No expanding foam around windows – why?
Redwood Curtain
| Posted in Construction Techniques on
The install instructions on all the new windows I’ve just installed (vinyl) say not to insulate around the windows with expanding foam. Why not? Seems like a low-rise foam would be the perfect choice. Thanks.
Replies
You just don't want to pinch the middle of the sides in. The low-rise Great-Stuff foam (light blue label) does say it's safe for windows.
If you're concerned, I'll bet you could make some tight-fitting sticks that would press-fit between the inner jambs for the duration of the curing.
Forrest
I thought that might be it. I'd think that cautious application would be fine - thanks.
Yeah, what Forrest said. The liability department writes this stuff, because too many careless foam applications have resulted in warranty claims on vinyl windows.
Done right, foam is the best way to go. Not only does it insulate, but it also helps to airseal and also makes the installation more solid.
Bill
i've heard people say that spray foam such as "great stuff" may exert too much pressure on the jamb and prevent the window from opening/closing/operating properly... but i think this has to be some sort of tale to excuse an improperly squared and installed window. spray foam just doesn't have enough density to force a properly secured jamb. 4# pour foam could easily do it but the stuff from the can, in my experience, is pretty weak... i may be wrong but in the times when we've not installed our own windows and had professional window installers out to jobsites, they've always finished up with spray foam and there has never been a problem i could attribute to the foam.
I beg to differ, Scott - lol.
The first time I used foam around a window (sometime in the early 90's, IIRC), I used the high expansion foam (Great Stuff in the red can.). I probably oversprayed it because I had to scrape off quite a bit of squeeze out, but the window froze up tighter than Dick's hatband. After the boss got over his mad, and I had scraped the damned stuff out, the window worked again.
I don't think that they made the low expansion stuff then and we had to spray the stuff in light layers so it wouldn't bind the windows.
Edited 10/9/2007 12:09 am by Dave45
scottbuilt,
Great stuff makes several types of foam from big gap filler thru the low expansion stuff for windows. I've had to go back when I used the wrong stuff and cut back the foam a bit to allow the window to slide up and down properly. On really tall windows such I used, foam can squeeze the window in the middle by more than 3/8ths of an inch if you use the wrong variety..
Not a big deal if you catch it before the molding goes on. a sawzall blade makes quick work cutting the foam away enough for the window to work properly. I wrap a little tape around it to protect my hands because you do not want to do this with the blade still in the saw..
Yeah, the regular Great Stuff can easily distort a window frame if not very carefully applied.
If your view never changes you're following the wrong leader
i suppose it's possible... must be some cheap windows or some poor installation. i can't believe regular great stuff has the force to move a 3/4" pine board that is secured to the framing. i guess i'll have to see it for myself... but i'll use the foam sparingly next time just in case.
Great Stuff can most assuredly move a 3/4 pine board.
I think the bigger question is how will the finish carpenter get his shims into the gap behind the jambs if they are stuffed full of hardened foam? Do trimmers ignore the need for shimming and nailing the jambs nowadays?'
jimfka (formerly known as) blue
i'm sure plenty of them do... i always do more than i need to but i enjoy the process. as far as shimming out extension jambs, etc. foam has never been a bother... it's pretty light. at least the stuff i'm used to.
Sorry to say most finish carpenters don't know how or where to shim a window... or even if the window requires shimming or not. You'd be surprised at the number of window and door problems 10 years down the road strictly resulting from improper shiming. I know one local builder that has easily installed 2000 windows in the last 5 years. Not a single one of them was installed per instructions and I gave up trying to correct the problem through education. He knew the proper way to install a window and instructions were for idiots... all you had to do was ask him. The upside is next month he will finish his last house and be officially out of biz... opening a very lucrative market for me.
The hardened foam IS the shim
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
<hardened foam IS the shim>
Yeah, and yer seat cushion is a flotation device
Forrest
McDesign,
don't poo-poo the strength of great stuff!
I built my home using SIP's Great Stuff. It's a normal part of building with them. I had a lot of panels sitting around late one fall and rather than simply stacking them in the yard to be installed in the spring I put them on the roof where I'd need them next spring. I had only limited access to the big 54 foot telehandlers used to put them up on the ceiling of my second story.
