How to Make Sure my Windows Are Installed Correctly 

Windows must be installed correctly. Poor window installation leads to many issues and inexperienced or poorly trained installers can cause air leaks and poor operation of windows. Let’s look at some possible outcomes of incorrectly installed windows.

Most window installations will go well; however, it’s a good idea to check that windows are installed correctly, even as the installations occur.

In almost every instance, new windows are a positive upgrade, so we’ve compiled a list of things you should check. If you suspect there were mistakes, contact the contractor to ensure the problems are fixed at no extra charge.  

Here is a quick list of points to check:


The opening’s measurements must be checked and double-checked.

The contractor must make careful measurements. Replacement windows are not as big as the original ones to allow proper positioning and fit. Approximately 1 inch on all sides allows for the right amount of foam sealant, a crucial aspect of air-tight replacement windows.  

Windows must be square, level, and plumb. 

Before the interior trim is installed, check that the space between the outside edge of the windows and the frame’s edge is relatively equal all around. Wood shims ensure the replacement windows are set solidly in the opening.  

New windows shouldn’t creak.

When cranking open your new window, a squeaking or a popping sound means it’s been installed improperly. The opening is too small for the window, or the window has been installed in a slightly twisted way.  

Window operation should be smooth.

If your window doesn’t open easily, the sash is misaligned, too big, and squeezed into the opening.    

Forest City Window & Door Ltd cares that your windows are installed correctly. We are window replacement contractors in London, Ontario, with years of quality window installations and happy clients since 1993.


Are there signs of water damage?

You may not see the water damage right away. Dampness beneath the window means the flashing is not installed correctly. Flashing ensures proper drainage.  

You shouldn’t feel any drafts.

If you feel a draft near your window, the foam sealant likely didn’t fill all the gaps. It is best to remove the interior trim and find the source of the air leak around the window. It is easy to add more foam.   

Is there fogging or condensation between double glass panes?

This means the seal between the two panes of glass is damaged and broken. The inert gas present between double panes of glass escapes and is replaced with water vapour, resulting in the effect of fogging or condensation.   

Caulking applied in a professional manner.

Caulk is an essential finish for window and door installations. There should be a clear line of caulk around every window. It should never look patchy, messy, or uneven. Caulking takes a couple of weeks to cure fully. Ensure your children do not see it as something to touch.  

You should receive a manufacturer’s warranty.

The window manufacturer provides warranties and specific installation guidelines are valid when followed. If you did not receive one, it indicates the contractor did not meet the requirements to pass along a warranty.  

Forest City Window & Door Ltd makes your window purchase simple with renowned manufacturers throughout North America; exceptional products snd are backed with excellent warranties. Save you money