Ecobuilder,

I've looked at those paints and was thinking about using one on the exposed areas in my attic (even though the ES reports for my spray foam says that it isn't required).  Probably better to use that paint in the kitchen or around the electrical panel.  I was amazed at the ES reports on the paint.  I didn't think it was very expensive as compared to drywall or other barriers.  I have no idea why it hasn't been adopted as the primer coat of any room having a woodstove/fireplace, for every ceiling with living space above, etc.  Actually, I do have an idea.  The paint doesn't come with a label that shows an inspector that it has been properly applied.  The AHJ will reason that an unscrupulous owner or builder might just use white paint and save $50.  If it can't be easily verified by the inspector, it can't be required.  Still, an amazing product for those who want to build beyond code minimum.

Greg,

I am an attorney.  So is my wife.   They know it.  That's probably why I haven't just been shut down already.  I've asked that any further determinations be in writing, so they know where this is going.

Too soon for taking a political route.  I think I'll let the permit process take its course.  I have, however, thought about spraying the insulation, and finishing the house.  I could take pictures of everything or, better yet, call for a private inspection.  My local building inspectors aren't state licensed.  There are licensed inspectors that can be hired to file reports of compliance.  I had to hire one of a previous project when I got red tagged.  The inspectors couldn't or wouldn't understand the engineering.  I hired a private inspector to watch the installation, sign off on it, and file a report.  I then proceeded.  Never heard anything from the county.

The latest silliness involves the terminology "unvented attic;" specifically what is an attic.  My AHJ says that the "space" above my bedrooms is an attic, but the sloped ceiling area is not.  He then maintains that the code provision in IRC R806.4 permits unvented attics but not unvented sloped ceiling areas.  Although I've never gotten a direct answer, I think that his reading of the code requires that I vent that area even though SPF insulation doesn't require ventilation.  I can't vent that section of the roof into the unvented attic above, of course, as there is no ventilation above.  So it would require soffit vents and then roof vents halfway up the roof on every rafter bay.  Can anyone really believe that this is what the code writers had in mind when they authorized the use of spray foam insulation on the underside of roof sheathing without any ventilation?

The code actually defines an attic as the "unfinished space" between the roof rafters and the ceiling joists.  Yet the code requires the attic to be finished with a thermal barrier if it is occupied space or storage.  So, if you finish an attic as per code requirement, it is not an attic as per code definition.  Or could that simply be an inconsistancy in the code?  An inconsistancy would require common sense by the AHJ to determine the intent of the code and reconcile the sections.   When pigs fly. 

The silliness gets better if you only see attic space as that in a typical mid-century U.S. tract home.  That's the "regular" attic that collects cobwebs, dust, Christmas decorations, etc.  A vaulted or cathedral ceiling may not have this space, and if "space" is the definition of an attic, then unvented attics "spaces" are allowed, but unvented cathedralized ceilings using the exact same construction technique are not allowed.  There's no justification for "space" (ventilation) in an unvented attic, but if there isn't space, then it isn't an attic and can't be permitted as an unvented attic.  Follow that?  Is it another inconsistancy or is it supported by sound building science?

If attics can be finished (as I believe), I think the code specifically allows my request for an unvented roof.  My bedrooms have a kneewall, a sloped ceiling following the roofline, and collar ties that form a flat section at the peak.  The common terminology for this design is an "attic bedroom."  Very, very common in older homes in Europe, which is the basis for my house design.   Attic bedrooms were the norm in smaller homes.  Attic bedrooms are not neccesarily remodels of an attic (although they sometimes are in the U.S.).  The sloping ceiling is not something separate from an attic bedroom, it is integral to the attic bedroom.  Without it, you don't have an attic bedroom.  I'm going to finish the ceiling of my attic bedrooms with 5/8th inch drywall thermal barrier as required by code.  I've chosen to construct my attic bedrooms with an unvented attic system as allowed under R806.4. 

So ignoring any issues of building science and code intent (which the county has yet to address), we know this from the code:
1)  unvented attics are permited.
2)  attics must be finished with a thermal barrier in occupied areas.
3)  attic bedrooms are occupied areas.
4)  unvented attic bedrooms are permitted if finished with a thermal barrier.
That may be waaaaaaay too logical.  I can feel the push-back already.

Right now, I'm waiting on an answer to why the unvented roof section of my attic bedroom is not an unvented attic.   I've also asked for all of the code provisions that require venting an unvented attic.  I have the burden of proof in showing that my design meets or exceeds code.  But before I can do that, I need to know where and why the county thinks the design does not meet code.  We'll see.

Mark

I'm sitting at home right now, so I've got plenty of time.

As to proving to the building inspector that the product was applied. Keep your invoice and the empty containers for him to see. If he still doesn't beleive you then he is a *#@. Why is it that building inspectors make it hard for us to build better buildings. I think it is because they don't know enough about them and are a little intimidated by them. Before wide spread green building practices can be achived the officials overseeing them need to be better educated, maybe all building inspectors should be LEED certified. Either way, at this point they seem to just put road blocks in the way that make the process much more difficult than it has to be. I think I spent more time educate the inspectors on my current project than they spent inspecting the building. 

Tom pittsley 

I finally got permission.  So that's three times "yes" and two times "no."  Right now was a "yes" period, so I had it foamed.  I think that when I asked for the AHJ's reasoning in writing so that I could appeal the decision, that had some effect.  It only took three months to get there. 

So now what can go wrong?  Stuff did.  I'm not going to post about in until after I have my certificate of occupancy.  The foam installers are their own worst enemy.  Grrrrrrr.

Mark