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Old 01-17-2012, 12:04 PM   #31
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Copied from Building Science.com Info-512 Crawlspace Insulation May 14, 2009.


Crawlspace walls should be insulated with non-water sensitive insulation that prevents interior air from contacting cold basement surfaces—the concrete structural elements and the rim joist framing. Allowing interior air (that is usually full of moisture, especially in the humid summer months) to touch cold surfaces will cause condensation and wetting, rather than the desired drying. The structural elements of below grade walls are cold (concrete is in direct contact with the ground)—especially when insulated on the interior. Of particular concern are rim joist areas—which are cold not only during the summer but also during the winter. This is why it is important that interior insulation assemblies be constructed as airtight as possible.

The best insulations to use are foam based and should allow the foundation wall assembly to dry inwards. The foam insulation layer should generally be vapor semi impermeable (greater than 0.1 perm), vapor semi permeable (greater than 1.0 perm) or vapor permeable (greater than 10 perm) (Lstiburek, 2004). The greater the permeance the greater the inward drying and therefore the lower the risk of excessive moisture accumulation.

Up to two inches of unfaced extruded polystyrene (XPS) (R-10), four inches of unfaced expanded polystyrene (R-15), three inches of closed cell medium density spray polyurethane foam (R-18) and ten inches of open cell low density spray foam (R-35) meet these permeability requirements.
In crawlspaces where the insulation material will need to be covered by a fire/ignition barrier, it may be acceptable to use fire-rated foil-faced insulations. However, such requires careful attention to supplemental moisture management strategies. With vapor impermeable facings on interior insulation, it is possible that water may accumulate between the insulation facing and the inside surface of the foundation wall. The airtightness of the assembly is, therefore, extremely important to prevent the exchange of air between this damp interface and anywhere else in the building.


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Old 01-19-2012, 09:31 AM   #32
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FYI on foam exposure:

If you do not provide the thermal and ignition barriers specifically mentioned in the code then you will need to get specific written approval from your local code official. Sprayed on intumescent paint, manufacturer claims, special foil facings, etc. are an exception to the code and need written approval to be considered acceptable.

Here's the exact code exerpt. Notice how it does not allow it to be left uncovered and/or painted without said approvals. Also note that the foil facings on the foam are not considered approved thermal/ignition barriers as they are not listed in the approved methods noted below.

SECTION 2603 - FOAM PLASTIC INSULATION

2603.4 Thermal Barrier. Except as provided for in Sections 2603.4.1 and 2603.9, foam plastic shall be seperated from the interior of the building by an approved thermal barrier of 1/2-inch (12.7mm) gypsum wallboard or equivalent thermal barrier material that will limit the average temperature rise of the unexposed surface to not more than 250degF (102degC) after 15 minutes of fire exposure, complying with the standard time-temperature curve of ASTM E 119 or UL 263. The thermal barrier shall be installed in such a manner that it will remain in place for 15 minutes based on FM 4880, UL1040, NFPA 286 or UL 1715. Combustible concealed spaces shall comply with Section 717.

2603.4.1 Thermal barrier not required. The thermal barrier specified in Section 2603.4 is not required under the conditions set forth in Sections 2603.4.1.1 through 2603.4.1.13.

(Sections 2603.4.1.1 -> 2603.4.1.5 and 2603.4.1.7 -> 2603.4.1.13 don't pertain to this topic)

2603.4.1.6 Attics and Crawl Spaces. Within an attic or crawl space where entry is made only for service of utilities, foam plastic insulation shall be protected against ignition by 1 1/2-inch-thick (38mm) mineral fiber insulation; 1/4-inch-thick (6.4mm) wood structural panel, particleboard or hardboard; 3/8-inch-thick (9.5mm) gypsum wallboard, corrosion-resistant steel having a base metal thickness of 0.016 inch (0.4mm) or other approved material installed in such a manner that the foam plastic insulation is not exposed. The protective covering shall be consistent with the requirements for the type of construction.

