Subscribe or Renew Membership Subscribe Renew

spray foam code

user-5432510's picture

I realize all municipalities are different but- anyone run into code issues on insulation on reno work? Being told by 1 of 3 vendors pricing the job that if a building is taken down to the studs, the insulation needs to be brought up to code on the entire structure. Not unreasonable however the only way to get old 2x4 exterior stud walls up to R21 it would require closed cell application in them. I checked chapter 26 in 2015 IBC and didnt see where this was ref'd so could be a local thing (update NY). Anyone run into this before? I will likely need to follow up with the code office. 

Actually, it's generally (post #212568, reply #1 of 9)

Actually, it's generally quite practical to build a new studwall just inside the outer wall, to produce a 7-inch space for the insulation.  Or the new studs can (with slighly more effort) be inset to produce a thinner wall.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

R values down south are (post #212568, reply #2 of 9)

R values down south are different then what your required but yes. Our city uses a basic 30% rule, if the renovation exceeds 30% of the home value then all aspects of the home can be required to be brought up to minimum standards.

 

Definetly a question for your building inspector. 

Actually, that is not (post #212568, reply #3 of 9)

Actually, that is not practical at all; particularly with renovation work. Building a double stud wall in order to gain additional  R-value presents all sorts of expensive (if not impossible) consequences such as circulation clearances, door swing issues, window trim issues, electrical fixture issues, plumbing fixture issues, etc. in existing, conventionally framed homes.

In fact, my question to you, Dan, is when have you actually done this and had it be practical?

Hell may freeze over... (post #212568, reply #4 of 9)

i agree...

I've added 2x4 walls to (post #212568, reply #5 of 9)

I've added 2x4 walls to existing exterior walls twice.  In each case, it was a complete strip of walls in order to upgrade insulation and help straighten and plumb walls in older houses. Granted, both times I rewired completly, so there were no electrical issues, was able to staple new wires to the inside of existing wall so did not have to do any drilling.  Only exterior doors will be affected, and the extra deep resulting doorjamb just meant that the door would swing in only about 190 degrees, which was fine.  The deep windowsills are a great bonus.  I try to stagger the new studs so that are not in line with the old ones to prevent thermal bridging., and used fiberglass both times.  I'm also in  far northern ny, but there's little code enforcement in my neighborhood.

There are other options though.  You could place rigid insulation inside of your walls to gain r value, just use longer screws to drywall, or you could pack out your studs by 2 inches in order to make a 2 x 6 wall and reinsulate.  You might be able to use box entenders for your electrical boxes, not sure.

Good luck

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bonus (post #212568, reply #6 of 9)

user-3014192 wrote:

 Only exterior doors will be affected, and the extra deep resulting doorjamb just meant that the door would swing in only about 190 degrees, which was fine. 

Wow. You "only" got 190 swing out of your doors? Sounds like an unexplicatable bonus from your wall pad ins. Seems like a gut would have you resetting doors with hinge barrels inside of new drywall plane regardless of wall framing pad outs. But getting an extra 10-15 degrees of swing with your project sounds like a miracle. Most folks hit at 170-175 degrees on account of lockset for a door that is in-plane with entry wall. Anyhow, I'd like to see that detail in plan view so I can offer it to some of my clients; especially the ones that like to "go to 11" as they say in Spinal Tap.

Should have said 100 degrees, (post #212568, reply #7 of 9)

Should have said 100 degrees, or 10 degrees past 90.  Still works fine .  You're a bit on the snarky side eh?

pot calling the kettle black (post #212568, reply #9 of 9)

, or 20 degrees past 80, or 30 degrees past 70....or even 90 degrees past 10.  All would have worked fine to convey 100 degrees; not 190.

But you didn't.

Hey!  You guys know better (post #212568, reply #8 of 9)

Hey!  You guys know better than this!!

There should be no discussion of The Spray Foam Code without first getting the secret handshake!


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville