A while back I asked the group for information about insulation. We are building a house/cabin. We were delayed because of contractors, retirement , etc. Anyway, the house is ready for this next step and any knowledge would be welcome. I do think we will be going with foam but other than that I am open to suggestions. Thanks in advance.


Jim

Foam is good.

However, without these things it can have voids or be badly mixed so ineffective:

The tanks need to be the correct temperature, meaning electrically heated for at least 24hrs prior to spraying.

They test the mix periodically.

The surfaces to be sprayed need to be above 40, so heating the space in winter is necessary to stop the foam from bouncing and creating voids.

A blower door, smoke sticks, and infrared camera to check for voids is key.

You don't just show up, spray foam, and leave.

The foam company, and contractor, will do thses things if they have experience.

Thanks for the reply Arc. A blower door test is required here, and the contractors I talked to have said they chalk and other things prior to the foam. What about closed cell vs. open cell?

Arc, what is your opinion on pests and spray foam insulation?

I was told by a contractor that the house would need to be better sealed before attempting foam, because if a mouse gets in they can tunnel through the foam easier than anything else and it will be magnitudes more difficult to try and get them if they start to tunnel that way.

I'd love to spray my attic and add-on crawlspace, but this has put a hold on that.

Closed cell in basement spaces for sure. I've done a few all closed jobs, where it is sprayed throughout the home. It is superior to open cell, but you better plan your utilities. Closed cell is unforgiving for changing or adding utilities. Open cell should not go below grade, but performs well elsewhere.

Overall R value is half the story for the success of spray foam. Its air sealing ability is key. Insulation without air sealing is not only less effective, it is the cause of ice dams, mold, and many moisture related problems in a home.

The foam sprayed now is waaaaay better as far as environmental impact, and danger to installers. As far as occupants, it is safe and basically inert after 24hrs.

As far as pests in spray foam, we evaluate and mechanically seal first. I can also tell you that any vermin in the home will flee due to the activity and the foam itself, after which you close off where they got out.

An infrared camera is great for finding access points of pests, regardless of the presence of insulation or its type.

Pal,

I see you're in Michigan. I highly recommend this company. I've used them twice and plan to use them a third time as well in the future. First time they did the foam injection into holes from outside the house, Second time they did the spray foam in our new basement. Hope to have them do a pole barn for us in the future.

They did open cell in our basement as it is fairly new construction and didn't have any water issues. From their website this is what their reasoning is:

Open Cell vs Closed Cell Spray Foam Insulation for the Basement

Many contractors will say to use open cell spray foam above grade and closed cell spray foam below grade – which means above and below the ground level. The reason for this recommendation is that some contractors believe that because closed cell spray foam is an absolute vapor barrier, doesn’t let moisture move through it, and is resistant to bulk water. In Michigan’s climate zone, we can be more prone to moisture issues and that’s why contractors will suggest closed cell spray foam. An experienced contractor won’t recommend closed cell spray foam to fix any moisture problems in the basement. It’s better to address that problem than to put a layer of closed cell foam on top of it in hopes of fixing. Both closed and open cell foam will provide the needed air seal at an application of 2-inches and 3-inches, respectively. Most homeowners are unaware that open cell spray foam insulation won’t absorb water, so if the basement leaks it will show the homeowner where the leak is so it can be fixed before causing further damage. Because of this and open cell foam’s superior sound dampening abilities, more and more homeowners are choosing open cell spray foam to insulate their basement.

One argument for closed cell that I have heard is that it actually makes the home stronger because it becomes solid. Is this true? I do understand why this could be valid but I don't know. I do know that, around here anyway, that closed cell is more expensive. And Arc, my son is an electrician and he has mentioned more than once that I better have my electrical ducks in a row. The companies I have talked to have said they do the mechanical sealing. I also wonder about mice, I can see how they could tunnel in open cell but the closed cell not so much. Am I missing something? Thanks,

Jim

I did check out the company mentioned, I'm sure I will be talking to them as well.

Jim

quote:

Originally posted by Pal:
One argument for closed cell that I have heard is that it actually makes the home stronger because it becomes solid. Is this true? I do understand why this could be valid but I don't know. I do know that, around here anyway, that closed cell is more expensive. And Arc, my son is an electrician and he has mentioned more than once that I better have my electrical ducks in a row. The companies I have talked to have said they do the mechanical sealing. I also wonder about mice, I can see how they could tunnel in open cell but the closed cell not so much. Am I missing something? Thanks,

Jim

Pal-
Much of what Arc has said is correct. To answer your question about making the wall stronger that is correct to a degree. Hopefully your home is already framed well.

Self Promotion Ahead ----

Our company builds some of the most energy efficient home in the state of VA and have won many awards for our clients, many of whom are engineers etc. Anyway, a year ago the insulation manufacturers association contacted me to see about making a video for contractors to meet the upcoming more stringent codes which we are already doing.

Here's the video.. (Dam it was about 90+ degrees that day)

https://www.youtube.com/watch?...XzI&feature=youtu.be

Our preferred method of wall insulation is to use a process called "Flash & Batt" which involves spraying approximately 1/2" of closed cell foam and the filling the cavity with batt insulation. Keep in mind that open cell foam does not insulate any better than fiberglass insulation and if the insulation is installed properly (Grade 1) it is much more cost effective.

Let me know if you have any specific questions.

Closed cell foam isn't a solution to a wet basement. If there are water problems they need to be dealt with first.

Having dealt with a variety of conditions, in homes ranging from years to centuries old, and using either closed cell or foil faced polyiso, I'm confident it's not foolhardy.

Open cell foam holds water, and can obfuscate leaking. I wouldn't put it, cellulose, or fiberglass in a basement. Roxul I am comfortable using in a basement. If there is a chance of active leaking, I would deal with that proactively rather than use open cell below grade.

Foam insulation doesn't deaden sound. Air sealing does. Fiberglass can, Roxul can. But the main difference in sound is due to the air sealing and typically better doors and windows that come with it. If you want real sound control, it has to be built in.

"Flash and batt" is a reliable method. There I prefer roxul over fiberglass as well. I'd use it in this application, except in a basement.

As far as fiberglass being the same as open cell, the R value on paper is similar yes. Why fiberglass is not as good, boils down to its installation. Spray foam will have much better coverage and more complete air sealing than all but the most dilligent fiberglass install. And then it will probably still do better on the blower door.

In my own home, I've thickened walls to allow for closed cell or polyiso on the exterior 3.5," with 3.5" Roxul inboard of that so I can have normal utility freedom.

If a builder will warantee something and actaully come back years later should a problem arise, I won't quibble too much with their methods.

Rats can get through closed cell, most everything else either can't or stops trying. Once a home is well insulated, it becomes less likely rodents will find shelter, as the primary way they are drawn in is a spot of warm air beckoning.

If a company applies foam through holes from inside or out, as long as they use infrared to find voids and areas blocked by framing, it's fine. Same for dense pack. I've dense packed back plaster with success.