Recommended foam spray around windows?
ndege
| Posted in Energy, Heating & Insulation on
I’ve got major air coming in around new windows in a remodel. I plan to spray foam inbetween jambs and framing. I know there are several products that don’t expand a lot. Are any superior to others, either in R value or ease of application? How big of a gap can that stuff fill?
Replies
If you get an actual foam gun, you will have a TON of control over your bead of foam. I like the Dow Great Stuff for foam guns - it's also rated for fireblocking!
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
I'm familiar with the guns. Are those available at the Big Ugly Box stores? Or do they need to be ordered?
I got the Hilti gun (love it) at a Home Depot - but not all HD have Hilti tools.
Dow foam I had to get from a different supplier, but you can get conventional Polyurathane foam from Hilti as well.Rebuilding my home in Cypress, CA
Also a CRX fanatic!
i buy mine off ...EBAY usually pay $10- 20 ea... last week i got 2 delivered for less than $30... made in france... used one seems to do what it is supposed to do...
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I'm an ebay kinda guy...what exact foam stuff are are you getting?...if you don't mind sharing<G>I usually use the DAP low expansion stuff for windows and doors, but it is around 5 beans a can. Oh God said to Abraham, "Kill me a son"
Abe says, "Man, you must be puttin' me on"
God say, "No." Abe say, "What?"
God say, "You can do what you want Abe, but
The next time you see me comin' you better run"
Well Abe says, "Where do you want this killin' done?"
God says, "Out on Highway 61."
i use whatever i can get... greatstuff, hilti... alot of times you can get cases of it on ebay that have just hit the expire date... i think ... usually about $5 a can... I ran up on some black foam... main use i was told... was on chicken houses... but it worked well for me... I just about rely on the foam to hold my door and window units in... when you are dealing with odd size all brick openings that are 12-16" thick... I wedge the units in shim to plumb and foam em.... units i set this way when i was 17 are still there...
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great stuff also makes a window/door foam,its low-e comes in a blue can,
I have this and it works great.
http://www.energyfederation.org/consumer/default.php/cPath/21_28_1268
You definitely want to foam or otherwise seal around windows, if you're in any sort of climate where preventing air infiltration is important.
In terms of the canned stuff, any of the "low expansion" foams should work. The DapTex latex stuff is expensive and doesn't produce as much per can as the Great Stuff poly door/window stuff, but it's nice from the standpoint of not being a hazard to finished surfaces, and easy to clean off your hands. It does require longer to set, though, and should not be used where water might get at it.
DO NOT use any sort of "standard" foam -- no matter how carefully you work to control the amount you dispense, it expands too much and is apt to distort the window frames.
Can't speak to the bulk guns -- never used one.
I managed to find a pro gun (Dow) at a supply house. I put in Marvin windows. If you're familiar, they have a big gap at the bottom, 1". It's certainly stuffable with fiberglass, but what do you think about foam instead? Better? Worse? I've never used the foam, obviously,at least not in this application. And yeah, I'll do a little practice cause I love these windows and I'm not about to compromise them.
The big holes stuff with fiberglass and then top off with foam, to build up about 1-2" layer. The foam seals against infiltration much better than fiberglass.
People never lie so much as before an election, during a war, or after a hunt. --Otto von Bismarck
Yeah, I was thinking it would be better for air, too. So you're saying fill the outside part of the cavity with FG and then foam the front of the gap from the interior? I think it would make more sense to foam the outside part of the cavity to cover up the gaps and then stuff FG from the interior to finish it off. But maybe that's what you meant?
Either, depending. A remarkable amount of air seems to infiltrate THROUGH the window frame from the outside, coming into the rough opening gap. (Haven't figured out exactly how this happens, but it does, in my experience.) So my preference is to seal close to the inside. Your circumstances may be different, though.(Of course, you can fill the entire gap with foam, but fiberglass is cheaper and faster.)
People never lie so much as before an election, during a war, or after a hunt. --Otto von Bismarck
Ok Dan, I reviewed your post - where is the air coming in? Outside the window frame, or is it a window manufacturer defect?
I tape the sill, (6" tape) install the window, then I tape the flange to the housewrap all around using 6" bituminous (or whatever its called) tape. I am thinking this stops air infiltration almost completely, as I am basically extending the flange, and mechanically sealing it to the wrap (or ICFs in the case of my house)
My question is, after doing this, is there an appreciable difference between fiberglass and foam, since its dead air space. Or maybe you are advocating the belt and suspenders approach.
