Second-story additions that keep your yard.

On a small lot, the best place for new space is often on top of the house. A second story keeps your yard, your setbacks and your garden, and it can add views.

It is also the most structurally demanding kind of addition. The existing walls and foundation were designed to carry one story. A second floor adds weight, and California seismic requirements mean the engineer will look closely at shear walls, hold-downs and footings. Some homes need foundation upgrades; some need new posts and beams down to new footings.

Start with the structure

Before design goes far, the house should be evaluated by a structural engineer, along with a look at the foundation, the existing framing and the attic. That tells you whether a full second story, a partial second story or a different approach makes the most sense for the budget.

The stair and the plan

A second story needs a stair, and the stair takes space from the first floor. Placing it well is one of the most important design decisions in the project, along with plumbing routes for upstairs bathrooms and HVAC for the new level.

Living through it

Removing a roof exposes the house, so second stories are scheduled for dry weather where possible and protected carefully. Many families move out for part of the project. Ask for a realistic schedule up front so you can plan.

Height limits, daylight planes and design review vary by city, and some neighborhoods are strict about upper floors. If a second story does not pencil, a ground-level addition or a roof deck over a single-story addition may give you what you need.