How Are Windows Replaced in a Stucco Home

The sill pan does one job: it catches any water that gets past the window and sends it toward the exterior instead of into the wall. Every teardown logged at window installation san bernardino claudio corallo chocolate shows the same thing, that leaks start at the sill and the corners, not at the glass. A window replacement in San Bernardino, CA comes down to how the new unit meets the old opening, and that splits into two methods.

Retrofit or insert installation

A retrofit fits the new window inside the existing frame. The old frame stays, so the surrounding stucco is often left undisturbed. Retrofit windows with a flush flange cover the old frame edge on the exterior and are sealed to the stucco face. Done carefully, this method does not leak. It suits a sound frame that is still square and solid, and it is common on stucco homes in Muscoy and Redlands where the original openings are in good shape.

Full frame removal

A full frame or new construction installation removes the old frame and exposes the rough opening. That means cutting back the stucco, and patching it afterward. The cost is the patch work, and the gain is a look at the framing, the barrier and the sill. Rot, failed paper and old nail holes show up at this stage. Not every stucco home needs this. It is chosen when the opening is damaged or the frame is out of square.

Flashing and the sill pan

Nailing fin windows rely on flashing that laps shingle style with the weather resistive barrier. Upper layers overlap lower layers, so water drains outward and never runs behind a edge. The sill pan is sloped or flashed to the exterior. Caulk alone does not make a window watertight, it only seals a joint that the flashing has already protected.

Shimming and foam

Shims set the window plumb, level and square. An out of square frame makes sashes bind and seals close poorly, and the fault shows first on a double hung or a casement, where the sash must meet the frame evenly. A slider will drag on its track. Around the frame, low expansion foam made for windows and doors fills the gap. High expansion foam can bow the frame, and a bowed vinyl window or fiberglass window will not seat its sash.

Weep holes and final checks

Weep holes at the bottom of the frame let water drain out, and they must not be sealed over. Stucco crews and painters cover them more often than anyone admits. Before the job closes, each sash is operated, the weeps are probed, and the exterior seal is checked for gaps. In San Bernardino County, dust and wind-driven rain test a install quickly, and an insulated glass unit with a double pane build will fog if water sits at the bottom edge. A picture window has no moving parts to warn anyone, so the sill pan and the weeps are the only protection.