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mcamm
Q&A Forums Registered User
Posted: 4/03/2012 1:35 PM EST

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spray foam in crawl space?
Hello. I am new to this site and forums so I am hope I am posting this question in the correct forum.

i recently had a inspection on a home I am purchasing in the Boston area. The home was built in the 1950's and is a ranch style home. Rather than have a basement it has a crawl space under it, The crawl space has an open dirt floor that they has covered with plastic sheeting sitting on top of the dirt floor. There has also a fiberglass type insulation added around the perimeter of the of the wall where the wall meets the bottom of the main floor,

There is some white mold in a few spots that are under the bathrooms (probably from some shower leakage in the past) that the home inspector told me about.

The crawl space is a bit damp and humid.

I was told I have two choices to address this.

1) is to pour a concrete floor as well as install a sump pump. They mentioned something called Neutocrete?

2) Spray foam the ceiling of the crawl space using a company that describes their spray foam as follows: ( I am not sure if the forum rules allow me to post the URL of the company so I have cut and pasted their description and removed the brand name of their spray foam.)

Foam is a spray-in-place, medium density, two-part, soy based polyurethane foam insulation. It is a 2 lb. Closed Cell and 1/2 pound open-cell, rigid foam that in one step provides a sealed, thermal envelope that simplifies construction practices. It is rated by the Canadian National and Alberta Building Code as an approved Vapor Barrier, Air Barrier, and Thermal Insulation. The Foam exclusively uses materials which have been certified and formulated with the Environment in mind. It is made from Soy Bean Oil, Sugar and Recycled Plastic Bottles. It emits no VOCs (Volatile Organic Compounds) or CFCs (Chloro-Fluoro Carbons). It contains no formaldehyde or bleach. It behaves just like petroleum based spray foams, without any of the harmful Environmental side effects. The Foam is the most cost effective, energy efficient and Environmentally friendly insulation method available today.

The Foam is made from Soy Bean Oil, Sugar Cane, Recycled Plastic Bottles, and Resins. It is a two component liquid system that is spray applied like paint, using a Zero Ozone Depletion Substance (Zero ODS) blowing agent.

The Foam has the highest R-Value (7 per inch) of any insulation product available today

So, my question is what do you think of the spray foam described above and do you think this is the correct approach vs pouring a concrete (newtocrete?) and installing a sump pump?

The contractor said that installing the foam will solve the humidity problem and get rid of any future mold issues.

I am interested in your opinion as I don't have any experience with this and want to make sure I am making the right decision and not damaging the home I am about to purchase.

Thanks in advance for your help!

Mason  

Moderator
Posted: 4/03/2012 2:19 PM EST

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RE: spray foam in crawl space?
Sprayfoam can be installed to the ceiling of the crawl space and then vented to the outside, or you can install it to the walls of the crawl space connected to the plastic covering the floor and have an unvented space. If there is a high water table then a sump pump may be needed as well. I am on the road right now and don't have access to my files but go to buildingscience.com and read the articles about basements and crawl spaces. Lotsa good info and descriptions on how to use sprayfoam in those areas.

mcamm
Q&A Forums Registered User
Posted: 4/03/2012 2:27 PM EST

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RE: spray foam in crawl space?
thanks for your speedy reply! I am not sure what you mean by "vented to the outside".

I will look at the articles at buildingscience.com. I am also VERY interested in your thoughts on the foam this company uses - I posted the details of it in the message above.

when you get back to your office and have a moment please get back to me,

Thanks!

NHsprayfoam.com  

Q&A Forums Registered User
Posted: 4/05/2012 8:01 AM EST

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RE: spray foam in crawl space?
Hi Mcamm,

Regarding the foam description, there are a couple of items that jump out at me.

"It is a 2 lb. Closed Cell and 1/2 pound open-cell, rigid foam that in one step provides a sealed, thermal envelope that simplifies construction practices. It is rated by the Canadian National and Alberta Building Code as an approved Vapor Barrier, Air Barrier, and Thermal Insulation"

They are talking about 2 different products here yet they lump them together as one. Both products are air barriers and provide thermal insulation. Neither product is a vapor barrier as that would mean zero vapor passes through it. Closed cell foam is a vapor retarder which means that a very small amount of vapor is allowed to pass through it. Closed cell foam is definately the product that you want to use in your application.

"It is made from Soy Bean Oil, Sugar and Recycled Plastic Bottles"

This is just marketing BS. Although there are some of the ingredients in the foam that can be derived from those items, it is a very small part of the foam. Typically less than 15% of the B side of the foam system can come from soy and such.

"It behaves just like petroleum based spray foams, without any of the harmful Environmental side effects."

More BS. Almost all spray foams on the market contain some amount of sugar based polyol and some recycled PET content. All spray foams use polymeric MDI as the A component of the foam and all use similar fire retardants and have 245fa as the blowing agent on the B side. All spray foams have safety concerns for the applicator during application. The homeowners should not be home during application of any spray foam. The area of application should be vented during and after application of any spray foam.

