Replacement installation
Replacement installation
The Replacement installation domain tests your ability to install a new window or door into an existing wall opening while preserving the building's water, air, and thermal control layers. The exam emphasizes existing-condition assessment, choosing insert versus full-frame replacement, and detailing that keeps water draining out rather than into the wall.
Core rules
- Survey before you sell. Check the existing frame for rot, cracks, out-of-square, sill slope, and evidence of leaks. Inspect the existing weather barrier, flashing, and cladding. If concealed damage is present, an insert unit can trap it.
- Insert/pocket vs. full-frame. An insert replacement sets into the existing frame and stops; it is appropriate when the frame is sound and the existing drainage path can be maintained. A full-frame replacement removes the old frame to the rough opening and allows a new mounting flange, sill pan, and flashing to be integrated with the WRB.
- Keep drainage. Do not seal weep holes or the sill drainage path. Use a sloped sill or sill pan with a back dam; seal the interior air barrier and the exterior perimeter, but leave a path for water to reach the exterior.
- Anchor to structure. Fasten through the jamb/frame into structural framing, not just sheathing or trim. Shim at sill, head, and lock/hinge points; use corrosion-resistant fasteners and follow the manufacturer's spacing.
- Flash and seal correctly. Integrate flashing tape with the existing WRB; use sealants and flashing materials that meet AAMA 800 and AAMA 711 where specified. Use backer rod and low-expansion foam; avoid high-expansion foam that can bow the frame.
- Check code and safety. Verify egress, tempered glass, fall protection, and lead-safe practices for pre-1978 housing.
Worked example
A sound 40-year-old wood double-hung sits in brick veneer. The frame is solid, the sill slopes out, and no flange is visible. An insert replacement is chosen because cutting brick for a full-frame unit would require new flashing and cladding ties. The installer still removes the sash, inspects the sill for rot, installs a sloped sill pan/back dam, sets the unit level and square, fastens through the jamb into framing, insulates with low-expansion foam, seals the interior, and leaves the exterior weep path open. If the sill were rotted or the existing WRB failed, full-frame would be the correct choice.
Traps
Sealing every gap and blocking weep holes; fastening only to sheathing; using expanding foam in the perimeter; assuming the existing frame is sound without probing; forgetting egress/tempered glass; measuring only width and height without checking square and sill slope.