"There's both a physical component and a sensitivity side to these projects. The family needs to take that into account," said Jackson, who noted that aging parents may be reluctant to move into their children's homes, and may worry about losing their independence.
"The transition will go over a lot better if you bring the parent into the conversation," said Jackson. "Ask them: 'What do you need?' 'What color do you want?'"
That's what McCann and her husband did when they decided to build an addition in 2008. Brokus, now 93, was part of the planning.
"We didn't want her to feel like a guest intruding on our house," said McCann. "She kept telling all her friends about how she was involved in the design process, and that the paint colors were her choice."
Brokus now proudly calls the addition, which includes a bedroom, wet bar and wheelchair-accessible doorways and bathroom, "her apartment," said McCann. Every month, she writes a rent check covering the cost of utilities — an act that adds to her sense of independence.
The arrangement has given the family more time together and greater peace of mind, and may have averted a tragedy in July when Brokus suffered a heart attack. Had she been alone, McCann said, she might not have called 911. As it was, she just had to walk a few feet for help.
The addition, which was part of a major renovation to other parts of the house, cost the McCanns $250,000. The average price for a bedroom addition can run from $100,000 to $400,000, depending on size and amenities, according to builders.
For the Merrills, who used a company called Next Door Garage Apartments to do their garage conversion, the cost was much lower.
The Indianapolis-based company remodels two-car garages into complete apartments within 10 days for $35,000. (The Merrills, who converted their garage 11 years ago, paid $25,000).
The company's owner, Susan Jennings, came up with the idea when she was managing a trust department at a bank and often worked with widows yearning to live with their adult children.
Jennings worked with a designer to come up with a dwelling attractive to both the adult children and the older parent. For privacy and independence, the apartment has a separate entrance, full kitchen and wheelchair-accessible features.
"The biggest advantage is that my husband can sit down with her every evening. Because of that constant contact, he has learned much more about his parents and their lives," said the younger Jane Merrill. "He would not have had that if she was in assisted living."
However, both Betsy McCann and Jane Merrill caution that this may not work for every family. For one thing, their mothers-in-law are self-sufficient and do not need daily medical care. In both families, they got along well before moving in together.
"If you can't stand one week or one weekend together, this won't work," said McCann. "You need to have realistic expectations about the impact on your life."
Nancy Thompson, of AARP, offered other tips for families considering building a mother-in-law suite for an aging parent:
— Decide what your expectations are well in advance and make sure everyone agrees. Involve the elderly parent in the process.
— Make sure the addition is built following universal design guidelines. Are counters, bathrooms and doorways wheelchair accessible? Is there a walk-in shower with grab bars? Opt for entry-level additions to eliminate stairs. Look for a contractor or builder with experience in universal design or aging in place.
- Discounts on travel and everyday savings.
- Subscription to AARP The Magazine.
- Free membership for your spouse or partner.