Spray foam attics - InspectionNews

Ken Larson · #1 (**permalink**) 12-20-2007, 07:55 AM

This is a first for me. In a brand new neighborhood all the homes were being constructed with expandable foam spray in the attics. No insulation between the ceiling joists and no visible attic ventilation at the back of the attic. Only ventilation was one gable vent.

I sure don't know of any waivers in the IRC that exempts this material from standard building practices. I still wrote them up for lack of insulation and ventilation.

Anyone seen this lately or know about this type of insulation method?

Scott Patterson · #2 (**permalink**) 12-20-2007, 07:59 AM

That looks like an http://www.icynene.com/ installation. Good stuff if it is done properly. But what is pictured and with your description it does not sound like it was done properly.

By chance did you touch the foam? Was it soft and spongy or did it dent when you pushed on it?

With Icynene you do not insulate the attic floor. The attic is sealed off and should not have any ventilation from the outside. Any gas fired equipment must be provided with outside combustion air.

David Banks · #3 (**permalink**) 12-20-2007, 08:55 AM

Adding to Scott.
BSD-149: Unvented Roof Assemblies for All Climates —

Jerry Peck · #4 (**permalink**) 12-20-2007, 02:03 PM

Adding to Scott and David ...

From David's link:

Controls Rain Leakage – Closed-cell spray foam has negligible water permeability, minimal water absorption, and excellent adhesion allowing it to act as a secondary rainwater barrier to limit damage when primary roof assembly rainwater control membranes leak. Rainwater migration is severely limited due to the low water transmission and high adhesion (“waterproofing”) characteristics of the foam and damage is limited to the area immediately adjacent the hole in the primary rainwater control membrane. This tends to contain the damage, making it easier to identify the source and preventing it from spreading throughout the assembly and to interior finishes which can be costly to repair.

Yep. Just what some of us have been saying, but were told differently in the past ... at least now they are being honest about it.

"limit damage when primary roof assembly"

"Rainwater migration is severely limited"

"and damage is limited to the area immediately adjacent the hole"

Means that you will never see the leak from inside, and, of course, you will not see the leak outside, thus, one day, someone will be on the roof and the rotted roof decking will fall in ... because the leak has been "contained" right up against the roof sheathing.

"This tends to contain the damage, making it easier to identify the source and preventing it from spreading throughout the assembly and to interior finishes which can be costly to repair."

Huh? "making it easier to identify the source"? Ain't no way you are going to see the leak ... oh, I get it ... when the person steps through the roof sheathing it will be "easier to identify the source" by looking for the hole they stepped through - OH! I GET IT NOW!

Yeah, right.

That, however, seems to be the only major drawback to this stuff.

Scott,

"But what is pictured and with your description it does not sound like it was done properly."

What am I missing, other than Ken saying "Only ventilation was one gable vent.", which, if that part of the attic is also Icynene, there should not be any ventilation.

Scott Patterson · #5 (**permalink**) 12-20-2007, 04:13 PM

Quote:

Originally Posted by Jerry Peck

Scott,

"But what is pictured and with your description it does not sound like it was done properly."

What am I missing, other than Ken saying "Only ventilation was one gable vent.", which, if that part of the attic is also Icynene, there should not be any ventilation.

The ventilation is one and the other would be the depth of the foam. It does not look like it has been sprayed deep enough, you can see the rafters and the collar ties transmitting though the foam. You should not be able to see them.

Jerry Peck · #6 (**permalink**) 12-20-2007, 05:49 PM

Quote:

Originally Posted by Scott Patterson

It does not look like it has been sprayed deep enough, you can see the rafters and the collar ties transmitting though the foam. You should not be able to see them.

Wouldn't that depend on what R-value is required? If that is only an R-19 area, wouldn't that be sufficient?

Scott Patterson · #7 (**permalink**) 12-20-2007, 07:11 PM

Quote:

Originally Posted by Jerry Peck

Wouldn't that depend on what R-value is required? If that is only an R-19 area, wouldn't that be sufficient?

I don't know. That would be logical, but then that stuff does not do real good on my logic meter!

