The Project

The author,a window replacement maryland based professional,describes how to replace your own windows.

The first thing you need to know about replacing window units is that it is a moderately difficult task,and not for the beginning do-it-yourselfer. Conquer more basic home repairs first!

1. Examine the condition of the window frame carefully.

You are only going to be able to insert a replacement window unit if the existing frame is sound and solid. Look for wood rot and make sure that the shape is really squared off. Do this by

measuring both corner-to-corner diagonals and making sure the two figures are within a quarter-inch of each other.  

1. Measure twice,buy windows once!

Nothing is more important than an accurate measurement before purchasing replacement windows! According to This Old House, you’ll measure the inside width in three places,“jamb to jamb,in three places:across the top,middle,and bottom. Write down the smallest of the three measurements.”Then measure the height of the frame,again,three times:left jamb,center,right jamb,and write down the smallest number. Then measure the slope of the sill.

1. Remove the window sash.
2. Pry off the window jamb liners,using a flat bar. Without removing the casings,also remove wooden stops from the old window.
3. Prepare the window frame by scraping off old paint,patching holes and fissures,and then sanding until smooth. Then prime and paint the frame.
4. Remove the old sash weights. Again quoting This Old House: “Remove them from their pockets and insulate behind the window frame. Unscrew the access panel on each side jamb”and then just pull the weights out.
5. Prepare the weight pockets for insulating foam by drilling 3/8 inch holes near each end and in the middle. Then spray the insulating foam into the holes until it starts to come out. Foam also goes into the side jambs and the sash weight pockets (that you emptied in step 6). Allow it to harden.
6. Apply caulk to the opening of the exterior casings and along the windowsill.
7. Insert the replacement window from the bottom inside and then carefully tip it into the opening. Fit it into the exterior casing.
8. Fasten it loosely.
9. Shim the window and again measure for squareness. When it’s square,fasten it all the way with screws.
10. Finish your project by caulking and painting the new window!