"The Foam has the highest R-Value (7 per inch) of any insulation product available today"

This is close to true if you round the numbers. I have looked at alot of spec sheets for closed cell foams and I have see R-values of 5.9-7.4 per inch. There are different ways to report R-value. The first is the result of testing a 1 inch thick sample of foam. This gives you the R-value at 1". Then you test a 3.5" sample and take that R-value and divide it by 3.5 to get the R-value per inch at thickness. You need to look at the icc report to see what the R-value at your installed thickness will be. Not that it matters much, an R or 2 in a crawlspace, but it is the principal of the way things are presented to you. The company that advetises R-value of 7.4 at 1 inch has an R-value of 6.6 per inch when you go thicker.

Hope this helps. Whatever you decide, make sure that the applicator has had the proper training. Good luck. Sorry to hijack your thread Mason!

George

mcamm

Q&A Forums Registered User
Posted: 4/05/2012 9:03 AM EST

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RE: spray foam in crawl space?
George,

Thank you VERY much for taking the time to respond. I can't tell you how much I appreciate it.

Is it common practice to lump two products together (closed cell and open cell)? Is there some sort of advantage to doing that or is that more BS as you indicated for some of their other claims below?

Do you have any opinion or guidance on if the spray foam is the way to go to solve the problem? Also, do you know what this cement option is called Newtocrete? If so any opinion on that approach?

Mason and George. Thanks for your time. I really appreciate your input.

airpro  

Q&A Forums Registered User
Posted: 4/05/2012 10:52 AM EST

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RE: spray foam in crawl space?
I agree with George.

Sounds like someone over-selling their product and ether over-pricing it or selling a substandard product that doesn’t have proper testing.

And this is what makes me mad, for the most part spray polyurethane foam is spray polyurethane foam and spray polyurethane foam is the best insulation there is regardless of the manufacture as long as that manufacture is big enough to pay for proper testing and doesn’t have lie to sell it.

I will say that I have sprayed different brands and a good sprayer can get good results with almost any brand of foam, some are easier to work with, some are a little cheaper, and some have higher yields.

The bottom line is find a contractor that you feel that you can trust and uses a good product that has all the proper testing for the application.

Airpro

Ps; I have not heard of Newtocrete

mcamm

Q&A Forums Registered User
Posted: 4/05/2012 4:40 PM EST

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RE: spray foam in crawl space?
Airpro,

Thanks for your response! I appreciate it Any thoughts on if spray foam is the way to go on the roof of the crawl space to address the problem?

NHsprayfoam.com  

Q&A Forums Registered User
Posted: 4/05/2012 6:18 PM EST

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RE: spray foam in crawl space?
I think that the content describing the foams should have been done differently. I am not sure why they lumped the 2 products together. Just sounds like the text is not written well.
Closed cell spray foam is definately the way to go. I have not heard of neutocrete, but it sounds like a lightweight concrete that can be pumped in from the outside. That might be ok over the plastic, but not on the walls.

Spraying foam to the underside of the floor will not do anything to control the humidity in the crawlspace unless you are going to vent the crawlspace to the outside. Is there a heat source in the crawl space? What about plumbing? If yes to either question, then I would make sure that all the bathroom vents are vented properly to the outside. If the plastic on the floor is in good shape, leave it, if it is ripped or damaged, replace it and try to run it up the wall a little. Remove the fiberglass and throw it away. Be careful of the mice that like to nest in it and make sure you were gloves, coveralls and a mask, it is itchy! Then spray foam the walls down to the plastic and create a conditioned crawlspace.

George

foamdude

Q&A Forums Registered User
Posted: 4/05/2012 8:34 PM EST

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RE: spray foam in crawl space?
i look at most crawl spaces as "pygmy basements",,,
basements with short sidewalls...so should you..
conditioned space,,pure and simple..end of system problems for the rest of the structure..

we lay out a slab on grade of closed cell foam at a depth of 2-3" continueing up the sidewall and to the box sill and rim joists assemblies...
even better if you can cement pour the floor over the foam..yeah right..but we done that in tallboys too(best system imfuo)
nope nothing in the subfloor as the pygmy basement is now conditioned...

mcamm

Q&A Forums Registered User
Posted: 4/06/2012 9:24 AM EST

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RE: spray foam in crawl space?
NHsprayfoam,

The only venting in the crawl space are some vents in the cinderblock. Is that what you mean by vents?

There is no heat source in the crawl space. The plumbing pipes are in the crawl space.

So I would spray foam down the floor ceiling of the crawlspace and down the wall to the dirt floor, right?

NHsprayfoam.com  

Q&A Forums Registered User
Posted: 4/12/2012 12:18 PM EST

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RE: spray foam in crawl space?
Hi Mcamm,

Yes, venting that lets outside air into the crawlspace. With no heat in the crawl and the plumbing down there, do the pipes freeze, or do you have them heat taped? You have a couple of options, spray the walls and the floor of the crawlspace, or put heavy 6mil or thicker plastic on the floor of the crawl and up the walls about 8"-12" then spray foam down the walls to the plastic.

George

mcamm

Q&A Forums Registered User
Posted: 4/12/2012 12:45 PM EST

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RE: spray foam in crawl space?
There is 6mil plastic layer out over the dirt floor already. They do not have a problem with freezing pipes.