2603.9 Special approval. Foam plastic shall not be required to comply with the requirements of Sections 2603.4 through 2603.7 where specifically approved based on large-scale tests such as, but not limited to, NFPA 286 (with the acceptance criteria of Section 803.2), FM 4880, UL 1040 or UL 1715. Such testing shall be related to the actual end-use configuration and be performed on the finished manufactured foam plastic assembly in the maximum thickness intended for use. Foam plastics that are used as interior finish on the basis of special tests shall also conform to the flame spread requirements of Chapter 8. Assemblies tested shall include seams, joints, and other typical details used in the installation of the assembly and shall be tested in the manner intended for use.
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Old 01-19-2012, 01:38 PM   #33
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Exactly, and that is why the Code in some respects is wothless.

It would rather me place wood structural panels (food for termites) particle board (food for termites), hardboard (food for termites), gypsum board (food for mold) inches from a dirt floor.

Also, the foam must be covered by one of those materials so none of the foam is exposed. That means all sides, ends too, not just the front surface,

Only viable materials are mineral fiber insulation and corrosion resistant steel. I wonder how expensive it would be to place .016 inch steel panels in a crawlspace? No, I won't be doing that and I have no idea where to get 1.5 inch thick mineral fiber insulation.

Last edited by Earnie; 01-19-2012 at 01:46 PM.
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Old 01-19-2012, 03:15 PM   #34
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Another way I insulate crawlspace walls is to glue pins to the wall. Then push on Roxul (rock wool insulation) and apply a cap over the pin. It is sort of like a large pop rivet application. The contact glue used for the pins smells and needs good ventilation and 24 hours to cure. So it is a two day application. But meets codes, does not attract mold, pests and insects. And is an inexpensive method. You can either go with 3" Roxul or two layers to get 6" depth.
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Old 01-19-2012, 05:29 PM   #35
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The Roxul is vapor-permeable and would not slow vapor-drives, the whole point of foamboard (insulates/ Class 2 vapor retarder) to control it to a manageable level.

If the board manufacturer has an Evaluation Report for the product, it may not require a thermal/ignition barrier covering when meeting their requirements; http://www.ncfi.com/Insulation/uploa...%20SF0608L.pdf

Earnie, most from the link I sited:

Owen Corning pink board in attics: #4.2.1: http://commercial.owenscorning.com/a...79af27e5d.pdfI

I am merely showing the reason spray foam professionals may not cover it, and if you are under an “I” Code, there is information you may be missing. I would cover it whenever convenient to do so, just for the fire safety issue.

Here is one from Dow, follow the other links/questions to learn more;
http://dow-styrofoam.custhelp.com/ap...KkNueDl5R2s%3D

You can check the certain type listing: http://dow-styrofoam.custhelp.com/app/answers/detail/a_id/3891/~/what-are-the-astm-c578-classifications-for-styrofoam%E2%84%A2-brand-extruded


Thermal and ignition barrier Code understanding: http://www.biobased.net/architects/W...0for%20SPF.pdf

RMAX foam boards in attics/crawlspace with no covering 1. if vented space; 2. combustion air provided; 3. board max. density 2#c.ft., max. thickness of 4-1/2” : http://www.icc-es.org/reports/pdf_fi...S/ESR-1864.pdf

Hardi meets CA Building Code with this report, otherwise you couldn’t install Hardie there: http://www.icc-es.org/reports/pdf_fi...S/ESR-1844.pdf

If the manufacturer has an Evaluation Report on that specific product, follow the installation guidelines and usage listed therein. ESP used in attics/crawls; 1. entry only for service, NO storage; 2. no interconnecting attic or crawlspaces; 3. air in attic/crawl NOT circulated to parts of building; 4. attic venting as per code; 5. crawlspace venting as per code: http://www.icc-es.org/reports/pdf_fi...S/ESR-1788.pdf

AdvanTech roof and wall panels meet code-prescribed water-resistive barrier without one; http://www.icc-es.org/reports/pdf_fi...S/ESR-1785.pdf

Handi-Foam Class 1, SPF does require an ignition barrier in attics/crawls; http://www.icc-es.org/reports/pdf_fi...S/ESR-2717.pdf

List of products/manufacturers, watch the code colors for year they apply, found at the end of list; http://www.icc-es.org/reports/index.cfm?list=list

Obviously all foam/boards cannot be left uncovered and the air cannot exchange to a living space, products vary, read the report, if none is given- follow the Code (thermal or ignition barrier) in use along with your Building Inspector. Many jurisdictions have local amendments to the prescriptive “I” Codes. You may be in a State that does not use an I-Code, follow the AHJ.