Treat every person you meet like you will know them the rest of your life - you just might!
I don't know where the air was getting in, but it sure was -- you could feel the draft. These were wood Andersen's, but in good condition and no obvious gaps in the frame. I'd think the typical plastic-wrapped frames would be no tighter. Outside, the window frames are carefully taped to housewrap, then hardboard siding is well caulked to the frames, so it's hard to claim it was blowing in around the outside edge of the frame.
People never lie so much as before an election, during a war, or after a hunt. --Otto von Bismarck
It sounds like the air is blowing in from behind the house wrap. If all the seams aren't taped and edges sealed there can be significant air flow behind the stuff.
Beer was created so carpenters wouldn't rule the world.
Yeah, except that all seams were taped and edges sealed.
People never lie so much as before an election, during a war, or after a hunt. --Otto von Bismarck
I could see the cumulative effect of all the siding nails, coupled with a large temperature, and therefore pressure differential between the inside and outside causing that.
Maybe the tape should go on before anything else, then the wrap, then the window, then more tape, being sure the house wrap stopped an inch or so short of the window flange and the top tape hits all 3. That type of sanwich should stop all infiltration.
Or foam away!
Treat every person you meet like you will know them the rest of your life - you just might!
Thing is, the wrap totally eliminated drafts through the electrical outlets. If the air was getting under the wrap you'd expect the electrical outlets to still have drafts.
People never lie so much as before an election, during a war, or after a hunt. --Otto von Bismarck
Thing is, the wrap totally eliminated drafts through the electrical outlets. If the air was getting under the wrap you'd expect the electrical outlets to still have drafts.
I'm relatively new to the tape solution, but I really like the stuff - I am thinking of getting an ebay foam gun - my gun is clogged, and I still have a case of foam - my basement windows aren't really sealed yet, and I'm planning to foam them in addition to the tape - if its worth doing, its worth over doing...
I've never had a window jamb bow b/c of foam, maybe I have been lucky?
Treat every person you meet like you will know them the rest of your life - you just might!
Sealing cracks is the BEST value in terms of controlling heat loss in a structure.
But PLEASE remember to check any fuel burning appliances to insure they are getting enough combustion air.
Downdrafting is not a good thing.
With an active wood stove as 99 percent of my heat source, I don't worry too much about a little draft. The aie has to come from somewhere. I truly believe the industry is producing unhealthy living conditions with air tight construction.
Ahhh, but did ya close the window.....? Hmmm.Ask you Hilti guy. I bought a case of Hilti foam and the guy threw in the gun gratis.The CF812 foam is low expansion pressure foam, made for window and doors.
Now, I walk around looking for gaps, holes, etc.Flexable cheap Japanese saw and a old serrated kitchen knife stays in the foam box for trimming.__________________________
Judo Chop!
To tell you the truth I've foamed around windows for a complete seal for so long that air getting by a window is something I just don't see or worry about.
Beer was created so carpenters wouldn't rule the world.
Regarding your Andersen windows.I've noticed that too.I've got the OLD 200 series Narrowline in the "old" part of the house (NON tilt-wash, NON low-e, and they have the weighted pullies or whatever with the cords on them).I've noticed that they seem to leak in two places:
Where the double-hung windows meet (maybe because they're old?)
and
On the mulled units where the mullion thingy is at.Now, I've got NEW 400-series windows on the addition and I can feel a *little* draft where the mullion is at. I'm wondering if Andersen actually insulated between the two windows or if they just slap the 1.5" or whatever covering over it. I'm tempted to pull it off (carefully since I already stained them) and fill in the gap with foam.
Now, I've got NEW 400-series windows on the addition and I can feel a *little* draft where the mullion is at. I'm wondering if Andersen actually insulated between the two windows or if they just slap the 1.5" or whatever covering over it. I'm tempted to pull it off (carefully since I already stained them) and fill in the gap with foam.
Did you caulk the gap between the mulled windows?
Treat every person you meet like you will know them the rest of your life - you just might!
If you have the Andersen 400 series window mullion units, you're going to have air leaks. I did a house full a while back and noticed that air infiltration . Called andersen about it and they said that they don't insulate between the mull units. I asked them what the heck would a peice of 3/8 foam cost based on the cost and energy eff. and reputation cost??. They said I was the second person ever to notice that and they would get back to me as to what they could do about it. I'm still waiting. We mull our own units now instead of the factory. <!----><!---->
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Anyone use "backer rod" for the big gaps? Don't know what it may be really called. Thats the term we used in bridge maintenance to cork up the joints before filling with epoxy. Foam and comes in various diameters.
