A Carpenter’s Journal

February 28, 2010

Replacement Windows

Filed under: Materials,Uncategorized — Tags: , — Fran Maloney @ 8:05 pm

The term replacement windows is somewhat of a misnomer because when you have replacement windows installed, the entire window is not replaced.  A new frame and sash are installed inside the old frame of your original window.  The interior and exterior window trim and sill are usually left undisturbed which saves money both in materials and installation time.  Essentially you are buying new sash and balances held in a rectangular frame.  Balances are the tracks and springs the sash operates in, the sash are the movable part of the window that has the glass in it.

Replacement windows are ordered according to the dimensions of your existing sash opening, that is to say the opening that the movable sash fit into without the balances.  This  can usually be measured from the inside of the top casing down to the sill  below the stool cap, and between the side casings.  The new windows will come slightly smaller than these dimensions to allow for ease of installation and for adjustments in position that may need to be made if anything is out of square.

In order to install these windows, the old sash and balances need to be removed.  First the stops are removed, these are the small moldings that butt up to the balances to hold them in.  Then, if the balances are spring-loaded, it is easy to pull the whole assembly out by inserting a pry bar behind them and popping the staples that hold these tracks to the window frame.  The sash are under some pressure from the springs so you can expect the springs to snap up if you do not hold everything tightly together as you pull it out.  If the windows are the old ones which use weighted balances, the removal is more difficult.  The ropes that tie the sash to the window weights need to be detached from the side of the sash,  the weights will drop down in the cavity behind the casing.  There will be a pulley on each side that will have to be removed with a flat head screwdriver.  There are also usually some copper or brass tracks that sit in a thin rabbet in the window frame that keep the sash in place and act as weather stripping.  The sides of the window frame will have a little access piece that  is held in place with a screw and that has been hand cut through to the cavity where the weights are.  This needs to be opened up and insulation injected into the cavity.  The entire cavity needs to be filled with insulation.  It usually requires one or two cans to fill the empty spaces on one window.  Caulking is applied to the inside of the exterior trim and the new window placed into the opening and pressed tightly against the trim and into the caulking.  Screws through the sides of the new vinyl window hold it in place.  Then insulation is added to any space around the window up to the old window frame, there is also usually an adjustable header piece above that needs to be filled with insulation.  Finally, the stops are replaced and caulking applied around the joint between stop and window.

There are many manufacturers of replacement windows.   The supplier we use is usually Harvey Industries.

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