Insulation, Fact or Fiction??


Old 12-23-02, 08:35 PM
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Insulation, Fact or Fiction??

I was recently discussing insulation with a friend and he was telling me heard of this new stuff that is now used. He compared it to Rhino coating for the inside of pickup truck beds. He said they spray it on and it seals any cracks and air leaks and then it slightly expands then gets very hard. He said in addition to that they spray in an expanding foam behind the drywall which fills the entire space behind the drywall. (On a sidenote he said the expanding foam is a bit tricky as if too much is sprayed in it can push your drywall off the wall.)

So, does this sound valid? I agree the expanding foam would probably be a good thing to a point, as long as you don't ever decide to run and cables or wiring of any kind after this is done.
I don't know too much about the hows and whys of insulation and which is better and all that stuff. My question is, would this stuff work as both a vapor barrier and insulation? I would certainly expect this to be a good soundproofing as well.

One other quick question, which is better for for better energy efficiency in a home, plaster or drywall? I know plaster is a pain if you ever wanted to hang a poster since thumb tacks just bend and it doesn't seem as easy to repair. (IM0) Is it more sound proof than drywall?
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Old 12-23-02, 08:42 PM
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I can't comment on the first 2, haven't heard of either one.

Plaster vs drywall. I've lived in one house that had plaster, and I loved it. The stuff is basically concrete, very sound insulating, takes screws for hanging (without needing inserts). I suppose it might be difficult to repair, but probably no worse than drywall.
You don't want to brush up against it though, as it does a fine job at removing skin.

My overall preference for wall material though is 7 ply 3/4" marine grade plywood. It's expensive for wall covering, but damn is it solid as a rock, does a fantastic job of sound blocking and takes nails or screws without a hassle and is easy to smear some putty over the hole and paint it when you're done.
Old 12-23-02, 09:18 PM
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Ouch you must have textured plaster. I have that on my ceillings but not my walls. I think there is a commercial about that where the entire family scrapes up against it and are all cut up and stuff. I don't remember what it was for but it was funny. You may find it hilarious since you can relate. The last place I lived in had textured walls and the next person who lived there actually wallpapered over the textured paint. It was very interesting as you could see the bumps under the wallpaper. Some people do goofy things. Glad that was only a rental home!
Old 12-24-02, 03:50 AM
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Expanding Foam.
Yep, even seen them use it on This Old House.
That was new construction(an addition), they applied it before the drywall went up. I suppose it could push out drywall if injected. Not exactly Rhino lining!
You can buy a can for small holes, etc. Called- Great Stuff.

Old 12-27-02, 08:47 PM
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I've actually seen them use the foam in person. The spray it on like 1/4" thick and it actually expands past the stud cavity. Then they trim off the excess with a long electric knife.
Old 12-28-02, 08:30 PM
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So this expanding foam... would this be the way to go or the pink stuff? I have been reading many of the previous posts in this forum and they talk about vapor barrier and radiant barrier. Does this expanding foam do the job to prevent condensation, mold and whatever else proper insulation should do? Kind of an all in one solution?

On a side note I have used the Great Stuff in the can for a few things such as around holes the were cut for pipe and cable going outside and under the bottom peice of vynil siding. For the project I'm going to take on I would sure need alot of cans of Great Stuff!
Old 12-29-02, 07:30 AM
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From talking to the guy who was spraying it in. It is the way to go if you have the money. He didn't give me a price comparison though.

As said before, it fills in all cracks, holes and what not. You can assume that since no air(moisture in air) will pass the foam that it might act as a vapor barrier. I'd put the vapor barrier in just for cheap insurance.

While this guy was spraying this foam I was running wire for a security system. It's very stiff but it is penetrable. It would be very difficult to fish any type of wires through an existing wall filled with foam. So you must have good planning.

If I remember correctly they had a big hopper in a van that held the foam and just shot it through a hose on to the walls.
Old 12-30-02, 08:18 PM
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Hmmm.... I guess since I am currently laid up right now I have some time to shop around and compare prices. Once I'm back to 80% (I haven't been a 100% since my 20's so 80% is good enough) I'll start ripping down plaster. I'm only going to do one room at a time so I can spread the cost out over several months. It really sounds like the stuff to use though. Thanks everyone for your help!
Old 12-30-02, 08:30 PM
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Expanding foam insulation in Canada still leaves a bad taste in peoples mouths, because of the promotion of Urea Formaldehyde Insulation (UFI) by our government in the seventies.

