How to Replace the Glass in a Wood Frame Window.

My home has wooden framed windows that, from time to time, have been broken.  I employed a professional glasier to replace one of my windows, which cost just under $500.  I decided to watch him work so that I could learn how he did this, in order to do the repairs myself next time.  It was surprisingly easy, and increased my confidence in being able to do it myself next time.

When the next window was broken I bought the glass myself for $120 and completed the job.

I decided to create this instructable to assist people to save money in the repair of their own windows and have a feeling of satisfaction that comes with knowing how to do something yourself.  Remember, the first time I did this I was very worried I would screw it up and get seriously injured.  It turned out to be not very difficult and each time I repaired a broken window I gained confidence.  Don't be afraid of this repair job, it is easy to do and could end up saving you a lot of money... it could even be a new career!

If you are interested in this, you may be interested in reading my blog.  It is located at Little Tassie Prepper.

Step 1:

The tools required.

A reliable Tape measure - You need to take the measurements in order to buy some new glass.
Paint scraper - This is to remove the Sash and any glue
Stanley Knife - To cut the Sash free from the frame.
Hammer - to Hammer the Sash nails back into the frame.
Thick Gloves - to protect your hands from broken glass.
Safety Glasses - to protect your eyes.  Hopefully you will not need them, but better to be safe.

First step is to use the measuring tape to ensure that you purchase the correct size glass to fit the frame.  Take extra care to make sure you measure this properly… you need to take the correct measurement or you will waste money and time.  I find that measuring from inside of the frame to opposite inside part of the frame.  I then remove one millimeter from the measurement to ensure that I can fit the glass into the frame.  Once you have copied down the measurements, contact a glass supplier and purchase the glass required.  You can take a section of the glass with you if you like, so that the glazier can see they type of glass which you used.  At the very least you should explain the use for the glass when you order it so that the merchant can assist you in recommending the thickness you would require.

Once you have the glass purchased, you need to remove the broken glass from the frame.  Use the Stanley knife to cut the paint from the window frame.  Run the knife carefully down the Sash of the window (this is the section which holds the glass into the frame).  Do this to all sections of the Sash.

Step 2:

Once the sash is separate from the frame, you take the paint scraper and insert it into the gap between the Sash and the Frame.  This is to help pry the Sash from the Frame.  I was advised by the Glassier that some houses (such as mine) have the Sash glued onto the Frame, so in these cases you use the paint scraper to unpick the glue from the inside of the crack.  Do this to all sections of the Sash, as well as the corner sections.


Use the scraper to pry the Sash from the window frame.  Try to keep the nails within the Sash if possible as it makes it easier later.  Any nails removed need to be collected and used later.  Once the Sash is removed, make sure that the glass does not hit you or fall out. 

Now remove the glass from the frame.  I try to remove it as one piece, yet I usually have to end up breaking it out.  Make this fun if you like.

Step 3:

Take the Paint Scraper and remove any debris (such as pieces of wood shavings, dirt/dust, or glue) from the window frame, you need the area to be clear of items which will stop the window from making a good seal.  Check the Sashes to make sure that they are in good order, have no additional debris on them, and hammer the point of the nails so that they can be hammered back into place.  This is basically reversing the nails so that the point is just within the wooden Sash.



You may need another person to assist you in the next section.  Have the hammer handy, as well as the removed Sashes and nails.  Carefully place the new window into the frame.  Hold it in place so that it is tight against the frame. 

Now... this is a very delicate part.  Take the top Sash and place it into place, carefully hammer the nails into place.  You need to hammer carefully so that you don't break the window.  I find that having the nails already in the wood makes it much easier to hammer them back in.  Place the Bottom Sash back into place and hammer it in.  Then do the sides.  I have been advised by professional Glaziers that you should not place glue or window putty on the window to keep it in place.  It makes it harder to remove broken glass in future breaks.  I was told that the putty is to be used if there is a bad seal on the window, to prevent any moisture from getting through.

Now step back and admire the great work you have done.