Cold Entryway Front Door Replacement — Insulated Unit and Sill Pan

A cold entry has three sources, and an old door has all three. The slab: an old wood door, or a steel door with a thin or broken-down core, conducts cold straight through, which is why it is cold to the touch from inside. The frame: the gap between the jamb and the framing was stuffed with fiberglass or left empty when the house was built, and the casing hides it, so cold air moves around the door no matter how the door itself seals. The threshold: a worn or fixed threshold with a gap under the door, and no sill pan under it, lets air in and lets frost form on the inside edge on the coldest mornings. Weatherstrip and a sweep touch one of those three for a while. A new prehung unit replaces all of them.

The new door is chosen for the cold. An insulated fiberglass or steel slab with a foam core and a thermal break at the edges, from options such as Therma-Tru, ProVia, Masonite or JELD-WEN. Glass kept to a half lite or less on a door that faces north or west, with low-E insulated glass and a warm-edge spacer so the inside of the glass does not frost. Compression weatherstrip around the frame, an adjustable threshold that meets the door bottom, and a storm door as a second layer if the entry has no overhang. On a door that opens straight into the living room, a solid or small-lite door and a sidelite for light is the warmest layout.

The install is what makes the entry warm. The old door and frame come out, the sill is checked, and a sill pan goes under the new threshold. Flashing tape laps to the housewrap. The frame is set plumb and square so the weatherstrip compresses evenly on all four sides, and the gap between the jamb and the framing is filled with low-expansion foam, not stuffed, the whole depth of the wall. Sealant outside, casing inside. The first cold night after the install is when you feel it: the floor by the door stops being the cold spot. Painting is quoted as a separate line — or leave it primed and caulked and paint it yourself.