Importance of Foam Insulation

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AliInBaltimore
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Importance of Foam Insulation

#1 Post by AliInBaltimore »

How important is the use of foam (versus say standard fiberglass) to insulate/seal the gaps during window installation? Everything else being equal (skilled installers, OKNA windows, etc), will a foam install always provide a better barrier against air penetration? Is the difference enough, in your opinions, to be worth a couple thousands of dollars (for say a 15 window replacement)?

I appreciate all of you taking the time out to share your experiences.

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Windows on Washington
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Re: Importance of Foam Insulation

#2 Post by Windows on Washington »

It definitely is a difference maker. No open is ever quite square and the best air and water seal is closed cell foam.

Not sure it is worth a couple of thousand bucks but it might demonstrate a bit more attention to detail out of install company A vs. company B that could translate on other items.

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TheWindowNerd
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Re: Importance of Foam Insulation

#3 Post by TheWindowNerd »

Definitely agree that window foam is the best way to go. It does show a different level of care.
But a window sealed properly with fiberglass will probably be just as good.
Not sure if it justifies the premium that you are being charged.

AliInBaltimore
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Re: Importance of Foam Insulation

#4 Post by AliInBaltimore »

It is my understanding that foam-installed windows are made a bit smaller than windows that are not foam insulated/sealed. Is that correct?

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HomeSealed
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Re: Importance of Foam Insulation

#5 Post by HomeSealed »

Like the other guys mentioned:
1) yes, foam is decisively superior to fg. Caulk can also be used effectively in areas where foam does not fit. Same idea.
2) No foam is not worth thousands more on its own, that said, as the other guys alluded to it is often indicative of the level of quality and knowledge that you may expect from a company/installer.

Lastly, no, windows are generally not measured smaller for foam. Windows are measured to fit the openings that they are to be installed in. Those openings are often not square, whereas the new window needs to be square, so some gap results after that cutback. Caulking in the tight spots and foam in the larger spots (if not one or the other depending on how it fits) is best practice.

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Randy
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Re: Importance of Foam Insulation

#6 Post by Randy »

Foam insulation can be applied in a smaller gap than fiberglass insulation. Closed cell polyurethane foam is a certified air and vapor barrier, fiberglass is neither.

Window4U (IL)
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Re: Importance of Foam Insulation

#7 Post by Window4U (IL) »

While using foam is superior methodology, some old-time installers are set in their ways and are very stubborn; for some reason they like to stay with what they know even if it costs them business. I would think that if a customer insisted that window foam be used on their job that any installer would be smart enough to go buy a $30 foam gun and use it, especially if it means the difference between getting a 15 window job or not getting it. I just can't figure out why these guys would stand there arguing.... for god's sake, do what makes your customer feel comfortable!

:idea: :idea: :idea:

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toddinmn
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Re: Importance of Foam Insulation

#8 Post by toddinmn »

Does the contractors pricing include filling window weight cavities with foam?? That is the only way I can see the pricing justified.

AliInBaltimore
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Re: Importance of Foam Insulation

#9 Post by AliInBaltimore »

What are "weight cavities"? I haven't heard this term before.

The contractor is willing to use foam -- and they have with persistent customers -- but their installers are in the business 18+ years and are thus more comfortable with fiberglass. However, in the case of foam, the contractor insists the windows should be made a little bit smaller so the foam has room to expand.

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Windows on Washington
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Re: Importance of Foam Insulation

#10 Post by Windows on Washington »

AliInBaltimore wrote:What are "weight cavities"? I haven't heard this term before.

The contractor is willing to use foam -- and they have with persistent customers -- but their installers are in the business 18+ years and are thus more comfortable with fiberglass. However, in the case of foam, the contractor insists the windows should be made a little bit smaller so the foam has room to expand.
How old are the windows that they are taking out?

Weight boxes are part of the balance system on older rope/chain and pulley systems.

Window4U (IL)
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Re: Importance of Foam Insulation

#11 Post by Window4U (IL) »

AliInBaltimore wrote:
-- but their installers are in the business 18+ years and are thus more comfortable with fiberglass.

This struck me funny for some reason. I gave up fiberglass and started insulating with Hilti brand foam in 1997, ...18 years ago.

AliInBaltimore
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Re: Importance of Foam Insulation

#12 Post by AliInBaltimore »

Windows on Washington wrote: How old are the windows that they are taking out?
The original windows for a house built in the mid 1980s.

AliInBaltimore
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Re: Importance of Foam Insulation

#13 Post by AliInBaltimore »

Window4U (IL) wrote:
AliInBaltimore wrote:
-- but their installers are in the business 18+ years and are thus more comfortable with fiberglass.

This struck me funny for some reason. I gave up fiberglass and started insulating with Hilti brand foam in 1997, ...18 years ago.
Well, they never specifically said that's the reason, but I feel it was strongly implied from our conversations. Also, they never specifically stated that fiberglass insulation was as good as foam, but that was also implied. The reason they wanted to make a bit smaller windows for foam-sealed installs: Insulation needs air space to do its job (that's why you shouldn't compress fiberglass insulation). Foam in small 1/4" cavities wouldn't allow for sufficient "breathability"; i.e., it would be like compressing fiberglass insulation.

Of course, I could have misinterpreted some of what was discussed, that's why I'm trying to develop some intuition on the matter before continuing discussions.

Delaware Mike
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Re: Importance of Foam Insulation

#14 Post by Delaware Mike »

I'd estimate that over 90% of all vinyl replacement window master frames have an offset of the face to the jamb depth to accommodate last ditch efforts in the field to trim the window in case of a tightly measured or too big of window/mis-measure. We see accessory grooves on most windows for mulling practices and other accessories. With that being said, the gap from the window to the jambs, head, and sill are a little larger than one sees from from a face forward view of the window.

If one were to deduct the standard 1/4" in width and height to the wood opening, the gaps or reveals on the new replacement window to the opening are never evenly spaced due to out square and out of level openings. Most experienced window pros that have embraced modern best building practices realize that a couple of high quality foam dispensing guns with reducer tips allow for spray foam to be penetrated into the smallest of spaces. It's so much faster than messing with fiberglass and less coughing and gagging, much safer for the mechanic.

I personally don't change my make sizing manufacturing for using foam verses fiberglass as I don't want the interior accessory groove to be potentially not 100% hidden behind the colonial stops (provided it's a traditional wood tear out). My helpers get mad at me when I don't let them work the foam gun as they find it cool, well that is until they change a can off the gun and it goes haywire on them and wrecks their clothing.

When you're stuffing fiberglass around a tightly measured insert window you're not really insulating more than you're draft blocking. That quote comes directly from a Bob Vila episode many years ago when he got embarrassed by a window pro.

masterext
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Re: Importance of Foam Insulation

#15 Post by masterext »

AliInBaltimore wrote:
Windows on Washington wrote: How old are the windows that they are taking out?
The original windows for a house built in the mid 1980s.
No way do you have weight pockets in a home built in the mid 80's.

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