidistat to allow for moisture to escape the area.
  • Make sure the sewage drain lines are installed correctly – this could mean a tank and pump needs to be installed for the basement bath.
  • Hire a plumber to install a back flow valve in case the drain lines become backed up. This is important for below-grade plumbing.
  • Think about ways to simplify the plumbing, like making sure the bathroom equipment (i.e., tub, sink, toilet) is installed adjacently along the same wall.
  • Avoid too many walls in the ADU, and if walls are needed, think about half-wall partitions or only walls between structural columns in the basement. This allows for the area to not be closed in.
  • Consider customizing the area to lead the tenant to the best use of the space. This could mean making an area for the bed by placing storage cabinets or creating a built-in workspace/dining area.
  • The basements are typically colder than the rest of the home and, therefore, will not require as much cooling but more heating. Consider a HVAC upgrade to allow additional thermostat controls and heating zones.

Basement Renovation

Your basement renovation will be one that leads you to accommodate a beloved family member or make some extra money. Make sure that any applicable permits are handled for the renovation. Although the permitting process for a finished basement can cost a few thousand dollars, it is important to have all of the permits in place and construction inspections done, so you can market the renovated basement if you were to resell the property. The permits will require what most building permits do – mechanical, plumbing, electrical, and architectural construction drawings. Also, keep in mind additional taxes or utility requirements for your area. Some places require a supplemental tax to be paid bi-annual for a property being leased out. The local water district may require an annual fee for leased spaces as well. The basement renovation is worth the investment, and you can do the finishes for the basement. Licensed professionals should handle the initial inspection of the space to ensure the building permits and all necessary work is completed correctly.

Design Everest can provide consultation and a free estimate of your home renovation today. Just call the following number: (877) 704-5687.

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