newbie - not sure which way to go on spray foam insulation

[Hankovitch]

Hello Bob,
You wrote.............Hank,
We are having closed cell spray foam sprayed on the underside of the floor joists (in the crawlspace) in three crawlspaces. In addition, they are doing the rim joist in the full height concrete floor basement where the utilities are. Two of the crawlspaces are a dirt floor. There currently is plastic over the floor but it looks 4mil and used and abused, the other one is the 22” (5cm) crawlspace height with no plastic. The owner of the company who came to the house, said I should replace that with 6mil plastic and have it overlap the walls and he would scim-coat the concrete walls down to this plastic on the floor. There is no plastic between the foam and the underside of the floor joist acting as a vapor barrier.
Is this the right thing to do?
I’ll try to read the article, but I need to finish clean/organize the basement as prep for the job…
Thanks,
Bob

Great idea, SPF on underside of the floor in the crawlspace(s), and the rim joist.
Are they spraying the rim joist on the outside or inside? Either way would be fine I can imagine. If outside the way I envision it they will srpay the underside of floor in the crawlspaces and continue the spraying to cover the rim joist....this would be very wise.

It may be a good idea to cover that dirt with plastic. I imagine they put the plastic there to minimize movement of the moisture from the ground coming up as water vapor, and that vapor condensing on the underside of the floor. Wise. If they spray the entire underside of your floor with closed cell foam this will GREATLY (emphasis intended) minimize water-caused rot of your porch. I imagine they will not spray everything under there, so the addition of new, thicker plastic to cover the dirt will be a good idea.
I might opt for simply having the Spray Guys continue spraying foam on the concrete walls (presumably down from the rim joist?) when they do the underside of the floor and the rim joist. This would be an excellent use of the foam and would help keep that full height basement insulated. I'm thinking that while skim coating with cement to hold the plastic in place is a good idea, it would be labor-intensive, and if you put the plastic down before they spray the foam, the foam will make the plastic adhere to the concrete at least as well as skim coating and be a far better use of labor. It will take the Spray Guys another 10 minutes to do this spraying, whereas skim coating could take far longer and be messier.

Regarding 'no plastic between the foam and the underside of the floor joist acting as a vapor barrier'......you won't need it. Closed cell foam is its own water AND vapor barrier - period.

No real need to read the entire article, print it out and look at the pictures, and read the 'punch line' (conclusion) at the end of the article. It will convince you that you will be forever happy with your decision to use the SPF.

Please let me know how it goes........I am quite interested.

Sincerely,

Hankovitch

 

[lobsta1]

I was under the impression that all these foam products must be covered with some kind of protective barrier. Could someone correct me if I am wrong? My house is also
on the Ma. NS. House was built in 1874 & I would love to get the porous fieldstone walls sprayed.
Al

 

[G-rott]

I stumbled onto this discussion too late to be of much help. I am a certified installer for a manufacturer that provides bot materials. Much hype and "salesmanship??" are associated with these products.

I have installed both materials(all three actually, I tested a soy based product), 1.8-2lb closed cell, and 1/2 lb open cell foams. In the majority of cases the open cell product is the best value, while the closed cell has uses where open cell would be less effective and/or detrimental.

One note on the use of closed cell especially for those of you where money is no object and you want to install the "best" (read most expensive) product. Closed cell foam is a vapor barrier...moisture will not travel through it. It can trap moisture that enters the structure and not allow the building to dry in a traditional manner.

An example is rain getting into a wooden roof deck, under the shingles and building paper due to a damaged flashing or roof damage. This moisture can rot the framing and sheathing materials without showing any leakage below, and not failing until major damage is done. The same can happen with condensation on pipes in the living space and small leaks in plumbing joints.

These are not faults of the product, however they are consequences of it's use.

Good luck with your project. I will answer any questions I can.

Garett

 

[Hankovitch]

Hello Al and Garett,

First to Al. I will share what information I have regarding your statement, "all these foam products must be covered with some kind of protective barrier"....
I will be applying Closed-Cell, 2-3 lb/cubic foot density, SPF (Sprayed Polyurethane Foam) as a roof. This must be covered by first a primer, then with an elastomeric (flexible) paint. Ultraviolet (UV) light will damage and ultimately destroy the SPF. To the best of my knowledge any SPF material is subject to this UV damage. This of course means that if the SPF is sprayed inside, and if you will cover the SPF with drywall or some other covering (excludsing the sun's rays), then this will constitute being 'covered with some kind of protective barrier(to UV light)'....
By the way, I know precious little about the soy-based product. Interestingly I did find out one very positive thing about the product which I did not know a few days ago when I posted something to this thread.....I see from one site that the soy-based product also has 'no nutritive value' to rodents or microbes, so the soy-based foam shares this good characteristic with the standard SPFs).
Perhaps Garett can share more information, comparing and contrasting open-cell, closed-cell, soy-based, etc..........foams.

