Window Installation

Replacement units versus new openings

Window jobs come in a few kinds. An insert replacement sets a new unit inside the old frame, which keeps the interior trim and causes less disruption, but gives up some glass and relies on the old frame being sound. A full-frame replacement takes the old window out to the rough opening, so we can check the framing, flash the opening properly and set a new unit at full size.

Then there is the new opening: a window where there was none, a bigger window where a small one was, or a group of windows in place of a single unit. That is framing work, and it changes both the inside and the outside of the wall.

We look at each window before recommending an approach. On older houses with rotted sills or out-of-square frames, an insert tends to trap the problem behind new vinyl. On a newer house with sound frames, an insert can be the sensible call, and we will say so.

On houses built before about 1940, original wood windows sometimes deserve a look before anyone replaces them. Old sashes can often be repaired, and some owners keep them on the front of the house and replace the rest. We will tell you honestly which ones are worth saving.

Headers, bays and cutting a bigger hole in the wall

A wider window needs a wider header, sized for whatever the wall carries above it: a floor, a roof, sometimes a point load from a beam. Before cutting, we work out what the wall is doing, and if it carries a load we will tell you before anyone swings a hammer. Temporary support goes in, the opening is cut, and the new header is set to the state building code, 780 CMR.

Bay and bow windows project out from the wall and need support of their own, from brackets or cables, plus a roof or a properly flashed head above them. A bay that sags over time usually was never supported well, so swapping one is often more involved than it looks. We check the existing support and replace it when the new unit goes in.

Structural work like this falls under the Massachusetts Construction Supervisor License, and Steve holds an unrestricted one. Resized openings commonly need a building permit, which we pull and see through inspection.

Adding a window where there was none is also a decision about the room inside. We check where furniture, outlets and heating units sit, and where the new window falls relative to floor and ceiling, before anyone marks the wall for cutting.

You hear when the order is confirmed and when it is due, and if it slips, you hear that when we do.

Flashing a window so the wall stays dry

A new window that leaks almost always leaks at the installation, not through the unit. Water gets in at the bottom corners of the opening, runs behind the trim and rots the sill and sheathing below. Much of the rot we find around older windows started exactly that way.

Our sequence is a sloped sill pan at the bottom of the rough opening, the window set and fastened to the manufacturer's instructions, side flashing over the flanges, and head flashing tucked under the housewrap above so water is carried out over the trim. Low-expansion foam fills the gap between frame and framing for air sealing, which counts for more in towns using the stretch energy code.

On a replacement in a sided wall, we cut back enough siding to do this properly, then patch it back. It takes longer than caulking a new window into an old hole, and it is the difference between a window that stays dry for decades and one that starts rotting the wall in a few winters.

Coastal and exposed houses get extra care at the head and sill. Wind-driven rain off the water finds any gap, so on the weather side we look hard at how the head flashing and the sill pan shed water.

Interior trim, plaster and finishing the inside

Full-frame replacements and new openings disturb the inside of the wall. In houses with plaster walls, cutting an opening cracks the plaster around it unless the cuts are made carefully, and we plan for patching. Extension jambs bring the frame out to the finished wall surface, and casings and stools are matched to the rest of the room or replaced as a set.

Plaster patches are blended into the old wall with the right base and finish coats rather than skimmed over with joint compound, so they do not crack along the edge a year later. Where walls are drywall, patches are taped, finished and primed to the same standard.

Stools and aprons are where good trim work shows. We cope or miter the returns cleanly, set stool height so it lines up across the room, and fill and prime so the painter has nothing to fix. Where a window moves or grows, the wall around it is repaired and ready for paint, with switches and outlets moved by a licensed electrician if the new opening lands on them.

If the house was built before 1978, old window trim and sashes are among the most likely places to find lead paint. We remove them with lead-safe practices: plastic down, no dry sanding, careful daily cleanup.

Planning the install around the weather and your rooms

Windows often have lead times of several weeks, so we measure carefully and order early. You hear when the order is confirmed and when it is due, and if it slips, you hear that when we do.

On install days we work room by room, cover floors and furniture near the work, and close every opening the same day, so nobody sleeps next to plywood. Flashing tapes and sealants need dry conditions, and we schedule around rain and deep cold rather than forcing them.

Old windows that come out leave with the rest of the debris. If someone in the house works from home, we plan which rooms are worked on which day so there is always a quiet room to use.

When the last window is in, we walk every one with you to check operation, locks, screens and trim against the written scope.

See the rest of our exterior work, or browse the gallery for rooms we have finished.