How to properly fix this window gap?

Question

I recently bought a condo and found this relatively large gap in the window (0.425"). This should be covered by the builders warranty but I want to make sure that the developer doesn't do a hack job in an effort to save money (like installing a piece of foam). What would be the proper way to fix this and what kind of contractor should I consult with?

Thanks!

Holden Schwabe · Answer

Hi Konstantin,

Hard to tell from the pictures but it looks like the window unit was installed out of square during the initial installation.  If it is a remodel or replacement window, its not to bad since the fasteners attaching the window are accessible from the inside jamb. They would need to remove the fasteners and possibly the interior trim, re-shim the window square and level, re-secure it with screws, and re-caulk the exterior if necessary.   If its a new construction window, the window is usually fastened on a 'nail fin' which is located behind the siding on the exterior surface of the wall sheathing.  This is a lot more work to remove because you often need to remove the siding in order to un-fasten the window. There are some tricks that can be done depending on the window type, siding type and wall construction that a good replacement window installer will know.  I would recommend calling a replacement window installer or a local handyman that has a lot of replacement window experience.   Hope this helps- Holden

Konstantin Klitenik · Answer

@Holden Schwabe Thanks, that gives me some background on the scope of the issue.  Here's a full frame photo of the window.  There is no taper at the top.  The property was a gut renovation but they kept the old windows (not sure if just the sashes or the frames as well.