Anyway one thing led to another and when the spring rolled around I had decided to move a tower from the first level in the driveway to the 2nd floor . I wound up cutting panels I'd already installed away before I started building. I had a helper lift up timbers and such to me and had directed him to cut panels away in order to get the timbers in place.. these where heavy tamarack timbers and eventually they got too long and awkward for me to handle them by myself. I called my helper up on top of a panels and together we lifted the rest of these heavy timbers up and into place.
When I climbed down I was shocked to discover just how much of the supporting panels had been cut away..
The panel the two of us had been standing on was almost 7 feet long. Two guys with a combined weight of nearly 500 pounds plus the weight of those heavy timbers had been standing on the panel held in place solely with great stuff. No nails, no screws no supporting members just foam !
Piffin,
I must confess my fundamental mistake when I installed a large bow window using Great Stuff.
I was extremely carefull making the rough opening the correct size, plumb, and square, because I understood just how difficult it would be to set this large bow window up on the second story. It was large to allow the maximum light into a bedroom on the north side of the house and I worried that it might be too gloomy.
Accordingly I made the window as large as legal and in order to provide the required minimum height I had to place it right at the top. I used one of my Telehandlers with a swing carriage and raise it right to the correct position and it slide in so nicely. plus when I put a level on it was extremely pleased that it was level and square without the need for a single shim..
I went ahead and nailed it in place and then foamed the cavity that remained
This was just before a snow storm hit So I was really rushing things, last opening to be sealed before winter etc.. It would have helped if I had a few moments but the storm had already hit and the forklift had to go back.
This summer when things were getting a little hot I decided to open the windows in the bow to capture a nice cooling breeze coming by the house..
and well OOP's!
Unlatched the catch and cranked on the window and clunk! it opened maybe an inch and a half and hit the beams coming out from under the roof..
Foamed in place the window was too high by over three inches and won't open.. Only a shorter window will open. the foam and time made it so I can't return the window.
My suggestion which I ignored because it went in so nuce and easy and time was so critical is always open your windows before you foam them in place.
Nice view out a fixed window with handcranks.. ;-(
Nothing a chainsaw won't fix.
If your view never changes you're following the wrong leader
I was trimming a job that was foamed and all of the pella wood windows bowed at the top from too much foam so bad you couldn't close and latche the double hungs.
had to put a long course blade in the jigsaw and dig out about half the foam.I've had good luck with daps brand of window and door foam - latex based, easy cleanup, expands slower and cures but stays compressable.another thought as to why the foam may not be for vinyl replacements is that there are holes where the screws are to be installed through the side jambs of the windows. maybe they have had experiences in the past of foam coming into those holes mucking up the works. or perhaps even there might be a chemical reaction issue.
I'd call the rep from the window manufacturer and ask why."it aint the work I mind,
It's the feeling of falling further behind."Bozini Latinihttp://www.ingrainedwoodworking.com
Yeah, the solvents in the standard Great Stuff are apt to attack plastic.
If your view never changes you're following the wrong leader
Pella dblhngs have that problem without foam
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
LOL"it aint the work I mind,
It's the feeling of falling further behind."Bozini Latinihttp://www.ingrainedwoodworking.com
It ain't the work I mind, it's the fact that my boss expects me to be awake to do it.
If your view never changes you're following the wrong leader
my tag line is from my cousin's album. he was a folksy singer. last year he passed away and it's a nice little reminder for me of how much I enjoyed his company.
A real special guy."it aint the work I mind,
It's the feeling of falling further behind."Bozini Latinihttp://www.ingrainedwoodworking.com
"this has to be some sort of tale to excuse an improperly squared and installed window. spray foam just doesn't have enough density to force a properly secured jamb."That would be an incorrect assumption.I have been successfully using can foam for window installs for a hundred years, more or less ( OK so I exaggerate a bit) But I have also seen some pretty funny disasters from DIYs trying too hard. You really can bow a window frame in 3/8" per side and stop it from operating
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
how hard is this foam you're seeing out there?.. the spray stuff i am familiar with is pretty wimpy. and if the window is closed when the foam is sprayed how does it bow the jamb? does the foam you use continue to expert pressure on the surrounding surfaces after it's cured?
You are confusing me with the other ones I have seen and reported on.I use a low rise foam and place it only near the very exterior of the wall, near the nailing fin. Add a dab here and there or at corners also.The ones I have seen damage windows are the DIYs who try hard to fill the whole space with regular foamThen they leave and go away and then are amazed later to discover they hvae a pillow growing out of the wall.The deflection in the frame happens thus - As the foam grows and puts pressure on the frame, if billows into the room interior. The window frame is nailed tight ( well, sometimes not all T?HAT tight, LOL) so it can't move much near the exterior surfaced of the wall, but the frame can flex away from the jack studs towards the center of the window.