Garett, you make an excellent point about the consequence (not fault) of SPFs.......repeated here.........thanks for sharing....
"One note on the use of closed cell especially for those of you where money is no object and you want to install the “best” (read most expensive) product. Closed cell foam is a vapor barrier...moisture will not travel through it. It can trap moisture that enters the structure and not allow the building to dry in a traditional manner. An example is rain getting into a wooden roof deck, under the shingles and building paper due to a damaged flashing or roof damage. This moisture can rot the framing and sheathing materials without showing any leakage below, and not failing until major damage is done. The same can happen with condensation on pipes in the living space and small leaks in plumbing joints. These are not faults of the product, however they are consequences of it’s use."
This stresses the importance of roof inspections (flashing areas particularly), and replacing your roofing material as it NEARS the end of its expected life, not AFTER the end of its expected life.

Garett, have you ever used high (2-3 lb) density SPF as a roof (covered by primer, then elastomeric paint)?
Do you (or anyone out there) know of someone who does this, know of someome who has had this done.....and who would be willing to communicate with me?

Thanks in advance.

Sincerely,

Hankovitch in Southwestern Wisconsin.

 

[coolidge]

Hankovitch, SPF has been used in the application you suggested, with excellent results. I have not seen any applications like this but have heard about and read some articles. SPF is used in alot of roofing applications on flat roof as a way to reduce energy, get a longer lasting roof system then conventional roofs. A website for you to check out and ask some questions. WWW.sprayfoam.com. As for covering SPF, you are correct about the primer and elastomeric coating but if used in a crawl space, attic, basement, by law SPF must be covered by either a fifteen minute thermal or ignition barrier, depending on where you are using it.

 

[Hankovitch]

Hello,

Thank you for the information regarding code-required 15 minute thermal barrier/covering on SPF in crawl space, attic, basement - that is VERY useful information. One certainly wants to do things according to the law, particularly to ensure that insurance will pay for things in the event of a fire!
I appreciate your informaiton.
I've visited the web site you mention, and will now go back to re-visit and post some queries, do some searches, etc.
Thanks for the reply, for the useful information, and for the recommendation to go to the sprayfoam web site.

Sincerely,

Hankovitch in SW Wisconsin

 

[G-rott]

Hankovitch,

I have not used spf as a roofing material, it is most commonly done in the south and has very good results.

As far as contrasting Open and Closed cell the only difference is the density and the cell structure. Closed cell foam is a foam produced when the "blowing agent" is trapped in the small bubbles that expand the plastic foam. This gas is slower to transfer heat energy giving the foam a higher R value per inch(6-7), also using more plastic material giving the foam its higher density( 1.5 - 2lb per board foot).

Open cell foam is produced with a blowing agent that expands more and ruptures the cell wall, letting the gas and heat produced to escape, as the gas escapes it is replaced with air and the cells collapse slightly mostly closing the rupture. The large cells filled with air do a good job of slowing heat transfer (r 3.2 - 4) and sealing against air movement. This is accomplished using 1/2 to 1/4 the plastic base material ( 1/2 to 1 lb per board foot)

When installing SPF you are paying for the component parts, the more insulating value you can create with a given amount of product the more cost effective the project.

As a rule of thumb the 1/2 lb foam is a little better value as the cost is less per R produced.

Garett

 

[Hankovitch]

Hello Garett,
Thank you for the information.
I visited the www.sprayfoam.com website and played through the entire Webinar titled “Longer Life at a Lower Cost” - A Thorough Spray Foam (SPF) Roofing Education. Great information.

I understand your cost/benefit analysis - certainly applies to inside spraying.

As the SPF we will use will be not only our insulation but also our 'siding' and our 'roof', it only makes sense to use closed cell at 3 lb/cubic foot density.
Interestingly, it may well be possible to put in all our windows and doors without any flashing, allowing the SPF to do the flashing.........still checking to be sure this will work and is wise. I will see if I can post this question on the www.sprayfoam.com website and let you know when I get an answer.
The SPF will function as our building envelope, roof, insulation, and siding.
It will be - three inches of SPF on the roof, at the two ends, and down the sides, to ~2 feet below grade, primed, and sprayed with an elastomeric paint as UV protectant.
This should function as:
(a) our roof,
(b) our 'siding', and
(c) our insulation, as well as,
(d) obviate the need of purchasing and installing Tyvek house wrap,
(e) elimate the need to purchase and install an interior (plastic) vapor barrier, and finally
(f) save the expense of purchasing and installing flashing for about 8 doors and 70 windows.
If the SPF + primer + paint will do (a) through (f), then at $3 to $5 per square foot it could be a bargain!