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Old 01-20-2012, 05:48 AM   #36
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The vapor barrier is already addressed since you should always have the poly on the floor and up to the sill plate.

as far as foam this from code in NC
Fire Safety
A key element in residential fire safety is
fireblocking between different levels in a home.
Fireblocking requirements already exist in the
residential building code, but allow the use of
porous materials like fiberglass or rock wool
insulation. North Carolina has improved these
requirements to require the use of non-porous
materials for fireblocking in crawl spaces.
Foam plastic insulation receives special
scrutiny in residential building codes because
some foam insulations have the potential to
release toxic or flammable gases when heated,
or they can accelerate the spread of a fire if
they ignite. To reduce these risks, most codes
require a thermal barrier (typically 1/2 inch
[13 mm] gypsum board or equivalent) or an
ignition barrier (typically 3/8 inch [10 mm]
gypsum board or equivalent) over foam
insulation. However, several foam insulation
products have been designed and tested to
reduce or eliminate those risks. Such products
can be installed without a thermal barrier or
ignition barrier with the appropriate
documentation.
Seal all plumbing, electrical, duct,
plenum, gas line and other wiring
penetrations through the subfloor
with non-porous materials. Rock
wool or fiberglass insulation alone
is not sufficient.
Provide documentation of product fireratings
(in the International Code Council
National Evaluation Report (ICC NER) for
the product) to allow installation of
exposed foam insulation without a thermal
barrier or an ignition barrier, if applicable
Provide documentation of fire-rating to
allow installation of exposed facing
materials on batt insulation in the band
joist or pony walls, if applicable
Do not use a crawl space to store
gasoline, solvents, or any tools or
materials that present a fire hazard.
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Old 01-20-2012, 06:40 AM   #37
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"The vapor barrier is already addressed since you should always have the poly on the floor and up to the sill plate."

Sorry, but I won't be doing that either. NC, and probably most of the South, has termites. I would never install plastic vapor barrier from the dirt floor up to the sill plate. I don't recall the reference, but I believe there is a requirement to have a 3 inch inspection area below the sill plate to check for termite activity if the wall is covered.

Maybe I'm ignorant of the facts (and I have asked this before), but why would I want a plastic vapor barrier covering the block wall? Isn't that trapping moisture between the block wall and the plastic?

Here is an easy way to remedy this issue. Does anyone have the name of a company that makes a code compliant and fire rated foam board that can be used to cover crawlspace walls? Specific product name will be helpful. What I mean is, something more than "check Dow or Owings Corning".
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Old 01-20-2012, 10:18 AM   #38
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I love how GBR deletes my post and continues on giving vague mis-leading responses. Bob Mariani posted the code for NC and it says the same as what I posted. YOU NEED BUILDING OFFICIAL APPROVAL TO LEAVE FOAM EXPOSED. No exceptions! I can't say it in any plainer english...please stop the vague information when dealing with life safety issues. It's misleading and life threating.
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Old 01-20-2012, 04:54 PM   #39
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Quote:
Originally Posted by AGWhitehouse View Post
I love how GBR deletes my post and continues on giving vague mis-leading responses. Bob Mariani posted the code for NC and it says the same as what I posted. YOU NEED BUILDING OFFICIAL APPROVAL TO LEAVE FOAM EXPOSED. No exceptions! I can't say it in any plainer english...please stop the vague information when dealing with life safety issues. It's misleading and life threating.
The most commonly used rigid foam board used on crawlsapce walls is probably Thermax Sheathing and it has passed FM 4880 which means it does not require ignition barrier protection. You can look it up by going to dowbuildingsolutions.com


And almost all professional spray foam does not need an ignition barrier. Where do you get this info? I do this for a living! And I pass inspections every day in many many towns both in CT and NY


Many closed cell foam manufacturers have passed testing that shows their materials do not require an Ignition Barrier in applications where an Ignition Barrier is required because those materials pass the ignition barrier test without any protection and comply with AC377 Apendix X. An ignition barrier is the only protection required in many interstitial space applications of foam chracterized by limited or no access, containing wires, pipes, ducts, or mechanical devices, air from this space cannot communicate with other spaces
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Old 01-20-2012, 05:02 PM   #40
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Quote:
Originally Posted by Earnie View Post
"The vapor barrier is already addressed since you should always have the poly on the floor and up to the sill plate."