So you end up with a twist going on. Since this is all variable and nmot exactly the same all around the frame, it can put uneven stresses on the frame and then it yanks it out of square relativve to itself too.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
The contractor extending the fishing dock near me used spray foam to secure the foam bales in place as he was installing them. Until he got the hang of it, he used too much and popped the new 2x4 decking he had just nailed down.
I've had a drop-in tub I couldn't keep down, even with me in it, as the foam underneath expanded. I'm sure window frames are no match for the power of foam.
I once saw a carp overfill vinyl windows with great stuff. As we were siding the building we heard a loud crack. We went to investigate and as we came around the corner another crack. long story short by the end of the day 7 of 22 windows needed replacement. Yes it actually shattered the glass.
That is one for the books, no doubt about it.
If you foam, the warranty will be voided. Beware.
I put a window in my own house once and took great care to foam it so no pressure was exerted on the jamb. The dang thing leaked cold air till I cut out the foam and pushed insulation into it.
I've seen foamers foam windows and bow them in. The bricklayers followed up and bricked tight against the bowed in jambs. The windows don't operate properly and the builder can't figure it out....
Good grief.
jim
fka (formerly known as) blue
I've seen foamers foam windows and bow them in. The bricklayers followed up and bricked tight against the bowed in jambs.
Holy Cow! What had to be done? The window removed and replaced with a narrower and customized trim?
Rez, that situation was done to some Anderson windows that we had set. The builder called me back to complain that the windows didn't operate properly. I pointed out that we had nailed the chintzy plastic fins exactly to manufacturers specs and installed them plumb level and square and it was his own employees who ignored the written instructions that were still visible on the window. I also pointed out the instructions that required 3/16" gap for all masonry. I asked him if perhaps he might consider calling the insulator (his employee) and the mason back and discuss the installation techniques with them instead of me.
He then decided that maybe I didn't do anything wrong except for one window. That particular Anderson window was visibly not aligned. It took me a few seconds to determine that it was not a parallagram. The head jamb was 1/4" longer than the sill.
When I left the site, he still wanted to blame me, the carpenter for everything. I can't explain it other than it seems logical that if a window doesn't work, the carpenter must have installed it wrong....no matter what the reality is.
I have no idea what he did...probably nothing. I never did another job for the guy. He was one of those absentee superintendents that was too important to pay attention to his job.
jimfka (formerly known as) blue
I just had every one of my windows foamed by the insulation contractor. Here in Southern CA is a code requirement. In fact, they alo ran a small bead of foam along the entire ground floor perimeter plates where they touch the sub-floor. I don't understand that one.
Anyway, there are different foams. I forgot the name of the one they used, but I do know it's the least toxic one- I think it's latex. The foam did epand a little, but it bubbled out the gaps along side the windows (mine are all vinyl). Don't worry, the foam will take the path of least resistance.
Besides, the stuff is pretty soft. I know because now I'm cutting and scraping back all the excess so my wood jamb extensions can sit tight to the windows.
Jim
I use plain old "Great Stuff" cuz it's cheap when it goes on sale every fall. I put a bead around all the windows, let it set up a few hours, then go back and fill in. A bead that expands just enough to glue the jamb to the structural material will fix the jamb in place without bowing it; subsequent filler won't budge it.
If you have ever tried to adjust a window due to settlement or bad installation you will hate the day you run into foam insulation.
expanding foam works great for some things. As far as I'm concerned windows are doors aren't included.
Use backer rod. It's that spaghetti like foam that is a direct relative of the "noodles" that kids play with in the pool.
I've installed many windows and have always used foam. I do run into the occasional stuck window, but it's usually not the norm. And it's usually nothing that can't be fixed. Done carefully without stuffing the jambs I've found spray foam to be quite effective.
No expanding foam around windows - why?
hello
I was just wondering if insulation foam can expand in dry conditions around a window (frame) and cause warping and damage to the window up to and including breakage. I have seen it warp a window frame to the point that makes it difficult to operate, but, I have not seen it expand to the point it breaks a window.
Depends on the foam. The purpose-made stuff is light and soft enough that it couldn't cause damage if it wanted toz.