Nobody plans to need a walker. Then somebody has a knee replacement, a fall, or a cast, and suddenly the 28-inch bathroom door is the most important measurement in the house.

Universal design costs a little now or a lot later. There’s no third option.

This page is a working spec sheet. Print it, hand it to your designer, and check every line before you sign off on a plan.

Why this matters (and why nobody will do it for you)

According to AARP’s 2024 Home and Community Preferences survey, 75% of adults 50 and older want to stay in their current homes as they age, and 73% want to stay in their communities. 72% foresee needing grab bars.

Here’s the catch: the Florida Building Code doesn’t require universal design features in single-family homes. That includes most ADUs and additions. Your plans can pass every inspection with narrow doors and a step at every entry. If you want a space that works for a parent today, or for you in twenty years, you have to put it in the plans yourself.

The spec sheet

“Cost now vs. retrofit” compares adding the feature during design and construction against tearing into finished work later. Low, moderate, and high are relative, not prices.

Area	Feature	Spec	Why it matters	Cost now vs. retrofit
Entry	Zero-step entry	At least one entrance with no step or threshold lip	Wheelchairs, walkers, strollers, and moving day all roll right in	Now: low to moderate. Retrofit: high (ramps, regrading, door changes)
Entry	Covered landing	Room to stand, turn, and unlock out of the rain	Fumbling with keys on a wet step is how falls happen	Now: low. Retrofit: moderate
Doors	Wide doors	36″ doors (about 32″+ clear opening)	Fits a wheelchair or walker without scraped knuckles	Now: low. Retrofit: high (framing, trim, drywall)
Doors	Lever handles	Levers on every door and faucet	Usable with arthritis, wet hands, or full arms	Now: low. Retrofit: low
Halls	Wide hallways	42″+ clear width	Room to pass, turn, and use a mobility aid	Now: low. Retrofit: high (moving walls)
Bath	Turning space	60″ turning circle	A wheelchair can turn around; a caregiver can help	Now: moderate. Retrofit: high
Bath	Curbless shower	No curb, with a bench and handheld shower	No step over a wet edge; sit while bathing	Now: moderate. Retrofit: high (floor framing, waterproofing)
Bath	Grab-bar blocking	Solid blocking in walls around the toilet, shower, and tub	Install bars anywhere, any time, without opening walls	Now: low. Retrofit: moderate to high
Bath	Comfort-height toilet	Taller, chair-height bowl	Easier to sit and stand	Now: low. Retrofit: low
Kitchen	Turning space	60″ turning circle	Room to work and turn with a walker or chair	Now: low to moderate. Retrofit: high (moving cabinets)
Electrical	Rocker switches	Large rocker-style switches throughout	Press with an elbow, a fist, or a full hand	Now: low. Retrofit: low
Electrical	Raised outlets	Outlets 18″+ above the floor	Less bending to plug in a lamp or charger	Now: low. Retrofit: moderate
Lighting	Light and contrast	Bright, even lighting; contrast at edges, counters, and floor changes	Aging eyes need more light and clearer edges	Now: low. Retrofit: moderate
Floors	Slip-resistant, level floors	Slip-resistant surfaces; no thresholds between rooms	Fewer trip and slip hazards	Now: low. Retrofit: moderate to high

How to use this spec sheet

Bring it to the first design meeting

These features shape the floor plan. A 60-inch turning circle in the bathroom changes the size of the bathroom. Wide halls change the layout. If you add them after the plan is drawn, you’re redrawing it.

Install the bones now, the accessories later

Blocking is the poster child here. You don’t need grab bars on day one, and plenty of people don’t want their new suite to look like a hospital. Wood blocking in the walls costs very little during framing and lets you add bars the day you need them.

Think about the Tampa Bay lot

A zero-step entry is easy on a slab at grade. It’s harder on a flood-zone lot where the floor has to be elevated. In that case, plan the ramp, the landing, or the lift into the site design early, not as an afterthought. Our guide to building on a flood-zone lot covers elevation.

Make it look like a home

Good universal design is invisible. A curbless shower looks like a spa. A wide hallway feels generous. Lever handles look clean. Nobody walks in and thinks “accessible.” They think “nice.”

Where this fits in your project

These specs work for a backyard ADU, an attached in-law suite, or a first-floor primary suite addition. They also help resale. A house that works for everyone sells to everyone. For the bigger picture on building for a parent, see our guide to ADUs for aging parents.

Frequently asked questions

Does Florida require universal design in an ADU?

No. The Florida Building Code doesn’t mandate universal design features like zero-step entries, 36-inch doors, or curbless showers in single-family homes, including most ADUs and additions. You have to choose them and put them in your plans.

What door width do I need for a wheelchair?

Plan on 36-inch doors, which give about 32 inches or more of clear opening. That’s enough room for most wheelchairs and walkers to pass through without scraping hands or the door frame.

Should I install grab bars now or later?

Install the blocking now and the bars when you need them. Solid wood blocking in the walls around the toilet, shower, and tub costs very little during framing and lets you mount grab bars anywhere later without opening walls.

How wide should hallways be for aging in place?

Aim for 42 inches or more of clear width. That gives room to use a walker or wheelchair, turn into rooms, and let a caregiver walk alongside.

Does universal design cost more?

Some features add a little cost during construction, and many add almost nothing. The real expense comes from retrofitting later, when widening doors, removing a shower curb, or adding a zero-step entry means tearing into finished work.