Jim Luttrall · #8 (**permalink**) 12-20-2007, 07:29 PM

R value is measured per inch just like anything else.
Sloppy work though.
I agree there should be NO ventilation, the conditioned envelope is moved from the attic floor to the roof just like a cathedral ceiling.
I still have problems with the exposed foam and covering it or not.
It is separated from the living area by the ceiling drywall, but does that meet the requirements of the IRC?
I have seen this in a few model homes and one retro-fit of an older home (which was a total mess), but never anything that has passed muster with a local AHJ.
I would be interested in the take on the applicable codes.

Jerry Peck · #9 (**permalink**) 12-20-2007, 07:42 PM

Quote:

Originally Posted by Jim Luttrall

I would be interested in the take on the applicable codes.

It is allowed.

From the 2006 IRC.

R806.4 Conditioned attic assemblies.Unvented conditioned attic assemblies (spaces between the ceiling joists of the top story and the roof rafters) are permitted under the following conditions:
- 1. No interior vapor retarders are installed on the ceiling side (attic floor) of the unvented attic assembly.
- 2. An air-impermeable insulation is applied in direct contact to the underside/interior of the structural roof deck. “Air-impermeable” shall be defined by ASTM E 283.
- - Exception:
- - - In Zones 2B and 3B, insulation is not required to be air impermeable.
- 3. In the warm humid locations as defined in Section N1101.2.1:
- - 3.1. For asphalt roofing shingles: A 1-perm (5.7 × 10 -11 kg/s ⋅ m2 ⋅ Pa) or less vapor retarder (determined using Procedure B of ASTM E 96) is placed to the exterior of the structural roof deck; that is, just above the roof structural sheathing.
- - 3.2. For wood shingles and shakes: a minimum continuous 1/4-inch (6 mm) vented air space separates the shingles/shakes and the roofing felt placed over the structural sheathing.
- 4. In Zones 3 through 8 as defined in Section N1101.2, sufficient insulation is installed to maintain the monthly average temperature of the condensing surface above 45°F (7°C). The condensing surface is defined as either the structural roof deck or the interior surface of an air-impermeable insulation applied in direct contact with the underside/interior of the structural roof deck. “Air-impermeable” is quantitatively defined by ASTM E 283. For calculation purposes, an interior temperature of 68°F (20°C) is assumed. The exterior temperature is assumed to be the monthly average outside temperature.

Matt Fellman · #10 (**permalink**) 12-20-2007, 07:45 PM

That stuff looks like a total nightmare.... mainly because of what Jerry says.... until someone steps through the roof deck you'd never know you have a problem..... Do they even put attic access hatches in these houses? If so, why? It's like that old joke about just welding the hoods of the import cars shut.... you just throw them away when there's a problem.

Jerry Peck · #11 (**permalink**) 12-20-2007, 07:48 PM

Quote:

Originally Posted by Matt Fellman

Do they even put attic access hatches in these houses? If so, why?

Does not compute ... one has nothing to do with the other???

Jim Luttrall · #12 (**permalink**) 12-20-2007, 10:14 PM

Jerry, Thanks for the 2006 IRC language, that is not in the 2003 that I have. Is the language fro R314.1.2 and R314.14.2.3 changed? Seems you brought it up in the past that foam had to be covered. When I read it, it seems a little ambiguous as to where the covering has to be. As I understand R314.2.3 Attics and crawlspaces, All foam plastics have to be protected from ignition, and the attic pictured would not fly. Any thoughts?

Matt Fellman · #13 (**permalink**) 12-20-2007, 10:46 PM

Quote:

Originally Posted by Jerry Peck

Does not compute ... one has nothing to do with the other???

I'm just joking around.... I can't imagine trying to do any work to anything in the attic after that gunk is sprayed all over the place.... So, what would be the point of getting in there.... hence the 'welded shut hood analogy' - I suppose if it needed this much explanation the joke was lost......

Eric Shuman · #14 (**permalink**) 12-21-2007, 07:56 AM

Ken,

I guess this is starting to catch on in this area as I inspected a newly built home this week with the same stuff (probably the same installer as it is so uncommon). I was initially was alarmed when I was on the roof and did not observe any exhaust venting. It does require that no attic ventilation be present, presumably to keep the moisture out. I wrote it up as unconventional but allowed when properly installed and mentioned the lack of ventilation . I then of course stated that I was not qualified to properly evaluate the installation due to my unfamiliarity with the material and application.

This house also had a geothermal HVAC system, another uncommon thing in our area. Of course no one told me any of this when they scheduled the appointment even though they were aware. Would have been nice to do some research before I went.