I often use backer rod to fill big gaps and then foam after. Less foam expansion to rack the windows.
I think foam backer rod is the real name, but if you go to a big box they'll just look at you funny. "Caulk Saver" is what it is called when you have to get it in the little bags. Bulk is better, but I don't need a 500' roll of it.
The larger diameter stuff we used was maybe 8 foot lengths (1 1/2 and 2 inch dia.). Check out a bridge contractor - maybe you can purchase only te amount you need.
You can buy it by the foot in all kinds of diameters at any concrete supply house, and they have 3/8" upto probably 1" at least.Cheap, maybe $.10 a foot or less maybe.JT
In my experience, the non expanding foams never really cure. I would avoid them. Gun foam is truly great.
Related thought: If you use window tape on the outside, does it make any difference if you stuff fiberglass or spray foam? Won't the tape take care of any air infiltration issues?
See my post. In my experience you get infiltration through the window frame itself.
People never lie so much as before an election, during a war, or after a hunt. --Otto von Bismarck
By window tape, do you mean a waterproofing wrap? Ice & water or the like? In my case, I haven't got that on as I haven't trimmed out the windows yet : ) I tossed tar paper & plywood scraps over the gaps on the exteriors. So I'm sure you're right. Obviously, I should have done this job months ago! You know how it goes, though.
I buy the Great Stuff in the red can when it's on sale for $3 a can. I don't try to fill the void the first pass, just lay in a SINGLE BEAD that can expand as much as it wants while attaching itself to both sides. This has the advantage of holding the jamb firmly without deforming it.
Once that is set up hard, i go back and lay in a bead each on the inside and outside. The previous bead keeps any subsequent foam from pushing the jambs away from the trimmer stud.
I also use this technique on interior doors, which makes them close so much more nicely.
Stay away from DAP. THeir window crack fill is like shaving cream. I used it in a garage application and rain decayed it dramatically. However it does leave a clean shave.
Yes, it shouldn't be used where it would likely get wet. It's very slow setting (probably weeks), and is susceptable to moisture until fully set.But the water cleanup feature is a major benefit when working around finished surfaces. The Great Stuff type foam will damage just about any finish it gets on.
People never lie so much as before an election, during a war, or after a hunt. --Otto von Bismarck
That's where that blue painters tape comes in handy.Rebuilding my home in Cypress, CA
Also a CRX fanatic!
The foam is a good idea, but you could also use caulk and some rope caulk in expansion sensitive areas.
ndege,
One bit of advice. Wear gloves.. that stuff on your hands when it dries doesnot wash off, it wears off, far better to throw away a pair of cheap gloves than have that stuff on your hands for a week!
If you've never had a foam gun get a cheap one to start out with. They wear out quicker and can be a little harder to work with, but not much. The main advantage to not going with a top of the line gun such as the Hilti right out of the box is some people are either too rough with them or they simply can't remember to keep a can with at least a little foam left in it attached at all times and the gun is toast.
The cheapest economy gun at http://www.jrproductsinc.com/foam_guns.html is good for most purposes.
View Image
The Dow Gaps and Cracks foam is as good as any I've used ( http://www.jrproductsinc.com/foam_kits.html ) and we use it for everything including windows and doors, but you have to be careful or it will spring your windows.
The non-expanding foams are much more expensive since, well, they don't expand. By careful use of the normal foam you won't break the pocketbook by always have a foam gun handy.
To use regular foam in windows and around doors the trick is to not fill the gap completely with foam in one pass. Corners don't flex so they can essentially be filled from exterior to interior on the first pass. Same goes for any areas held tight to the framing by screws.
For the more flexible areas that would be damaged by expanding foam I tell carps to only apply as much as will expand to fill half the cavity along the exterior of the window and no more. If in doubt just use a very small bead and watch to see how it expands. Small beads dry pretty quick so it's not uncommon to come back in an hour and be able to apply a second layer.
Hopefully, this first layer will have some large gaps and only a few small spots that will expand to actually bridge the gap. With so much room to expand there is very little pressure being exerted on the window.
For the second layer only apply enough foam so it expands to fill half of the remaining gap. Again, by allowing plenty of room to expand there is very little pressure being exerted on the window. As much as people try, there will be quite a few areas that have bridged the entire gap. It's ok but don't push it.
