Ground-level and second-story additions
A ground-level addition extends the footprint, using yard space. A second-story addition builds up and preserves the yard, but it asks more of the existing structure. Lower walls and foundations may need reinforcement, and stairs have to be placed somewhere. Which approach works depends on your lot, your budget and your city's rules.
What an addition involves
- Design that matches the house in roof pitch, windows, siding and proportions
- Structural engineering and foundation design
- Selective demolition at the connection points
- Foundation, framing, roofing, windows and exterior finishes
- Electrical, plumbing, heating and cooling extended or added
- Insulation, drywall, painting, flooring and trim
- Permits, inspections and final approval
The hard part is the join
The new room is the easy part. The connection between old and new is where problems show up: roof tie-ins that leak, floor levels that do not match, or a stucco seam that looks like a scar. Matching existing materials and detailing the joints carefully are central to a successful addition.
Rules that limit what you can build
- Setbacks: required distance from property lines
- Lot coverage and floor-area limits: how much of the lot and how many square feet can be built
- Height limits and, in some areas, design review
- Hillside rules in the foothills
- Historic district review in some neighborhoods
Building a bigger house also means checking whether existing systems can handle it. Electrical panels, water heaters and heating and cooling may need upgrades.
Other options to compare
An addition is not always the cheapest way to gain space. Converting a garage, finishing an attic or reconfiguring an existing floor plan may achieve the same goal. A good contractor will lay out those options with you, even when they result in a smaller project.