Caulking Windows


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Old 11-28-09, 05:41 PM
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Caulking Windows

Mainly I'm trying to decide between latex and silicone caulk.

I have white aluminum windows, and my 1987 budget builder house is mostly vinyl siding except for a brick front on the first floor only. The brick windows have never been caulked. I have a caulking gun and know how to use it pretty well. I have done a lot of interior latex caukling, but I have never used silicone.

How much longer does silicone last? Do you still smooth it with a finger (while wearing vinyl gloves) or do you use a smoothing tool? Some of the spaces near the brick are greater than 1/4, so I assume I will need some backer rod.

I have seen many examples where this builder cut corners. Should I suspect that he didn't put foam sealant around window? From outside, I can see through the brick gap to the window flanges, and I don't see any sign of foam. I know what a pain that foam can be to clean up, so I don't want to add foam from the outside unless it really sounds necessary. I would want to mask window and brick prior b/c I don't trust myself to be that neat. I know I should probably use the minimally expanding foam, but is it safe to use standard foam if am careful to only lay a small bead? (I have some leftover foam that isn't sealed shut, and I only have 2 windows on the brick front.)
 
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Old 11-28-09, 07:34 PM
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I would advise against doing any caulking, and for several reasons.

The idea to foam the window from the outside is a bad one. There is no point in doing this. The window will also not be any tighter if you caulk the window to the brick. The main place to insulate a window is behind the interior trim, between the window and its rough opening. If you caulk and/or foam the exterior, all you will succeed in doing is making a mess. I've seen homeowners do it a million times. They ought to have a 7-day waiting period to buy caulking guns. LOL (even if you mask it and tool it, you'll probably still get it all over.) If you use silicone, the silicone will attract dirt. Latex caulks also attract dirt, but to a lesser degree. Provided the builder used 30# felt behind the brick, you don't have much to worry about when you have the occasional driving rain. A brick veneer is not waterproof to begin with, which is why you have a 1" airspace between the brick and the sheathing, to allow for drying and to eliminate most capillary action between the two surfaces.

So I guess having seen 1000's of homeowner caulk jobs, ESPECIALLY against brick, my first instinct would be to try to dissuade you from doing it. Especially since the benefits are next to none, other than for cosmetic reasons. And if it doesn't look nice when you're done... well that kind of defeats the purpose of attempting it in the first place.
 
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Old 11-28-09, 09:28 PM
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Thank you.

I have no desire to do any king of window caulking just for cosmetic reasons. So unless another experienced person, makes a strong case for an actual energy loss savings by caulking these windows, the "do nothing" option works just fine for me.
 
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Old 11-29-09, 04:52 AM
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I have caulked 100's of windows to the brick [new construction]. I always thought it was a code requirement but it may have just been a requirement of some builders. If caulking the window makes for energy savings - there are more problems with the house construction. Unless I'm mistaken, the foam insulation is only used on the inside.

I've probably used more latex caulk than silicone to caulk windows to brick. I would think tape would give a false sense of security given that tape doesn't adhere well to brick and dealing with the mortar joints would be a royal pain in the !!! It takes a fair amount of skill with a caulking gun to do a nice job against brick. If you lack the skill to do a neat job, I'd suggest using a clear caulk - either silicone or latex..... but if XSleeper says it doesn't need to be caulked, I'd consider that as well
 
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Old 11-29-09, 05:09 AM
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Whether you decide to caulk or not I have a comment on silicone sealers.
Silicone does last longer than latex by my experience but it will eventually fail.
When it does it still sticks tenaciously in many areas and makes a mess when you try to remove it.
I find that all things considered latex with its slightly shorter life is easier to clean and is better long term.
 
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Old 11-29-09, 10:04 AM
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Just stay away from low quality latex caulks.Gravitate toward latex silicone blends and buy as high a quality product as you can and as your retailer carries.

Latex silicone blends have a longer life,more mildew resistance but not the removal and application issues of all silicone products.They are paintable.most all silicones are not ( a few are and will say so speicifically,if it's not on the tube it isn't paintable).

I would tend to agree that inside around the window is a better point of seal than outside however leakage around a window from the outside and assuming little or no effort was made to seal around the window in the wall etc,can lead to cold air flowing into the wall itself and entering the home through electrical switches and receptacles and other similar points.
 
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Old 11-29-09, 12:16 PM
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My point about not caulking, was that caulking the outside edge of the aluminum window frame (which is 1" away from the nailing flange) on a brick veneer will do next to nothing to stop air infiltration. Any other type of siding, yes. But since brick veneer is open at the top, wind can move behind the brick in that 1" airspace whether the perimeter of the window is caulked or not. When you have a brick veneer, caulking would only be to keep water out in the space behind the brick veneer... and for looks.

GregH makes a great point though, latex caulks are easier to remove and replace too. And like spdavid, I avoid silicones because they are generally speaking, not paintable. Not that you'd be painting around a brick opening anyway, but it's good to avoid silicones for most exterior work that needs to be paintable.
 
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Old 11-29-09, 12:56 PM
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IMO it's never a good idea to use cheap caulking. Some of the cheaper caulks will turn color as they age unless painted but mainly the cheaper caulks don't have the flexibility they should have. Your better brands of latex caulk will say - siliconized acrylic latex caulk, which is paintable.
 
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Old 11-29-09, 04:08 PM
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Something that has always kind of bugged me is that some people (my boss is one of them) think that clear caulk means it is "invisible to the naked eye". LOL Sad to say that's not the case. A crummy job of caulking, done with clear caulk will look almost as bad as a crummy job using any other color of the spectrum! I guess it is "less visible" but not INvisible. heh heh!

At any rate, if I were going to caulk such a window, I'd use Vulkem 116, which is actually an oil-based polyurethane sealant. It's not a silicone and not a latex. Sticks very well to both masonry and aluminum, has good elasticity as an expansion joint, and has a nice grainy texture. It can also be tooled nicely using paint thinner in accompaniment with masking tape to contain the mess. Although tooling it smooths out the grainy texture somewhat. The color of the caulk should best match the brick. *If* you decided to caulk for appearance / or to prevent water intrusion around the window.
 
 

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