What Happens During Retrofit and Full Frame Window Replacement

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Stand at the opening with a tape and a level before anything gets ordered, because every window installation in Carlsbad, CA starts with what the frame is hiding, and the work described at window installation carlsbad earth liberation front follows that order from the rough opening outward. The first decision is retrofit or full frame, and neither one wins every time.

Retrofit or full frame

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A retrofit, also called an insert install, leaves the existing frame in place and fits a new unit inside it. A full frame install removes everything down to the rough opening. Because the new frame sits inside the old one, a retrofit usually reduces the visible glass area slightly. Full frame costs more labor, and retrofit is not always the better choice, since a sound old frame can carry a new unit well.

What the opening shows

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Pulling the old window out of a full frame job exposes the framing and sheathing. That is where rot and water damage get found and repaired. Near Agua Hedionda Lagoon and Batiquitos Lagoon, the damp air and the marine layer keep sills wet longer, so soft wood at the bottom corners is common. Retrofit work hides that, so probe the old sill with a screwdriver before committing.

Flashing and the sill pan

Flashing is lapped like shingles. Lower pieces go on first, and upper pieces overlap them so water drains outward. A sill pan, or sloped sill flashing, collects whatever gets past the frame and sends it to the outside. Exterior sealant is a secondary defense. Properly lapped flashing is what keeps water out of the wall, and caulk alone will not do that job.

Setting the unit

Shims go at the corners and at the hinge and lock points. They hold the unit plumb, level and square. Check square by comparing the two diagonal measurements, which should match. An opening that looks square still needs shims, because the eye misses a quarter inch over the height of a double hung or a casement. A vinyl window flexes more than a fiberglass window, so over-tightening screws shows up fast as a sash that drags.

Filling the gap

The gap between frame and opening gets low expansion foam or similar insulation. High expansion foam can bow a frame and bind the sash, and a bowed slider or awning unit will never seal right. Fill lightly, let it cure, then trim. Interior trim and exterior sealant go on last, after the insulated glass unit has been checked for smooth operation and even reveals all the way around.