Planning an in-law suite - what do we get wrong?

Accessibility, while the walls are open

If a parent is moving in, design for the next ten years rather than the first one. During framing these cost almost nothing; afterwards they cost a renovation.

• A curbless shower.
• A 36-inch door into the bedroom and the bathroom.
• Plywood blocking in the walls for future grab bars, whether or not you fit them now.
• A bedroom that can take a hospital bed with room to work around it.

Sound, which nobody thinks about until week one

Share as few walls as possible. Where you must, insulate the cavity and use resilient channel on at least one side. Keep the suite bathroom off the shared wall with the main bedroom, and do not run the suite plumbing through a wall behind a headboard.

The kitchen question

A second full kitchen is frequently the line between an in-law suite and a second dwelling unit, and the second one brings zoning, utility and sometimes impact-fee consequences. Before you plan a range and a full-size sink, ask the planning desk what triggers that classification on your parcel.

A wet bar, a microwave and a full-height fridge gives most families ninety per cent of the function and none of the argument. If a genuinely separate unit is what you need, the route is an accessory dwelling unit.

Then the ordinary construction decisions

1. 1Separate HVAC zone or a dedicated system, because one thermostat for two households does not work.
2. 2Its own entrance if the lot allows, even for an attached suite.
3. 3Lighting designed for older eyes: more of it, and on motion sensors between bed and bathroom.

I build these in Seminole County, and the accessibility items are the ones I push hardest for, because they are cheap now and expensive later: aging-in-place modifications.

The conversation to have before the drawings

Two households, one roof, works when the boundaries are decided in advance: the entrance, the laundry, the parking, and whether meals are shared. Those decisions change the plan more than the square footage does.

It is also worth deciding what happens to the space afterwards. A suite that becomes a guest wing, a home office or a rental later is a different design from one that only works for one person, and the difference is usually a door and a service connection.