Sorry, but I won't be doing that either. NC, and probably most of the South, has termites. I would never install plastic vapor barrier from the dirt floor up to the sill plate. I don't recall the reference, but I believe there is a requirement to have a 3 inch inspection area below the sill plate to check for termite activity if the wall is covered.

Maybe I'm ignorant of the facts (and I have asked this before), but why would I want a plastic vapor barrier covering the block wall? Isn't that trapping moisture between the block wall and the plastic?

Here is an easy way to remedy this issue. Does anyone have the name of a company that makes a code compliant and fire rated foam board that can be used to cover crawlspace walls? Specific product name will be helpful. What I mean is, something more than "check Dow or Owings Corning".
NC Code requires a 3" termite inspection zone below the top of the foundation wall yes.
So what if you 'trap' moisture between the poly and the wall? Pratically the only time I don't spec poly up the walls is if it's poured concrete and largely impervious.
Block and Brick walls absorb moisture and release it (typically) as humidity into the crawl. Varies based on depth below grade, waterproofing, etc.
But the poly isn't stuck to the wall to create a back-side waterproofing. Fastened and caulked at the top, it would allow the vapor to condense and run down to the dirt. You know, like a vapor barrier.
Then, put your insulation on the poly and it's protected.
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Old 01-20-2012, 05:38 PM   #41
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CSM,

I understand what you are doing and how you are applying the poly. Is there tested and documented proof that installing the poly to the brick will not cause a problem long term?

That's great poly can be used but I need to be sure I'm not fixing one problem and creating a bigger one.

I'll search and see if I can find where I read placing poly on the crawlspace was wrong.
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Old 01-20-2012, 07:39 PM   #42
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Hmmmm, a study that proves something doesn't cause a problem... let me look. I'm thinking the advanced energy studies address it.
If nothing else, NC codes specifies for sealed crawls a 100% wall to wall poly, OR it's to run up the wall to 3" from band sill.
Curious, what problem(s) do you think it would cause? I've read that up north spray foam on the foundation walls can cause the moisture to stack until it reaches the band sill and rots it. Poly on the wall doesn't do that, as it doesn't seal the material.
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Old 01-20-2012, 08:41 PM   #43
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CSM,

I read your reply to imply that you have no hard data. The "advanced energy studies"? What advanced energy studies? Sources please.

Where exactly did Raleigh get the data to support what they currently have in the code regarding sealing crawlspaces? Remember, this is the same organization that required crawlspace vents which draw in hot humid air into a cool dry crawlspace.

I called Raleigh yesterday and left a message about this exact issue. So far no reply. They were in a training class.

Sorry, but you're not convincing me that the plastic won't cause a future problem.
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Old 01-20-2012, 09:12 PM   #44
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I'm not here to convince you of anything. It's your house - do what you want within state code requirements. Like any other system within your house, monitor it, be aware of what's going on. I don't care what you do, but vented crawl spaces leave the underside of the home bathed in humidity.
Advanced Energy studies - crawlspaces.org. They've done I think 3 studies now on sealed crawl spaces, the first here in NC. You could have just done a google search.
They didn't require vents to 'draw in' moisture from outside. Back in the 'old days' vents weren't required, and they started requiring them to help clear OUT the humidity and moisture that will build in a crawl space. Still lunacy in my opinion, but a lot of crawls work okay with it. Others are horrendous.
If you think poly on the walls will cause a problem, which you still left unstated, then by all means don't do it.
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Old 01-20-2012, 09:37 PM   #45
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No problems with what you just wrote.

I have no idea what might happen over time with poly on the walls. That's why I'm asking. I'd like to read a study or report on testing that has been done. From there I can make an informed decision.

Thanks for the link to crawlspaces.org.

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