On fragile windows such as Marvin Integrity double hungs (a terrible window) I'd try to use at least 4 passes. These are probably the only windows I'd actually use non-expanding foam on. The sides of these windows are very flexible, especially if they are tall and even with the utmost care I've had problems.
Before you get the hang of using normal foam on windows you might screw up, or you might have an extra flexible window that gets you into a bind. Simply use a pruning saw or coarse bladed japanese pull saw and cut a slit in the foam near the window to releave the pressure. Once the pressure is releaved apply a small bead of foam to seal the crack.
Excess foam that squeezes out is easily trimmed with the same japanese saw used to cut cedar shims flush.
A technique used in colder areas overseas is to suspend the window in the opening with screws and essentially hold it in place with a continuous layer of foam. By eleminated or reducing shims to a minimum there is more room for foam and more foam means a higher R-value.
I've been using fewer shims and the results seem to be good. I'm running screws from the window to the framing, but the heads are counter sunk and just tightened enough to take up the slack. Essentially the window is sitting on two shims along the bottom corners and is suspended in the opening. The foam layer around the window is quite strong and I'm convinced this is a better way to seal the space and maximize insulation.
We're also framing our rough openings a little larger than normal so it's easier to get the foam gun into the space. More foam is more insulation. It also allows us to suspend the bottom of the window on a few shims or blocks so instead of a hard to seal hairline gap, there is plenty of room to get foam clear out to the exterior.
We've recently changed our headers to a sandwich of LVL/ 2" of ridgid foam/LVL held together with 6 Timberloc screws. When foaming around windows with these headers we have a significant thermal break.
If the LVLs are slightly wider than they should be we use an electric hand planer to shave 1/8" or so off the foam so the sandwich ends up the ideal thickness.
Good foaming
Beer was created so carpenters wouldn't rule the world.
Nice link to the foam guns...
I've had one for years, it's one of my favorite things ;-)
Don't do enough windows to have modified my RO/installation techniques, but if I did, I'd follow your lead (hope we don't find out 20 years down the road that the foam disintegrates...)just a thought, with the nice flashing tapes available now, do you wonder if all that foam is overkill?
just a thought, with the nice flashing tapes available now, do you wonder if all that foam is overkill?
Not at all. Even if the flashing tape would seal 100% we'd still foam the gap for the insulation value. There is also very little chance of a flashing tape sealing 100%. :-)
Beer was created so carpenters wouldn't rule the world.
There is also very little chance of a flashing tape sealing 100%. :-)
I am wondering why you say that (or do I misread the intention of you smiley) - the potential for a complete seal is why I use the tape in the first place. Where do you see air entering?
For instance, I tape the sill, install the window, then work from the bottom up, sealing the window flange to the house, using a heat gun to warm the tar (or whatever that black stuff is) On our house, the tape covers all the way to the ICF foam, and tape is over tape at each corner. (no house wrap here) I tape over the wrap on standard construction. I guess a sandwich (tape before and after installation) could make certain there were no drafts.
As an aside, I have a lot of contractor friends, but I'm the only one who ones a foam gun - not many folks are thinking this hard about window air infiltration...
Treat every person you meet like you will know them the rest of your life - you just might!
Where do you see air entering?
On verticle surfaces getting a long-term seal can be harder than it looks. Just today a verticle section of ice and water that was applied under ideal conditions and appeared as if it would stick forever, simply fell off. A little mild heat softened the bond and off it came. What happens in the heat of the summer, and in direct sun to the tape we seal windows with? Usually nothing, but how many window installs do we get a look at years down the road? If anything it's small areas that will come undone.
Yesterday we tried some primer and the results were encouraging. Now if there is a question of it sticking we'll brush on a little primer.
Window tape is good, but we still like those secondary lines of defense.
Happy Holidays :-)
Beer was created so carpenters wouldn't rule the world.
Great points.
What is this primer you are using?
Treat every person you meet like you will know them the rest of your life - you just might!
There is a primer recommended by Grace in the installation manual that is probably the ideal choice.
What we are using is a primer sold to bond expanding concrete waterstop to dry concrete. It also provides a very sticky surface for the ice and water shield.View Image
I don't recommend this stuff if you can get the regular primer since it's $70/gal, but we'll use it up before getting anything else.
Beer was created so carpenters wouldn't rule the world.
I have also seen that happen when the vycor "sloughs" off from the sun's heat. I take a few red head nails and place them in strategic positions to hold it on and yet not compromise the seal around the window. Make sure the top is flashed under something!
Sorry about the file size, got to get busy...