The Complete Guide to Reglazing Windows

In this article, we'll discuss the proper way to reglaze a window pane. Reglazing windows provides several benefits including improved energy efficiency, a quieter home, extended lifespan of the window, and a cleaner look!  
If you're like many people with an older home, you might still be sporting single-pane wood windows and storms.  While they may not be quite as energy efficient as their insulated double-pane counterparts, not everyone has the money in their budget to replace them.  

The good news is that if you keep the drafts out by keeping your storm windows -- as well as the individual panes of glass in the sashes themselves -- in good shape they'll perform pretty well for you.  The problem is that old wood windows are a maintenance item, but most people don't take a good look at their condition until they're painting the house -- which is as good a time as any to make those needed repairs.

Not all professional painters do window glazing. There is an entire trade, “glazers” in the union, solely dedicated to this skill-set.  However, newer painters who are trained in the art, along with the majority of “old-school” painters who grew up with single pane windows, are skilled and efficient at making your old windows (closer to) new.
In this week's exterior painting tips article we'll discuss the proper way to reglaze a window pane.

Removing Old Window Glazing and Glass

Remove the entire window sash in need of repair, if possible, so you can work on it while it's laying down rather than trying to work on it in the frame. Sometimes this isn’t possible…or at least isn’t easy… so doing them vertical is acceptable also.

Replacing The Glazing Only (when the glass is good)

To remove the old glazing you'll need a heat gun to soften the cured putty.  Cover the surrounding panes and glazing with aluminum foil to keep from affecting them.  If the glazing is in need of repair but the glass itself is still intact, lay a piece of metal step flashing onto the glass to deflect the heat and keep from cracking the pane with the heat gun.
Apply heat until the putty is softened, then with a 5-in-1 tool remove the old putty.

Replacing The Glazing & The Glass

Wear gloves and eye protection when removing broken or cracked glass.  Remove the glazing as described above, and using your 5-in-1 tool carefully remove the old metal glazing points from the wood that secured the glass in place.

Use your heat gun to continue to remove any glazing that lived in between the glass and the frame.  Once all of the putty has been removed from the wood channel where the new pane will lay, apply some exterior wood primer to the bare wood areas and allow it to dry.

If you're replacing the glass, have the new piece cut to the exact size of the old one that you removed, or if the old one was too damaged to take a measurement, then measure the channel when the the new one will go and have the new piece of glass cut to 1/8" smaller than your measurement in each direction.

How to Reglaze a Window: Step by Step Guide

Step 1: Apply Glazing Compound

(If you're only replacing the glazing and not the glass you can skip to Step 5)  Knead a ball of new oil-based glazing compound in your hands until it's softened then roll it between your hands to make a rope.  Lay the rope of compound along the channel where the glass will sit and press it firmly into the channel.  Make sure you use plenty of compound and don't worry if you're afraid it will make a mess, you can clean it up later.  It's more important to make sure you have plenty of putty in the channel.

Step 2:  Insert the new glass pane

Using gloved hands for protection, press the new window pane into the putty and into place, gently wiggling it back and forth as you press so it can seat itself until the glass is nearly touching the wood in the channel -- about an 1/8" from making contact with the wood.

Be sure there are no bare spots between the glass and the wood channel. If there are, pull the pane back out and add more glazing compound.

Step 3:  Insert glazing points

Once the glass has been bed into the compound, lay a metal glazing point flat onto the surface of the glass and, using a stiff putty knife or 5-in-1 tool, carefully push the point into the wood frame centered along one of the edges -- gently rocking it back and forth until it is buried into the wood.  

Repeat the process on the opposite end of the pane, then again on each of the other two sides.  For larger panes of glass, the glazing points should be installed evenly-spaced every 4-6 inches around the perimeter of the glass to hold it firmly into place.

Step 4: Flip & Clean

Flip the sash over and scrape away the excess compound that pushed out while inserting the glass.

Step 5:  Glaze the other side of the window

Knead another ball of putty into a rope about 3/4" thick and press it into the gap where the glass meets the wood channel, all along the perimeter.  

To smooth out the compound, take your putty knife at about a 45 degree angle between the glass and the outer face of the wood surrounding the glass.  While applying downward pressure, pull the putty knife along the length of the compound starting at one corner and working your way to the next, removing all of the excess.  