They subsidized its installation until it was found to be a health hazzard due to off-gassing of formaldahyde fumes.
Other problems were a lack of quality control in its installation. Many homes that were retrofitted had major gaps in the insulation that homeowners were not aware of.
The insulation was also subject to deteriation when wet and was responsible for bulged walls if not installed properly.

What's being used today might be better but I think conventional construction is safer.................especially considering what it would cost if a mistake were to be made.
Old 12-30-02, 10:42 PM
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Yikes! I can't say I'm any less confused on what to use now. =)
Back to square one. That's okay I have time!
Old 12-30-02, 11:03 PM
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foam insulation


I have been researching this stuff for months, and found out no one can testify about the actual validity, except the manufacturers. And they all say that theirs is the best, and the others suck.

Heres what I found out, in a nutshell.

For new construction, the sprayed in place is great. After it expands, they cut off the over-expanded foam with a hand saw between the studs, and drywall over it.

For existing wall cavities, you must use a "puorable" type, with limited expansion. They measure the void, calculate the expansion, and determine the amount required for each void.

Now for the pros and cons,

The cost for new construction is estimated at 4+ times that of batt insulation.

Moisture problems. There are two types, open celled and closed cell. Most foams are closed cell, and they do not allow the transfere of moisture. Trapped moisture causes mold and mildew in the walls, and that causes sickness.

There is one company in Canada that makes an open celled product, and it looks neat. Cant remember the name, but they are on the web.

As in most things I want to try or play with, I had no luck in aquiring any of this foam, so I tried the stuff in a can at your local Home Depot. So what if the warning on the can says not to spray it into wall cavities, I know what I'm doing.

30 minutes later, "BANG", the sheetrock explodes. It was scary, but not as bad as the look on my wifes face.

I did find a site where you can purchase the foam and applicators,

Good luck, and don't spray it in closed areas with the wife around.

Old 01-02-03, 10:23 PM
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I have used foam product quite a bit over the years, inspected both new construction (quick expansion) blown-in and old construction (slow expansion). Over the years I have been asked literally thousands of questions concerning foam insulation, including UFFI. What makes foam insulation unique to me is that on several occassions I have asked questions to manufacturers and contractors of this insulation. The best reply so far was, "They'll get back to me." Which they never did.

Considering some people have done some research on this product, I figured let me ask the question again. Perhaps someone can answer it for me, so I can pass it on to others who might ask me the question. My question is:

What happens to foam insulation when exposed to fire or temperatures over 1000 degrees F.?

I am really interested in the chemicals used in these products that increase the flash points and melting points of these products. I am not aware of any chemicals used in foam to do this. My concern is, are these chemicals, if they do exist, hazardous to the occupants of the home?

I would really appreciate any information on this subject, so I can pass it on to others when asked.
Old 01-03-03, 08:51 AM
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Glad to see I'm not the only skeptic out there.

There is an amazing number of products and ideas being sold based on bad science, misinformation, twisted facts and belief based ideas.

Here is some info I have on foam insulation and fires.

Don't see anything specific on chemicals that raise flash points.
I'm sure they are as healthy as the chemicals that make cigarettes burn sooo smooth.
Old 01-06-03, 08:16 PM
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I have been doing some research myself. I found one site and I can't remember the address but they talked about all the various types of insulation. There was extensive information about the foam. On that site it talked about the good and the bad of this insulation. In a nutshell it said that as far as being a fire hazard it is only a fire hazard if it is left exposed. Such as in a place like a warehouse or pole building where it is sprayed on and no drywall or plaster is added to cover it. If it is exposed to oxygen and the fire gets hot enough it will burn. Not only will it burn but it will make the fire 6 times hotter than it would have been without it. It can also make the fire accelerate very rapidly and severely cut down on escape time. They say that if it is in between walls it will not have this effect. At this point I do not know what to think. All I do know is that I have a drafty and cold home and I need something that will seal the cracks/holes and not just cover them up. If I'm going to go through all this work I would like it to be as effective as possible, I'm not worried about the extra expense of doing it right. If anyone else finds any more useful information on this please keep the thread going. Thanks!

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