Why Style Matters for Code
The code measures the clear opening — the actual hole you climb through with the window fully open. Different window styles open differently, so the same size window can pass or fail depending on the style. This is the single most misunderstood part of egress windows.
Casement: The Egress Favorite
A casement window is hinged on the side and cranks fully open — the entire window becomes the opening. That means a smaller, cheaper casement can meet the 5.7 square foot and 20-by-24 minimums where a bigger slider would fail. Casements are the most common egress choice for exactly this reason: maximum opening from minimum wall cut. The tradeoff is the crank hardware, which needs occasional attention, and the sash swings out into the well — so the well must be deep enough to clear it.
Slider: Simple, But Half the Window Is Fixed
A sliding window opens by sliding one sash past the other — only half the window is ever open. To get 20 inches of clear width from a slider, the window must be roughly twice as wide as the opening you need, which means a bigger wall cut and a bigger well. Sliders have fewer moving parts and nothing swings into the well, which some homeowners prefer. They just need more window to do the same job.
Double-Hung: Usually the Wrong Tool
Double-hung windows open by sliding the bottom sash up — again, about half the window. Worse, the meeting rail sits right in the middle of the opening at about waist height for a climbing adult. Double-hungs can meet egress code in very large sizes, but they are rarely the smart pick for a basement cut.
What We Recommend
For most Fairfax County basements: a casement egress window. Smallest cut, lowest cost, easiest code pass. If you hate cranks or the well layout fights the swing, a slider works — it just needs a wider opening. During the free visit we measure your wall and well space and recommend the style that passes code with the least cutting.
Call (301) 679-9193 or send the form for a free written estimate.