Try to keep a crisp line in each of the four corners.  Keep your putty knife clean with each pass to avoid dragging the compound or pulling it out of the joint.

Allow the putty to dry for about 1 week until it's stiff.  

Step 6:  Prep and prime

Wipe off any oily residue from the surface of the glass with a dry cotton rag, then apply an oil-based exterior primer to the putty overlapping it just slightly onto the glass to seal down the edge. Using blue or green painters tape will create good looking tight lines.

Step 7:  Finish Paint

Once the primer has dried for 24 hours, you're ready to topcoat it with a good 100% acrylic latex paint. Top quality products like Sherwin-Williams Emerald Trim Urethane will make you really happy with your finish, and the longevity you get from your completed project.

Step 8:  Final Clean-Up and Finish

After the paint has dried you can come back with a razor blade to scrape off any excess paint/primer from the glass. Once your done here, you should have a well sealed, great looking, glazed and painted window.

 Common Mistakes to Avoid When Reglazing Windows 

• Don’t break the glass. This is not an endeavor for the impatient. Take your time, work slowly and patiently, and don’t force things.  Avoid the temptation to use a manner when inserting the glazing points.  
  
  
• If you have broken glass, remove a pane and go to your local glass supply shop and have the amount of panes you know you need (plus a few extras) cut prior to starting the job.  
  
  
• Work with warm glaze. Don’t keep the can you’re about to use in a cold garage and attempt to do this in winter.  Warm (75^o+) glazing is much easier to work with.
  
  
• As stated above, use exterior grade oil-based primer. Don’t shortcut and use latex, this is a job for oil.
  
  
• Wear glasses and gloves. Broken glass shards going into your eye is something you’ll truly regret.
  
  
• If you’re performing this task with the windows in place, use a ladder stabilizer (or better yet an aerial lift and work from a platform) that will safely bridge both sides of the window, or use two ladders and a pick. Doing this project while trying to lean across a window from the side will not go well for you.
  
  
• Be thorough. Check for air pockets. Make sure you have a good consistent base of glazing on both sides of the pane.  This will look better, last longer, dampen wind and other sounds better, and ensure top quality energy efficiency.  
  
  
• When smoothing the new putty with a putty knife, dip the blade in linseed oil (or any vegetable oil, like cooking oil) to lubricate it. This will make the application much easier, but you need to clean any remaining oil from the surface with xylene (not paint thinner or any other hydrocarbon solvent) prior to priming to ensure a good bond.
  
  
• A 45° angle is easy to work and looks great from the outside. Cut the angle in half to make the exterior side glazing less visible from the inside of the house. This practice is less common, but aesthetically superior.

• Canvas Dropcloth 
  • Use a good, clean canvas drop to use as a staging area for work. You can lay the window sash on this as a work surface, and keep all your tools in one place so things don’t get scattered around the ground.
    
    
• Metal Glazing Points
• 5-in-1 Tool
• Razor blade knife
• Razor blade scraper
• Painter’s Tape (blue or green is best)
• Oil-based wood primer
• Good quality window glazing compound (Dap 33 is the most readily available and easy to use, but for top performance track down Sarco DualGlaze or Austin’s Glazier’s Putty). 

Why Learning How to Reglaze Windows is Worth the Time 

Reglazing old or damaged wood windows isn't just about improving curb appeal—it’s a crucial step in maintaining your home’s efficiency and longevity. A well-reglazed window enhances insulation, reducing drafts, keeps out insects, and can greatly help with lowering energy costs. While the process requires patience and attention to detail, the long-term benefits far outweigh the effort. 

Confidently Reglaze Your Windows By Following These Steps

Reglazing damaged old wood windows is well worth the time and effort.  Make it a practice to walk around the house and inspect your window panes to see if they're in need of attention before you start any exterior painting project. 

If you’re hiring a professional painter, make sure you speak with them about glazing the windows. Your paint job DOES NOT INCLUDE window glazing unless it is specifically discussed, quoted and agreed to in advance of getting your quote. 99% of paint-jobs are done without reglazing, even when it’s needed. Talk to your painter and (if it’s needed) have this important process added to your job quote, it’s worth the time and expense.

If you're located in the Greater Pittsburgh or Western Pennsylvania areas and would like some assistance with your exterior painting project please give us a call at 724-898-2446, visit our 'Contact Us' page, or click on the button below to have us contact you.