I didn't like the fact that I could not see the framing connections of the roof structure. I listed the missing weather seal at the small constructed door between the garage attic space an the sealed attic area. I did write up the fact that they had encased the water heater b-vent in the stuff (see photo).

If anyone has any good install info on this stuff I would like to see it. The icycnene web site has some info.

Eric

brian schmitt · #15 (**permalink**) 12-21-2007, 02:12 PM

one problem with this stuff is composition shingle manufacturer's may not honor their warranty with this methodology.i think elk brand may be one of the only companies to approve of this method. i guess heat build up damages some comp.

Jerry Peck · #16 (**permalink**) 12-21-2007, 04:53 PM

Quote:

Originally Posted by Matt Fellman

I'm just joking around.... I can't imagine trying to do any work to anything in the attic after that gunk is sprayed all over the place....

Matt,

Actually, it is much easier to work on everything in the attic (of course, referring to what is below the insulation on the roof sheathing) - no insulation to get in the way and have to be moved around to work on whatever.

And, how often do you work on 'the roof sheathing' as compared to working on the wiring, ducts, recessed lights, etc.? Never?

Those attics are a breeze to inspect and you can see many things 'done wrong', with fire stopping, framing, you name it - simply because you can now see it out in the open.

Jerry Peck · #17 (**permalink**) 12-21-2007, 05:17 PM

Quote:

Originally Posted by Jim Luttrall

Is the language fro R314.1.2 and R314.14.2.3 changed?

Jim,

It has all changed.

SECTION R314
- FOAM PLASTIC
- - R314.1 General.
The provisions of this section shall govern the materials, design, application, construction and installation of foam plastic materials.
- - R314.2 Labeling and identification. Packages and containers of foam plastic insulation and foam plastic insulation components delivered to the job site shall bear the label of an approved agency showing the manufacturer’s name, the product listing, product identification and information sufficient to determine that the end use will comply with the requirements.
- - R314.3 Surface burning characteristics. Unless otherwise allowed in Section R314.5 or R314.6, all foam plastic or foam plastic cores used as a component in manufactured assemblies used in building construction shall have a flame spread index of not more than 75 and shall have a smoke-developed index of not more than 450 when tested in the maximum thickness of 4 inches (102 mm), provided the end use is approved in accordance with Section R314.6 using the thickness and density intended for use.
- - - Exception: Foam plastic insulation more than 4 inches thick shall have a maximum flame spread index of 75 and a smoke-developed index of 450 where tested at a minimum thickness of 4 inches, provided the end use is approved in accordance with Section R314.6 using the thickness and density intended for use.
- - R314.4 Thermal barrier. Unless otherwise allowed in Section R314.5 or Section R314.6, foam plastic shall be separated from the interior of a building by an approved thermal barrier of minimum 0.5 inch (12.7 mm) gypsum wallboard or an approved finish material equivalent to a thermal barrier material that will limit the average temperature rise of the unexposed surface to no more than 250°F (139°C) after 15 minutes of fire exposure complying with the ASTM E 119 standard time temperature curve. The thermal barrier shall be installed in such a manner that it will remain in place for 15 minutes based on NFPA 286 with the acceptance criteria of Section R315.4, FM 4880, UL 1040 or UL 1715.
- - R314.5 Specific requirements. The following requirements shall apply to these uses of foam plastic unless specifically approved in accordance with Section R314.6 or by other sections of the code or the requirements of Sections R314.2 through R314.4 have been met.
- - - R314.5.1 Masonry or concrete construction. The thermal barrier specified in Section R314.4 is not required in a masonry or concrete wall, floor or roof when the foam plastic insulation is separated from the interior of the building by a minimum 1-inch (25 mm) thickness of masonry or concrete.
- - - R314.5.2 Roofing.The thermal barrier specified in Section R314.4 is not required when the foam plastic in a roof assembly or under a roof covering is installed in accordance with the code and the manufacturer’s installation instructions and is separated from the interior of the building by tongue-and-groove wood planks or wood structural panel sheathing in accordance with Section R803, not less than 15/32 inch (11.9 mm) thick bonded with exterior glue and identified as Exposure 1, with edges supported by blocking or tongue-and-groove joints or an equivalent material. The smoke-developed index for roof applications shall not be limited.
- - - R314.5.3 Attics. The thermal barrier specified in Section 314.4 is not required where attic access is required by Section R807.1 and where the space is