Insulation options?


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Old 03-26-08, 08:47 PM
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Insulation options?

Had a customer the other day who requested spray in foam around the new window units. I have been taught to use fiberglass and would like to hear everyone's opinion on insulating around a new door/window. I know about min. expanding especially for doors and windows, but hard to teach this old dog a new trick, and have yet to hear from a manufacturer that they recommend it. Comments? Please.
 
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Old 03-26-08, 09:05 PM
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For the last 10 or more years, we have only used low expansion foam around windows and doors. Fiberglass slows air, but does not stop air, and the only place we use it is between studs to replace / repair existing fiberglass. So if there's a 35 MPH breeze blowing, outside, you'll feel it through the fiberglass. If you would foam this same gap, you would feel NO air. That's enough to convince me which is better to use. I assume the foam is also an effective vapor barrier, which is a plus around a window or door where you have the potential for air exchange and condensation due to air leakage.

As far as what manufacturers recommend, I can't speak for all of them. I'm pretty sure they are hesitant to recommend foam for fear someone will use the Great Stuff for gaps and cracks that comes in the red can which will bow the frames out.

Since we are in the window and door installation business, we use a lot of foam, so we use a pro gun, which makes the foam easy to dispense. It works best for gaps that are > 1/2" wide. If the gaps get smaller than that, we'll use DAP Latex foam, which has a small straw. The cans are kind of a pain, but they insulate well.

A friend of mine who owns an insulation business also swears by these same methods.
 
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Old 03-27-08, 03:33 AM
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I agree with Xsleeper on the foam. Fiberglas will lose it's insulation ability if it is compressed. The low expansion foam will have air bubbles in it when it cures to provide a little better insulation quality, as well as sealing up all the holes and cracks.
 
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Old 03-27-08, 04:08 AM
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Or DAP foam. It never fully hardens, but fills air gaps as well as non-expanding foam. Never use expanding foam, it can push out the frames of doors windows making the hard or impossible to open.
 
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Old 03-28-08, 09:47 PM
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Today, for the first time in over 10 years of window and door installs, I purchased a can of Dow Great Stuff window and door insulating foam. The first thing i noticed is price. It cost roughly eight dollars at Home Depot and does 4 windows. A roll of R-11 costs maybe $15.00 and does probably 10 times the amount of windows. I installed my customers entry door and after shimming and screwing everything in place I used my spray foam around the new unit. The second thing I noticed is that it takes a while to fill my cavity 50% full as the can instructions dictated. Probably 2-3 times longer than if I used fiberglass insulation. It may not be a big deal when doing just a single door install, but on a job with multiple windows(we just did 28 double hungs last saturday, and have 24 to do on Monday) I can imagine it adding unnecessary hours to a job. I'll admit this could be just my inexperience with the stuff. Then I waited a few minutes to see. It still expanded quite a bit, but stayed soft for the duration of the time I was at this jobsite. However it's extremely messy and sticky. Also as it expanded it decided it would expand right through the hole in the jamb for the deadbolt and got on the brand new hardware. Extra cleaning, Argh. I should have gone with the latex brand.

I also know that fiberglass loses its insulation ability if it's compressed, as Chandler pointed out, but that's why when using it we use just the right amount so as not to render it ineffective.


What happens when you have to remove that door/window to repair or replace it? I've removed units with this foam around it and it's not a picnic. Or what about your voids where the window weights were? Are you going to fill it with foam as well? If that's the case that only compounds your time/material cost. Now think about the amount of empty aerosol cans that are going where? Do you recycle these?I'm guessing alot end up in the landfill. So, considering all these factors, the biggest being cost, I have to say thumbs down on spray in foam.

Maybe I'll try the Dap Latex sometime, but I think I would need to hear some better arguments for it to get me to change my mind.


Thanks for your replies
 
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Old 03-29-08, 05:30 AM
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I can't justify everything you mentioned, (and don't need to- everyone has the right to make their own decision) but our window company will gladly foot the extra cost of the foam in order to do a better job of insulating, stopping of air leaks, which results in happier customers who don't feel a draft coming around their trim in the dead of winter.

We use the bigger 22 oz cans which seem to last a good long time. They probably will do a dozen average sized windows- a lot depends on how much you use. We don't fill the entire rough opening with foam. A couple times a long time ago, we purchased a 2? gallon can with a hose and ball-valve type dispenser, which I wasn't impressed with. It lasted longer and was probably more cost-effective, but I didn't like anything else about it.

As far as the time is concerned, DAP latex comes out of the can more slowly (esp if the cans are cold) which is why I only use it for smaller gaps that my pro gun won't fit into- the ones that are 1/2" wide and smaller. The pro gun along with the larger can speeds things up tremendously. I almost never have to use any cleaner, never make a mess with the gun, can control how much I dispense with a trigger... it's just a better system than the silly little DIY cans with the plastic straw and trigger. Of course if you were just "trying" the foam you probably didn't spend $50 on a gun which is understandable. But with the gun, it takes maybe 30-60 seconds to foam the average window perimeter- much faster than I could stuff fiberglass, which I also did for years, and still sometimes will occasionally do. Once you get onto the technique of foaming, you spray the foam far enough back into the RO that it doesn't expand out too far and make a mess- although sometimes some does come out, which you can usually leave until it sets up, then cut it off.

As far as insulating weight cavities goes, I would *NEVER* recommend using expanding foam inside a weight cavity. And I hope that if someone searched the forums here that I have never recommended it in the past. Weight cavities are usually about 1 1/2-2" wide, and while one "could" foam them, it would certainly use a lot of foam and take a lot of time. Insulating weight cavities is a pain in the rear end and fiberglass does work better in that situation. It doesn't stop all the air, but IMO, if they wanted a better installation with no under-insulated air spaces around the perimeter of the jamb, they shouldn't be using a retrofit window- they should be using a new construction style window and replacing the entire frame so that the installers can do a decent job of air sealing the new window. That's just how I look at it.

If you do try the Dap Latex, you will be even less impressed by the cost and the speed factor. With either product, it helps to have the cans hot- such as by sitting them in the windshield of the truck, on a heat register, or I've even warmed some in the oven during the winter months. They can be a pain that way. You're right about the landfill, but if the cans are quite warm when you use them, they usually dispense faster and more fully, leaving less waste in the can.
 
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Old 03-29-08, 10:35 PM
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XSLeeper

Let me just say to begin with, I respect your opinion and am pleased that you would take the time to put it out there. Countless number of people, myself included, have benefitted from your knowledge in this area. But I still have questions from your posts.

I can only guess that you are doing more new construction windows than replacement. I think that in a new construction environment, where your gap can be 1/2" or more, spray foam with a professional setup would be ideal, and far superior form of insulation. However, when dealing with a replacement window, the intention is to reuse the existing stops which are rarely over 3/8" inch thick. If your gap between old frame and new unit is 1/2" your stops would not cover your window, and would leave an unsightly gap that would need a nice thick bead of caulk or an additional trim piece to cover. This would eliminate your professional setup and resort us back to the small strawed Dap foam.

I guess i'll just say that I like my tea with lemon.
Whatever that means.
 
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Old 03-30-08, 06:04 AM
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I use Great stuff low-expansion foam on a daily basis for the past 5 years and now dread dragging a bag of fiberglass through a customers house. Hilti makes some good foam too but it is quite a bit more costly. Although they make more accessories for smaller gaps and hard to reach places ,most of them will fit on the cheaper Pro -Series gun. The cans are interchangeable too. Pella even went as far as to hook up with Great Stuff to formulate a foam ideal for window and door applications and has their logo on the can that they supply to their installers.
 
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Old 03-30-08, 08:29 PM
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Grob, there's many ways of doing it, no one way is necessarily the "right way" since as they say, there's more than 1 way to skin a cat (who skins cats anyway?) The windows we do are probably 50% total tearout (new construction style replacement) and 50% retrofit into the existing frame. When installing retrofit windows, we usually only deduct 1/4" from the height and width of the opening which would result in roughly an 1/8" gap on all sides of the window if it was perfectly centered in the opening. Our windows come pre-wrapped with open cell foam tape, we do not tuck any fiberglass into the resulting 1/8" gap (except maybe under the sills), and we most often will caulk the interior perimeter prior to the installation of the interior stop. So I guess most of the advice I mentioned in the earilier posts applies mainly to the total tearout (new construction) method, not to retrofit. Sorry if I missed the point of your question.

One other thing I failed to mention earlier, when you asked about the difficulty of tearing out a window or door that has been foamed... it's really not hard to do at all, since running a reciprocating saw or a drywall (keyhole) saw around the door or window easily cuts the cured foam, and the window or door can then be pulled free.
 
 

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