What Egress Means
Egress is a code term for emergency escape. Any room in a basement that's used for sleeping, whether it's a bedroom, guest room, or part of an ADU conversion, must have a way for occupants to get out in an emergency that doesn't require passing through another room.
In practice, that means a window or door that meets specific size requirements set by the International Residential Code (IRC), which New Hampshire has adopted. If your basement doesn't have a compliant opening, you can't legally call it a bedroom, and a building inspector will fail the final inspection.
NH/IRC Code Minimums
These are the numbers your egress window must meet:
| Requirement | Minimum |
|---|---|
| Net clear opening area | 5.7 square feet |
| Minimum clear height | 24 inches |
| Minimum clear width | 20 inches |
| Maximum sill height from finished floor | 44 inches |
| Window well area (if below grade) | 9 square feet minimum |
| Window well ladder/steps | Required if well depth exceeds 44 inches |
These are net clear dimensions, meaning the actual opening size when the window is fully open. The window unit itself will be larger than these numbers. We size and spec every window to meet or exceed these requirements before ordering.
The 5.7 sqft net clear requirement is the one that catches most homeowners off guard. A standard 32x20 inch basement slider doesn't come close. Egress windows are significantly larger than typical basement windows, and the foundation cut has to accommodate that.
Why You Need Egress Before Adding a Basement Bedroom
The building inspector checks egress compliance at the final inspection. If the window doesn't meet code, the inspection fails and you can't get a certificate of occupancy for the room. Adding an egress window after drywall, trim, and paint are in place means tearing out finished work, cutting through the foundation, and redoing the interior. That's expensive and avoidable.
We assess egress needs during the free consultation, before any basement finishing work begins. If a window cut is needed, we do it during the rough-in phase when the walls are still open. No rework, no surprises.
Cost Range
A typical egress window installation in Manchester costs $2,500 to $5,500 per window. That price includes:
- Foundation assessment and cut location planning
- Concrete cutting (diamond blade for poured concrete, saw for block)
- Window unit (vinyl or composite, sized for egress compliance)
- Window well with gravel drainage bed
- Waterproofing and flashing around the opening
- Interior trim and finish
- Permit and inspection coordination
Costs run toward the higher end for thicker foundations (10+ inch poured walls), stone foundations in older Manchester homes, or locations where exterior excavation is complicated by grade, utilities, or landscaping.
Our Process
Site Assessment
We evaluate the foundation type, wall thickness, and exterior conditions. We check for utilities (gas, water, electrical) near the planned cut location and assess the grade for proper window well drainage.
Foundation Cut
Using diamond-blade saws for poured concrete or standard masonry saws for block, we cut the opening to the exact dimensions needed. Temporary structural support is installed if the cut spans a significant portion of the wall.
Window and Well Installation
The egress window unit is set, shimmed, and sealed. The exterior window well is installed with a gravel drainage bed that ties into the foundation drainage system. If the well depth exceeds 44 inches, we install a permanent ladder or steps per code.
Waterproofing and Finishing
We flash and seal the opening against water intrusion, then finish the interior with trim that matches your basement design. The result is a window that looks intentional, not like an afterthought.
Inspection
We coordinate with the Manchester Building Department for the required inspection. The window must pass before any finishing work covers it.
Planning a full basement conversion? See our ADU/Basement Apartment page or our In-Law Suite page for the complete scope of what's involved.