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Glaze or Caulk Windows?

We are getting ready to paint exterior windows. We have three "fixed door" windows on the front of our house. The glass is a bubble envelope (not sure the technical name); it is insulated, but instead of a true double-paned glass, it is one continuous glass wrapped back on itself with an air insulated gap. While prepping the area, I noticed a putty in between the glass pane and wood frame. I'm guessing that this is a glazing putty (after I did an internet search!).

My question is...Do I reinstall more glazing putty or put some exterior acrylic caulk (like we've been using on the rest of the house trim)?

Keep in mind that I'll be painting over this. Some of the putty that is there is black moldy looking, so I'll be trying to pull as much out as I can.

Also, what method of cleaning is typically used in preparation for glazing putty? If that is what is recommended to use.

Thanks in advance!

carrie palmer
Re: Glaze or Caulk Windows?

Exterior good quality caulk remains flexible and waterproof for an extended period. Traditional 45-degree angle is a concern when it comes to caulk. Caulk colour is also a concern, because some caulk can not be painted.
I would suggest you not to stick with caulk because they do not stick to dissimilar or porous wood surfaces very well. Caulk may even detach.
Glazing can be worked then reworked, cleaned off the glass easily, unlike the caulk which makes a mess of things.
If you prefer to go with caulking remove the old caulk and clean the area properly, then caulk all the joints between your window frame and the surrounding structure. Remember to fill wide or deep gaps using foam rope to reduce the amount of caulk used.
Glazing tends to harden with time and thus break easily forming gaps around the window frame.
A year back when I sought expert advice from a fixed windows installation toronto, they suggested using a putty knife to remove old glazing. Later replace them with fresh glazing. For neat sealing, use a glazing tool to smooth the compound evenly. The packed glazing material has a short shelf life, thus it is advisable to use compound remained from the previous year or save some for the next cold season.

Re: Glaze or Caulk Windows?

Caulk shrinks!


Re: Glaze or Caulk Windows?

To be clear on the matter. Do you have wood windows? Or some cheap junk?

If you have multiple panes in your wooden doors or wooden windows, you use glaze. You replace the gze about every 20 years when it begins to crack. Remove the old, as much as will come out, and then re-glaze the pane. Prime and then paint with a good quality oil based primer and a good quality outdoor paint. I like using marine grade oil based paints for all my exterior wood.

If you are referring to the joint where the window frame meet the rough opening of the side of the house. Then you need a high quality silicone caulk. Keep in mind, most caulking will not last but about a year or two at the very most. You will need to keep replacing it. And you cannot paint over silicone. I never recommend using latex outdoors. What is latex? Correct, a liquid.


Handy Andy In Mt Airy NC

Re: Glaze or Caulk Windows?


If you'd like a window repair job in Winston Salem, please contact me at 919-623-3600.

Laughton J

Re: Glaze or Caulk Windows?

Thanks for the info carrie.

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