Why additions are drafted differently than new homes
An addition or remodel has to work with an existing structure—existing foundation, existing framing, existing utility runs. That means the plan set usually needs to show both what's there now and what's changing, so your building department and contractor can see exactly how the new work ties into the old.
Common addition and remodel projects
- Room additions (bedrooms, bathrooms, family rooms)
- Second-story additions
- Garage additions or conversions
- Accessory dwelling units (ADUs) and guest houses
- Full or partial interior remodels/renovations
- Patios, sheds, and gazebos
See ADU & Guest House Plans and Remodel vs. Addition: What's the Difference? for more on specific project types.
Pricing works the same way as new construction
Additions are priced the same way as new homes: per square foot of the new living space (plus covered area, for the two higher tiers), with the same three package tiers—Design, Full Architectural, and Architectural + Engineered. Most additions that touch the structural system, like second-story additions or removing load-bearing walls, will need an engineered plan set.
Permitting for additions
Additions and remodels almost always require a permit, since they change the structure or systems of an existing home. Depending on scope, your jurisdiction may also require updated site plan information showing the addition's placement relative to setbacks and lot lines. See Permits & Engineering for the full picture.