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A Senior-Safe Backyard Granny Flat

How to Design In-Law Apartments for Aging Parents

Drawing representing a steel-framed granny flat.When constructing a backyard building for use as a granny flat for elderly parents, planning is paramount.  Just throwing up a small house on your property will not get the job done. 

Remember, even mature adults who are physically active today may require safety adjustments to their home in the future.  Incorporating senior-friendly features into the building now can save you from expensive remodeling later. 

Alternative Granny Flat Terms

First, acquaint yourself with the right terminology.

A backyard building used as a residence is called an “accessory dwelling unit” (ADU).

Popular alternative names for a backyard residence for aging relatives include:

  • Backyard apartment
  • Backyard guesthouse
  • Elder apartment
  • Elder cottage
  • Granny flat
  • Granny pod
  • In-law apartment
  • Mother-in-law apartment
  • Mother-in-law cottage
  • Senior apartment
  • Senior cottage

Before Designing In-Law Apartments

Before you plan anything, check with your local building permit department for zoning, restrictions, regulations, guidelines, and easements for a residential backyard building in your area.

Examine your property title for ADU constraints.  Be sure your homeowners association does not prohibit or limit ADUs on your property.

Choose an overall size for the in-law apartment, based on the senior’s needs, the space available on the property, and your building budget. 

A mother-in-law cottage averages about 800-1,000 square feet.  However, larger in-law homes of 1,200-1,500 square feet may better fit the needs of a senior couple.

In planning, also keep in mind the alternative uses for the structure in the future. 

For example, if you plan to rent the ADU as an apartment later on, you may want to increase the building space.  However, if you plan to convert the structure into a home office down the line, a smaller ADU may be better.

Overall Design Tips for a Senior’s Backyard Guesthouse

Photo of a smiling granddaughter with her arm around her grandfather's neck.Design the ADU as a single story structure, with a one level floor plan.

Keep power sources to the in-law dwelling separate from your main house.  That way if you ever decide to rent the home, you can easily keep the utilities separate.  It also allows you to cut the power when the ADU is unoccupied.

Design the granny flat exterior to be both attractive and low maintenance.

For easy maneuverability for seniors who may need walkers or wheelchairs, allow 60” of clear, unobstructed turn-around space in every room—and in front of the kitchen appliances.

Hallways should be 36” or more in width.

Include additional bracing around tubs, showers, toilets, and along hallways to support grab bars or handrails. Then you can install attractive, sturdy grab bars and handrails as needed throughout your prefab granny flat.

Senior-Safe Bathroom and Kitchen for a Mother-in-Law Cottage

The minimum width for stand-up showers should be 36” with a fold-down seat. 

Add a handheld showerhead with a 6’ hose. 

Use shower stalls with built-in antibacterial protection.

Lever-handled faucets for sinks and showers prove easier for seniors to operate.

Choose faucets with anti-scald controls. 

Add a pullout spray faucet at the kitchen sink.

Install chair-height toilets.

Choose slip-resistant flooring for both the bathroom and the shower.

More General Senior-Safe Design Tips

Focus on easy-to-clean building materials. 

Avoid fabrics and composite wood materials, which may outgas and contribute to poor indoor air quality.

Preventing Falls in a Granny Flat

Falls are one of the major causes of a sudden downward spiral of health in the elderly.  Create a home that diminishes the chances of stumbles and falls. 

Keep thresholds at the entry— and throughout the apartment— as low as possible to avoid a tripping hazard. 

Build a well-lighted covered entrance without steps to help prevent stumbling.

Wheelchair ramps must not be greater than a 1:12 slant— meaning a one-inch rise for every twelve inches in length.  Include curbs on both sides of ramps at least 2” high.

Power cords can tangle and trip someone who is a fall risk.  Incorporate numerous electrical outlets to avoid the use of too many electrical cords. 

Placing outlets every 10’-12’ helps eliminate the need for power strips or extension cords. 

Secure excess cord length to the walls.

Natural Lighting for Elder Apartments

Let there be natural light! 

As vision dims with age, exceptional lighting becomes vital to seniors.  Ample natural light not only improves sight, but often plays a critical part in mood as well. 

Exterior and interior doors should be a minimum of 36” wide.  Entry doors with sidelight panels insure privacy, while increasing natural lighting.

Plan for numerous, large windows. 

Install windows lower in the wall, to increase lighting.  Invest in well-insulated double or triple-pane windows to decrease drafts and increase energy efficiency.  Be sure window hardware is easy to operate.

Choose levered-style door hardware.  Levers are often easier for arthritic hands to operate than twisting a standard doorknob.

Ample Interior Lighting for Vision-Challenged Seniors

Include an extraordinary amount of interior lighting.  Make hallways, entry ways, closets, baths, laundry areas, and pantries exceptionally well-lit.

Install light switches by the entrance of every room and hallway— no higher than 48” from the floor. 

Lighting fixtures with multiple bulb receptacles provide greater light. 

Rocker or touch-type light switches work best for older hands.

Steel-Framed Buildings for Housing Aging Relatives

Photo of smiling senior couple before a RHINO steel-framed home.A RHINO pre-engineered steel building works perfectly as an elder apartment, backyard guesthouse, home office, man cave/she shed, workshop or any other backyard building.

Our structures offer the benefits of a commercial-strength structure for your backyard dwelling project.

In addition, RHINO steel buildings will meet or exceed all your current local building codes for the lifetime of your structure.

Our versatile structures offer significant advantages for your residential building projects, including:

Please phone RHINO Steel Building Systems today at 940.383.9566.  Our metal building specialists will answer all your questions and provide a free no-obligation quote.


(Updated 6-16-2021.  Originally published 4-15-2016.)