What they are telling me to do is the ceiling of the crawl space and then down the wall to the dirt floor (which is covered with plastic).

Make sense?

Mason  

Moderator
Posted: 4/13/2012 2:34 PM EST

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RE: spray foam in crawl space?
Not to me. You either spray the ceiling and vent the space or spray the walls and don't vent the space. I agree with George on the closed cell foam. In both cases leave the plastic on the ground.

fairfieldct
Q&A Forums Registered User
Posted: 6/04/2012 9:15 PM EST

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RE: spray foam in crawl space?
Mason, I have the same issue with my crawl space and a lot of the information provided is confusing me. If you could point me in the right direction I would appreciate it.

My house was built in 1942. I have 500 square feet of a dirt crawl space which is a little higher then my basement area which does have a concrete floor and a sump pump. I have no water issues on the crawlspace or the direct crawl space.

This is my plan.

I am going to redo the plastic barrier on the floor with a new 6 mil barrier and bring it all the way up the walls ( 4 foot wall in crawl space)

Then I am going to rent a concrete pump and have a couple trucks worth on concrete spread on the floor over the new 6 mil barrier.

Going to wait a couple days and then remove the fiberglass installation and then have someone spray foam (closed cell) the entire ceiling and down the walls until it meets the new concrete.

I have no source of air to the basement from outside. The door to the basement is in my garage and I have my water heater and furnace in the part of the basement which you can stand.

Does this sound like a good plan to you? Do I need to run the plastic up the side of the crawl space walls or can you spray closed cell right on the concrete walls with no barrier?

Expense is not much of the issue as making sure it is done right the first time so it never needs to be touched again.

Appreciate your time and response.

Adam

TJBoehs

Q&A Forums Registered User
Posted: 6/04/2012 10:41 PM EST

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RE: spray foam in crawl space?
I'm with George and Airpro all the way!!

foamdude

Q&A Forums Registered User
Posted: 6/05/2012 5:16 AM EST

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RE: spray foam in crawl space?
i look at most crawl spaces as "pygmy basements",,,
basements with short sidewalls...so should you..
conditioned space,,pure and simple..end of system problems for the rest of the structure..
and for the crawl space as well...
we lay out a slab on grade of closed cell foam at a depth of 2-3" continueing up the sidewall and to the box sill and rim joists assemblies...
even better if you can cement pour the floor over the foam..yeah right..but we done that in tallboys too(best system imfuo)
nope nothing in the subfloor assembly as the pygmy basement is now conditioned...
works well..and a guy can make a living spraying foam...

Mason  

Moderator
Posted: 6/05/2012 11:19 AM EST

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RE: spray foam in crawl space?
I agree with Foamdude's suggestion. It is similar to how we design freezers with spray foam. Only difference, the dirt floor typically holds a lot of moisture so laying down poly before the foam might be a good idea. You should not require poly on the walls if the foundation wall is correctly installed with drainage tile system and waterproofing or damp proofing on the outside walls. Cover with cement and let the air from the inhabited space infiltrate into the crawl space. This would work well. Much better than spraying the underside of the floor and not venting.

fairfieldct

Q&A Forums Registered User
Posted: 6/05/2012 11:06 PM EST

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RE: spray foam in crawl space?
Thanks Foamdude..... Let me get this right.. the absolute best thing to do would be to put down poly on my dirt floor, then spray 2-3 inches over the poly and continue up the foundation walls to the joist assemblies and DO NOT spray foam under the first floor/sub floor ? And if possible, a couple inches of cement on top of the spray foam would be ideal? Curious way not continue to and spray foam the sub floor to help heat loss in my house which was built in the 40's?

foamdude

Q&A Forums Registered User
Posted: 6/07/2012 4:41 AM EST

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RE: spray foam in crawl space?
small "f" if you please... :)
we do not put down poly on the grade as we have a vapor retarding membrane with our closed cell foam out at around 1.5-2" and we usually end up on the strong side of 2.5" on the slab...
and we hate shooting to poly,,,just a lousey interface,,,
correct,,no need to spray the subfloor as the crawl space is now a conditioned assembly,,if you hang a humdistat and thermostat down there you will see that it is real close to the conditions in the room above,,,even more so if it has that opening/entry to the adjoining basement...
(i spray the subfloor in the vented crawlspaces in flood plains where they ( the crawl space) cant be sealed off by code restrictions,,,spray the subfloor and box sills and rim joists assemblies..)

buildingsciencedotcom has some good reading about crawl spaces

Mason  

Moderator
Posted: 6/07/2012 10:14 AM EST

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RE: spray foam in crawl space?
I would defer to Foamdude on the vapor barrier on the floor.

Foamdude has more experience in his area with spraying dirt crawl spaces than i do. We would install a vapor retarder coating or spray on plastic when insulating freezer floors. The idea was that in a freezer, the vapor drive is ALWAYS from the outside in and if you allowed moisture to get into the foam that it would eventually get into the cement and it would buckle and crack. Much less likely in a residential construction where the interior temperature would most often times be hotter than the crawl space and the vapor drive would just pass through the foam and cement rather than freeze inside of it.

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