Caulking between PVC window & wall

Old 07-04-17, 11:19 AM
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Question Caulking between PVC window & wall


I am in dire need of help! I live in Ottawa Canada so cold winters.

The top front of my home is stucco so all second level windows (PVC) at front of house are surrounded by stucco wall.

I have a bathroom window at the front of my house that has the caulking between the window frame and the stucco wall that appears to be unsticking OR unsealing from the stucco itself. I will try to attach a picture of what is happening. From the picture, it is the window straight ahead. You will see that on the bottom right side of the window frame, if you zoom in, the caulking is peeling from against the stucco.

Name:  Bathroom Window caulking against stucco.jpg
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Name:  Bathroom Window caulking against stucco.jpg
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I've been quoted 100 to 120$ for this single repair by your run of the mill reno company. Since its such as small job, they have to charge me a base minimum fee to come out for the work....

That said, I'm willing to try fixing this myself first in order to save on some expenses. My only challenge is the fact that this window is on a second level but I should be able to reach the area by carefully standing on the garage roof.

Here are my questions:
What type of caulking material should I use for this job, considering that I am sealing the gap between my exterior PVC window and my stucco wall. (See pic) I want to use the MOST ideal and effective product that is most ideally suited for sticking on stucco so that this problem does not happen again. I've read about Polyurethane caulk, or Elastomeric?. I've read about using the brand Big Stretch or DAP Sidewinder??? I just want to know exactly which one to go pickup and use!

2-Seeing as how I am dealing with fragile stucco... Will it be hard or risky for me to remove the old strip of caulking from that one side of the window? Can I damage or rip off the stucco while attempting to remove the old caulk? Any tips or advise for removal of caulk against stucco?
3- Should I add a backer rod before applying to fresh caulk? If I remove the old caulk and notice NO backer rod, what are the guidelines for deciding if I need a backer rod or not??

I just feel bad paying someone 120$ to do such a job when I should be able to pull it off on my own. I just don't want to climb up there and work my butt off while using the WRONG type of caulk material. So that's my main concern. The caulk material.

Any other advice anybody can provide for such a job would be greatly appreciated!

Thanks again for any and all answers and tips. Much appreciated!

Last edited by PJmax; 07-04-17 at 02:39 PM. Reason: added 2nd pic
Old 07-04-17, 01:07 PM
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First, we can't tell much about the caulking from 20 ft away, even if we zoom in. If you can post a closer picture it would save us from speculating. (Can't you open the window and take a picture?)

Second, what you have is likely "EIFS", not traditional 3 coat stucco. As such, we don't know if the caulk is simply not sticking to the surface of EIFS, or if the surface of the EIFS has been ripped away from its substrate.

Additionally, it's not likely that the mfg's installation instructions for either product were followed to a T. Generally they recommend foam backer rod be installed between the window and the EIFS (or stucco, or siding, or trim, etc) since all building products expand and contract. Caulking also expands and contracts and caulking mfg's recommend their caulking bead be a minimum size and shape in order to work as advertised. Some codes spell out the details, others do not. I know you are in Canada, but as an example, see US code R613.7.5, ASTM E2112 and this document with illustrations that refers to them:

Finally, we have no way of knowing if this issue is being caused due to expansion and contraction, due to the method of installation (of either the window or the EIFS) or due to moisture... and whether or not that moisture is from exterior sources (rain getting in) or interior sources (condensation trapped behind the EIFS trying to get out).

So it's a little hard for us to just say, "yeah, recaulk it."... or "the bill is high because they need to redo the EIFS on that side of the window." (not likely or it would be WAY more than $120.)

BTW, $120 would barely cover 1 hour's time it costs the contractor to come give you your "free" estimate then 1 hour to go to the store, get the right caulking and return to caulk it for you.

To "try" and answer your questions...

If you were going to recaulk it, I would probably recommend either OSI QUAD or QUAD MAX, or if you would like a softer more pliable sealant, use Vulkem.

Yes, you can damage the surface, try to cut excess or loose caulk with a knife or possibly hook blade... you can use a sharp chisel and hammer but would need to be careful not to gouge the stucco. You usually do not need to get every speck of old sealant off, just the majority of it.

We don't know if there is backer rod. If there is a gap between the window and the EIFS, yes, use backer rod.

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