Published September 18, 2025
The most expensive addition mistake happens before a line is drawn: choosing a footprint the site or the septic system will not allow. Here is the pre-design checklist we run.
Check the dirt first
- Septic location and capacity — often the real limit on bedrooms and baths.
- Well location and setbacks.
- Slope and drainage; a walk-out foundation can be cheaper than fill.
- Tree cover and root protection zones.
- Access for a concrete truck and a crane.
Zoning, before drawings
Setbacks, lot coverage and height restrictions decide what is buildable. In several Litchfield County towns a modest addition needs both zoning approval and inland wetlands review. Bringing those conversations forward prevents a beautiful plan that cannot be permitted.
Roof tie-ins and the invisible cost
The line where a new roof meets an old one is where additions get complicated. Matching pitch, flashing and shingle, and keeping the interior ceiling height sane, usually costs more than the framing itself. We model the tie-in in the first set of drawings.
Plan the interior millwork early
An addition is the moment to solve storage, mudroom and pantry problems permanently. Deciding where built-ins go while walls are open costs almost nothing; adding them two years later costs five figures.
The short version
- Septic and zoning are the real constraints — check them first.
- The roof tie-in is the hidden budget line.
- Design millwork while the walls are open.