# Insulation 'Great Stuff' by DOW Chem.



## jh1999 (Dec 5, 2010)

See pic please. I circled in RED the effect I would like but can't seem to get the "spray effect" Any help please??????? When I spray I get clumps that roll off to the bottom of joist.


----------



## 95025 (Nov 14, 2010)

The product you're using will not give you the results you desire. Great Stuff is not a spray-on insulation. It's an expanding crack and hole filler.

I wish I could point you toward a product that will do what you want, but I'm not aware of one. Hopefully somebody else can chime in and help.


----------



## Mike in Arkansas (Dec 29, 2008)

There are several sources of DIY spray foam kits online. Do a google search. Obviously going to contain more than a can of Great Stuff though.


----------



## md2lgyk (Jan 6, 2009)

Such kits aren't cheap, either.


----------



## DangerMouse (Jul 17, 2008)

GSF should work in this case though, just start at the bottom and work lines up as you go.

......unless this is not a photo of your area.

DM


----------



## DexterII (Jul 14, 2010)

Or use rigid foam board, with caulk or GSF to seal the edges.


----------



## gma2rjc (Nov 21, 2008)

What kind of spray are you using?

Do a google search for Foam-It-Green. That's what I used and it worked very well and it's easy to do. It was my first try at that kind of project.

If I remember right, there are two different kinds of foam to choose from. One of them is for spraying wide areas like walls or rim joists and one doesn't spray as wide an area. There are also two kinds of tips to use and I think both kinds come with the tanks. Order extra tips because once you stop spraying for more than 30 seconds, the tip has to be replaced - they just snap off and on, it's easy.

I know there is another company that sells to the general public and I think it's called Tiger Foam or something similar. You could look it up and compare prices. I think I paid $700+ for the kit and $95 for shipping. But there are smaller kits for smaller jobs that cost less.


----------



## jh1999 (Dec 5, 2010)

DexterII said:


> Or use rigid foam board, with caulk or GSF to seal the edges.


 This is probably the path I'll take. Thanks!!


----------



## DangerMouse (Jul 17, 2008)

DexterII said:


> Or use rigid foam board, with caulk or GSF to seal the edges.


This is exactly what I did for my perimeter beams with the foam baffle vents.
(scrap foam from the walls cut out for the baffles, GSF to seal/glue/fill gaps.)
It worked fine! Dunno why I didn't mention it before.... :laughing: There are pictures even here somewhere.....

DM


----------



## railman (Jun 29, 2010)

DexterII said:


> Or use rigid foam board, with caulk or GSF to seal the edges.


Yes, in my home I insulated the area with 6" insulation, then cut foam board to fit, then caulked.


----------



## Gary in WA (Mar 11, 2009)

The rim joist is a large source of air infiltration because it swells and shrinks with the seasons; http://www.buildingscience.com/documents/insights/bsi-023-wood-is-good-but-strange/

SPF or rigid foam board directly on the rim wood, air seal *then *add fiberglass (if required by local code), though IRC now allows foam (up to 3-1/4”) left uncovered in rim area; http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_3_sec016_par015.htm?bu2=undefined

The fiberglass insulation should never be between the foam board and exterior; 

1. It allows moist air in to saturate, condense and mold on the rim joist (and fiberglass), http://www.buildingscience.com/documents/information-sheets/critical-seal-spray-foam-at-rim-joist/

http://www.inspectapedia.com/sickhouse/FiberglassMold.htm

You will also lose 60-70% of R-value with wet insulation; add another 20-30 % lost to convective loops and wind-washing the fiberglass. Sorry, framingrailman, don’t shoot the messenger……

2. Any holes from plumbing/wiring need to be plugged with foam (not air-permeable f.g.) to stop the “stack effect” of energy loss due to pressure/temperature differences at attic/basement, or crawlspace. http://www.wag-aic.org/1999/WAG_99_baker.pdf

Foil faced foam board on walls may be approved, left exposed----check with the local AHJ. You’ll want to change it out if/when future finishing.(No foil-faced below grade in basement- vapor barrier).
Remember to fire-block the frame wall every 10' horizontally and seal the top plate to concrete continuous with approved fire-blocking material. AHJ may accept compressed f.g. batt there. Imperative to stop an outlet fire in wall from spreading to joist bay, surfacing at outlet across basement in wall at other end of house, on floor above or attic.

Gary


----------



## railman (Jun 29, 2010)

I'm going to do an inspection...Thanks, GBR


----------



## carlosc (Nov 23, 2011)

*Foam*

As one poster mentioned, what is happening is that you are probably using something like Great Stuff. Your picture is showing a professional installation of foam insulation. So basically, you want to avoid the products 'in a can.' You want to use a foam kit, and they often come in a tank that looks like the tank on your gas grill. They have a 'gun' which allows you to change the flow rate. Take a look at Handi-Foam products. Here is a link to help you out with:
http://www.teksupply.com/contractor/supplies/cat1a;ts_handifoam_insulation.html

They have a guide to help you as well:
http://www.teksupply.com/contractor/supplies/ExternalPageView?pageKey=EXTERNAL_PAGE_3004

On the guide, that first picture shows a guy using a gun to spray between rafters. Like what you want to do.

Good luck jh1999

Cheers
Carlos


----------



## cbaur88 (Jan 25, 2011)

DexterII said:


> Or use rigid foam board, with caulk or GSF to seal the edges.


This is another option I've been kicking around to insulate the ceiling of my crawl space. However I am not sure what to do for a vapor barrier. Forgive me for all the questions I am an anal try to do it right DIYer.

