# Caulk bubbling/sinking on vinyl windows...



## AllGoNoShow (Aug 8, 2006)

Just replaced 18 windows in my house with Seaway vinyl replacements. I used colored OSI Quad caulk as it seems highly recommended. I've noticed that on some windows (typically ones which get sun), the caulk looks excellent when I do it, but over the course of a couple days it develops large bubbles in spots that look terrible. Other windows develop a line in the caulk which looks like caulk squeezing out when the weather is hot then it shrinks and sometimes goes away when it is cold.

I had to caulk where my new exterior stop flashing meets the old flashing and this spot looks awesome, the problems just develop on the caulk where the stop meets the new windows( like it is something with the two different materials expanding/contracting). One of the large 65" windows in the garage that sees a lot of hot sun I've recaulked 3 times with same results (only does it in the middle of the window where there is a 1/8th inch gap. Never had any problems with caulk like this before. Ideas?


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## Wildbill7145 (Sep 26, 2014)

Are you applying it when either of the surfaces are hot, or even warm to the touch? I've seen that happen with some thermoplastic sealants and some latex caulks before when applied in direct sunlight.


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## CompleteW&D (Sep 4, 2015)

Some pictures would help....


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## AllGoNoShow (Aug 8, 2006)

This is a window that is in an unheard garage that I've recaulked 3 times with same issue. The last time I just tried pushing in the bubbles and then reapplying the caulk with the same result developing a couple hours later. There is an 1/8th gap here


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## CompleteW&D (Sep 4, 2015)

Ok, I'm even more confused now than before (which isn't saying much.... LOL)










I see what looks like a "twin" window opening with the window on the left sitting where it should in the opening, but the window on the right sitting several inches back in the opening. It "looks" like you are trying to caulk along the parting stop of the old window. Although, it's pretty hard to tell because you can't see much from that pic. (maybe one from a little further back would help?)

Anyway, like I said, I can't tell from that pic exactly what's going on. I actually had to enlarge it to see the window on the left.


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## AllGoNoShow (Aug 8, 2006)

The depth is the same on both windows, just how the picture looks. The old windows had storms attached to the exterior stops with the window flashing extended to the storms but not covering the exterior stops. Once the storms came off I had the wood exterior stop exposed so instead of re wrapping the whole window I just had an L-shape piece of metal bent to cover the wood exterior stop. The first caulk line to the left is where this new flashing meets the old flashing (this caulk on all of the windows shows no problems). The second caulk line ( with the bubbles) is where the exterior stop meets the new vinyl window.


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## fortunerestore (Mar 6, 2014)

Even I am not sure for the pictures. The windows appear to have a twin window opening, which is bit confusing for me. In case you are applying it when the surfaces are hot or a little warm, you can use the thermoplastic sealants. And also if you are doing it in the sunlight you must go for some latex caulks.


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## Jmayspaint (May 4, 2013)

Could be air pockets behind the bead. Are you using a backer rod? If the crack has voids in places behind the caulk, the drying/curing process of the caulk can cause increased air pressure in those voids. This pushes the caulk out and makes a blister. 

Instillation of a backer rod, or other material to pre-fill the voids before caulking can solve the problem. If that's what's going on anyway.


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## carpdad (Oct 11, 2010)

There was a post about the sealing tape (or was it caulk) melting around the windows. It was due to a chemical reaction between different materials. I think the point was not to use sealers made with butyls.

I used OSI for a while now and never saw such a problem. But if it keeps happening, I think some kind of chemical reaction may be your problem, if the caulk is not curing. If OSI remains soft and dents easily with finger pressure, try calling the maker.

For the OSI to bubble, you may be skimming the caulk too thin. If you had to fill a wide gap, for example, and skimmed it. If you have a vinyl siding, water is probably getting under it and steam could be the culprit.


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## kwikfishron (Mar 11, 2010)

I've had that bubbling issue (on occasion) with Quad before. It seemed to be more of an problem when it was applied and left to cure in the direct sunlight. If you Google "OSI Quad bubbling" you'll see you're not alone.

I've always preferred Vulkem 116 over Quad. I've never had that issue with Vulkem.


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