I also love the well-documented evidence that spraying the foam on the outside of a building actually increases the effective/measured R-value - several studies state that the effective (measured) R-value of closed-cell SPF is doubled if the foam is sprayed on the outside of a structure. I believe something to that effect was stated in the Webinar.

All 4 now.

Hankovitch in SW Wisconsin

 

[Hankovitch]

Hello again all.......
Hankovitch here to report on what we've done so far on our Barn-to-Home conversion project. We decided to "go" with the 3" of Close Cell Polyurethane Foam on the outside of our barn....from 3' below grade all the way up to the peak of the barn, and back down the other side once again to 3' below grade. A monolithic application of 3" thick foam on the barn, outside, covered with a polyurea paint as final coat to protect from UV light and the weather. Essentially as they re-did the Superdome roof after Katrina destroyed the EPDM roofing. We are doing this in stages, and I report here the current state of the project and what I will call the results.
We have dug out around the foundation of the 36' x 104' barn, 4 feet down…..pressure-washed the dirt from the foundation/footing……then applied 3" of SPF to the foundation (down 3' below grade), and applied 3" of SPF up the 8' high, 12" thick concrete wall of the milking parlor and up another foot……then sprayed a polyurea paint over the foam…..drain tile was put in around the foundation and runs to one of our ditches 300 feet from the barn……then we back-filled where they dug out around the foundation………then we also applied 2" of SPF inside the barn, to the milking parlor ceiling (underside of hay mow floor)………..we put 14 new windows, 3 new doors, and a new 7'x9' garage door in each end..………
In this 3,500 sq foot area (the former milking parlor) the only source of heat is passively from mother earth…down 4 feet the temp of the earth is approximately 50 degrees F…..
Bottom line on how well the insulation is working.
Since Jan 1, 2010 outside temp has ranged from +39 F to -14 F.
During that same time period the inside temp of the former milking parlor has ranged from +33 F to +37F.
The important thing to note is that, even though the outside temp dropped to 14 below zero, the inside temp always stayed above freezing….on some days inside the milking parlor has been as much as 47 degrees warmer than outside!
Note, this is with PASSIVE geothermal heating…..we do not have a heat pump, there is NO source of 'heat' for the barn other than what mother earth supplies by heat passively (and continually) coming up through the concrete slab of the milking parlor floor!
Furthermore, there is no 'earth berm' of the barn, the entire milking parlor is above ground.
Pretty awesome, I'd say…..

And, it will only get better as we…
- put on storm doors (for the three doors we put in),
- complete the back-filling (in some places the back-fill is over a foot low), and
- close off the openings of the two stairways with something better-insulating than the 3/4 OSB we now have covering the openings.

By the way, I'd love to hear how things went for the fellow who started this thread. What do you have to report?!

Sincerely,

Hankovitch in SW Wisconsin.

 

[gtown]

Sorry for the delay in posting. We went with the closed cell foam and we are very happy with it. The foyer floor does not feel as cool to the bare foot in the winter time. During installation, the stuff had a really strong ammonia smell to it, understand why there's not a diy kit. Used 6 or 7 mil plastic on the floors and the skim coated them to the cement walls as they did the joists. Not sure if that will make a difference, but it's done.

There is one thing that's happened since and I'm not sure if it's related or not. The bathroom double pane double hung window had the top outer pane crack - the whole pane. Almost looks like it was hit with something. But the screen on the outside shows no wear or damage. The outer wall around the window is brick or brick-faced. It's almost like the window frame tweaked forcing the glass to crack. The inner pane is fine and the two panes on the lower section of the double hung are ok as well. I wondered if the sprayfoam on the floor and rim joist around that section created a rigidity (if that's a word) that when the change in weather - got really cold - the frame because or the brick and now the floor did not have the play it once had. I could be way off and not trying to create any FUD around closed cell spray foam, I was just seeing what was different. There's no evidence of a BB or rock. The screen is intact, so it I don't think a snowball hit it.

The pellet stove install went fine and we love it. Last year we only fired it up when we were home. It took a while for the room to warm, but it was great. This year, we've turned the stove down at night to a lower temp and turned the fan to a lower speed and when we wake up in the morning, we just crank it back up and it's warm in no time. We like it so much, we are giving it some serious thought about putting an insert in the fireplace in the living room...