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I just did a caulking search and can’t find an answer for this one.
I am renewing the caulk joints on a commercial building. The structure is CMU with 1″ rigid foam, air space and brick veneer. The windows are your typical fixed store front variety alum.
The problem I have uncovered after removing the old caulking is the gap between the window frame and the brick. This is some of the sorriest brick work I have seen in some time, and as you might guess, the brick to frame gap varies a lot. In addition to that the rigid foam was broken back sometime 3 to 6″ from the block opening. Quite simply there is nothing in there to catch the styrofoam “backer rod.” I pushed 6′ of 1/2″ rod into one 14″ x 3/8″ gap only to watch it disappear.
I am thinking about using “Great Stuff” to fill these voids.
What are the pros and cons of this idea? Any other thoughts on what to do would also be appreciated.
Dave
Replies
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I would do the same. It will do the job of filling as well as insulating.
Gabe
*Dave, Just make sure you get all the Great Stuff covered with caulking as sunlight will cause it to break down over time. And whatever you do, DON'T use the water soluible stuff made by DAP because it sucks big time! Excuse my way with words but thats how well the stuff works.Mike
*If you can wait a few days, (sounds like maybe you can't) now is the time to buy that real foam gun we've been talking about. Still one of my all time favorite tools. http://www.efi.org
*Thanks to all.lonecat, you are right. At this time I am only doing four windows on the south side of the building, and they have to be finished today. I examined the the west side yesterday and found it to be in pretty sorry shape, but it is not leaking at this time. It seems that no matter how many time we raise a red flag on something, this company will not take a proactive approach to building maintenance. Maybe when those store front doors and windows start leaking I'll get the foam gun. They always seem to have the money to purchase tools and make repairs when things go critical.Micheal, I'll be using a regular foam, and masking off the brick and window frame to avoid any overfill that could stick to them. I thought about the DAP, but haven't read a lot of good stuff about it here or anywhere else. I am using a urethane caulking made by Tremco for metal frame applications. I have seen spray foam break down in sun light. What an ugly sight!Thanks Gabe. Sometime I don't see enough alternatives when I look for a solution to a problem. Your endorsement at least assures me I did not miss an obvious one this time.Thanks agian,Dave
*Dave, Don't do this. Backer rods are available in widths up to at least 2". Your problem is that you are not using backer rod that is wide enough. We have a few commercial suppliers in our area which stock various backer rods for this purpose. Another place to try is a local commercial caulking and waterproofing contractor. For something small like this, I am sure they would sell you some rod material. The problem with using urethane caulking over "Great Stuff" or other expanding foams as backer rod is that the solvents in the urethane caulking react with the expanding foam. I tried this about 7 years ago and found that the urethane caulk never set up properly. The other problem was that the expanding foam started expanding again and caused large bubbles to form in the caulk.
*Tim, where were you at 4:30 this morning?I have already foamed the deep cavities around the windows, but fortunately did not fill them up. I left enough room to install backer rod, if that foam dosen't grow overnight. If it does, I'll rake it out and get the backer rod in there to keep the caulk from touching the foam.I have rod up to 1", but I don't think it will fit through the 3/8 to 1/2" gap at the brick/frame joint.The rigid foam agianst the block is 2", and in some places missing as far back as a foot from the edge of the window frames. All I am attempting to do with the foam is give the backer rod some place to land,other than the bottom of the cavity.Thanks for the advice.Dave
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I just did a caulking search and can't find an answer for this one.
I am renewing the caulk joints on a commercial building. The structure is CMU with 1" rigid foam, air space and brick veneer. The windows are your typical fixed store front variety alum.
The problem I have uncovered after removing the old caulking is the gap between the window frame and the brick. This is some of the sorriest brick work I have seen in some time, and as you might guess, the brick to frame gap varies a lot. In addition to that the rigid foam was broken back sometime 3 to 6" from the block opening. Quite simply there is nothing in there to catch the styrofoam "backer rod." I pushed 6' of 1/2" rod into one 14" x 3/8" gap only to watch it disappear.
I am thinking about using "Great Stuff" to fill these voids.
What are the pros and cons of this idea? Any other thoughts on what to do would also be appreciated.
Dave