Does rigid foam need a vapor barrier? If so do they make it with a vapor barrier? Also would it be a bad idea to do a hybrid of rigid foam sealed w/ GSF and fiber batts? Should the batts go in first or the rigid foam w/ GSF then the fiber? I would think the rigid foam first then the fiber but want to be sure. Thanks in advance


----------



## Windows on Wash (Aug 30, 2011)

The vapor barrier in your crawl space should be across the floor and sealed to the step wall.

If you were insulating the floor and not the outside wall, the rigid foam would go across the joists with the cavities being properly filled with FG, Cellulose, or mineral wood.

Flash and batt works pretty well in this case.


----------



## cbaur88 (Jan 25, 2011)

Windows on Wash said:


> The vapor barrier in your crawl space should be across the floor and sealed to the step wall.


Thanks Windows, I think I may have used the wrong choice of words. I understand the vapor barrier being on the floor, I currently have one, it's older but its there. Maybe the word I should have used is vapor retardant? For instance facing of fiberglass batts as I understand is installed toward the warm part of the house creating a vapor barrier or vapor retardant. That is what I meant when talking about the rigid foam, etc...


----------



## Windows on Wash (Aug 30, 2011)

Vapor retarder is correct.

What is the floor above the crawlspace covered with? If it is vinyl or another vapor impermeable substrate, you don't, nor should you, have one.

If you apply a good layer of rigid foam across the rafters, you can skip the vapor retarder altogether as the plywood is providing a Class 3 retarder already.


----------



## cbaur88 (Jan 25, 2011)

Windows on Wash said:


> Vapor retarder is correct.
> 
> What is the floor above the crawlspace covered with? If it is vinyl or another vapor impermeable substrate, you don't, nor should you, have one.
> 
> If you apply a good layer of rigid foam across the rafters, you can skip the vapor retarder altogether as the plywood is providing a Class 3 retarder already.


The living space above the crawlspace is the dinning room, living room, and also the kitchen. The kitchen is floor is ceramic tile with vinyl underneath. The living room and dinning as of right now are covered in your basic carpet. 

This is an older home and I believe the correct name for the type of flooring in my home is plank so I am not sure if that provides retarder. 

With that said Windows on Wash what would you do or advise? What I am thinking is cutting to size and putting in rigid foam flush against the bottom of the plank flooring between the joists & sealing it with great stuff and then adding some unfaced batt fiber over it. Some of the rigid foam i am seeing online like HD is saying it's got moisture-resistant facers and has radiant-barrier-quality reflective foil, not sure I want that or not. That's where I need some advice as well, thanks again you've been very helpful. :thumbsup:


----------



## Windows on Wash (Aug 30, 2011)

You have a vapor barrier (less than 0.1 perm) on the warm side with the vinyl floor tile at this point so you want to make sure you don't use a vapor barrier on the underfloor insulation. If you do, you will be creating a double vapor barrier which is not ideal and will just trap moisture in the cavity.

Make sure the poly on the floor is continuous and sealed to the block wall holding down ground source moisture.

In a perfect world, I would spray 2-3" of closed cell foam on the under floor. This will give you and R-12-18 and still leave a permeability rating of about 1 or so. This will reduce the surface temperature of the underfloor considerably so you should not have any condensation issues in the summer months.

After that, I would either put up Roxul or unfaced batts and install a rigid EPS foam over the joists to interrupt the thermal bridging of the floor.

If you go the exposed foam route, you will need some sort of ignition barrier (assuming the crawlspace if just for utilities and not storage) over the foam.

You could also roxul across the joists in lieu of the foam and they you don't need an ignition barrier.


----------



## cbaur88 (Jan 25, 2011)

Windows on Wash said:


> You have a vapor barrier (less than 0.1 perm) on the warm side with the vinyl floor tile at this point so you want to make sure you don't use a vapor barrier on the underfloor insulation. If you do, you will be creating a double vapor barrier which is not ideal and will just trap moisture in the cavity.
> 
> Thanks Wash, only the kitchen which makes up less then half the living space above the crawl space has the vinyl and tile. The rest of the space in question to my knowledge only has the plank floor, carpet cushion, & then carpet. Not sure if this is huge concern and I need to vapor barrier the rest of the living space while avoiding creating a double v. barrier below the kitchen area.
> 
> ...


Thanks again for all your help!


----------



## Windows on Wash (Aug 30, 2011)

No need to worry about the vapor barrier question in the other locations.

You don't need to supply one but you just need to take special care not to install one where you already have one in place (i.e. vinyl floor tile).

Just go ahead and install a duplicate vapor barrier across the floor. You existing one is probably torn in some locations already. No need to remove the existing one. Just go over the top and seal it to the wall and any penetrations in it (i.e. pillars, support beams, etc).

The foam can be kept at room temperature for a will and will dispense just fine. The surface temperature of the floor from the underside will be somewhat close to room temperature so you are okay on that end of things too.

You can put rigid foam up there as well but you want to stay near that perm rating of 1-2 on the kitchen section. Fiber faced iso is usually about 1 perm, unfaced XPS will be about 1.2 at 1", unfaced EPS (Type-I) will be about 1 perm at 5". Make sure if you go the rigid route that it is all taped and sealed up well. 

The rigid foam across the joists. The spray foam would be covered by the cavity insulation.

Thanks to my buddy Dana for most of the perm ratings.


----------



## cbaur88 (Jan 25, 2011)

Thanks a bunch again Wash I sincerely appreciate it.


----------

