What is a Window Reveal (Neg)?
A window reveal is the visible surface between the exterior face of a facade and the window or door frame. It is the “set-back” side of the wall opening — the narrow strip of wall you see when looking at a window from the side.
Why Does a Window Reveal Exist?
Window frames are not always placed flush with the outer facade. They sit slightly recessed (for protection against rain and wind). This recessed position automatically creates a reveal on both sides of the opening.
- Outer reveal — the visible masonry area on the outside, between the facade and the frame
- Inner reveal — the visible masonry area on the inside, between the frame and the interior finish
Reveal Depth
The reveal depth is the depth of this surface — how far the frame sits behind the facade. Standard in new builds:
- Cavity wall with frame in the cavity: reveal ± 15 – 30 mm
- Solid masonry wall: reveal ± 50 – 100 mm
Sealing the Reveal
The junction between the reveal and the frame is a critical point for airtightness and weathertightness:
- Polystyrene or PU foam — thermal break, filling of gaps
- Sealant (EPDM or acrylic) — sealing along the frame edge
- Reveal board or reveal profile — decorative strip for a neat transition
Reveal Block
A reveal block is a specific masonry unit with an L-shaped profile, built into the corner of the wall opening. The reveal block eliminates the laborious cutting of ordinary bricks and gives a neater junction with the frame.
Common Mistakes
- Reveal not properly sealed — cold bridge and leakage
- Frame set too far forward — rain drives directly against the window frame
- Unequal reveal left and right — window is not plumb in the opening
Related Terms
- Window frame
- Window reveal
- Door sill
- Cavity wall
- Facade
- Building regulations
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