Community: Building Code Questions

Q & A Instructions

[Click map to enlarge]

The GBAGreenBuildingAdvisor.com web site has a wealth of articles on a wide variety of construction topics. Before posting your question, you may want to check out the articles on this page: How To Do Everything. You just might discover an article there that provides the information you seek.

Please register for a free account or sign in to ask and answer green building questions.

If you want to post a question, the usual rules of courtesy apply:
1. Be nice.
2. If you can't be nice, be polite.
3. If you can't be nice or polite — well, please be brief.

To attach a photo or illustration: Under the box labeled “More explanation,” look for the words “File attachments.” Click that, and you should be able to attach a photo.

Thanks for joining the conversation!


1 Answer

Flame Spread rated spray foam?

I heard yesterday about a new spray foam product that had a flame spread rating that met code without the application of an additional coating - Apparently it is a distinctive color so building inspectors can recognize and sign-off on it.

Does any one have any info on who is producing this product and how the pricing compares to foam with flame spread resistant paint applied after installation of the foam? Does it contain halogenated flame retardants? Is information available on what the flame retardant used is (TPP? or TCPP?)

Asked By Michael Chandler, GBA Advisor | Dec 2 16
4 Answers

Difficult building inspector

Needless to say our Building Inspector is real charmer, and on top of that is very unfamiliar with energy smart building techniques. We are putting up 3" of Roxul comfortboard followed by 1x4 furring strips and Hardiplank fiber cement siding. The inspector wants proof from James Hardie that this method is acceptable and safe. We sent him this document from Roxul where they had Building Science Corp conduct a study on deflection using our exact cladding system.

http://www.roxul.com/files/RX-NA_EN/pdf/tech%20data/110816%20Roxul%20Com...

Asked By Brian W | Nov 21 16
13 Answers

Insulation on exterior and interior

My house was built in 2009 in climate zone 6. It has a poured concrete foundation with R-5 XPS exterior insulation. Currently there is no insulation on the inside.

I am planning on finishing my basement and am curious on what the best way to insulate the interior would be. I spoke with my city inspection department and got some conflicting information on energy code compliance. One inspector advised not to add any additional insulation and the other advised 1"XPS with a 2x4 uninsulated studwall was sufficient but the XPS was not totally necessary.

Asked By Nick Collins | Nov 14 16
7 Answers

Treated or untreated top plate?

Which provides the best attachment for a top plate for a concrete core (ICF) wall?

A foam sill gasket will be used between the raw concrete and the wood top plate to provide a break.

Hearing two sides. Some claim a treated top plate provides better rot protection, especially as the concrete cures in the wall. The other side is that a treated 4x6 piece of lumber will not provide as much screw bite and remain true & straight as an untreated 4x6 Doug Fir would.

Out here the treated lumber is the brown cote lumber. It does have a tendency to split as the chemicals leach out.

Asked By Peter L | Nov 8 16
4 Answers

Does anyone know of an approved 1 hour fire rated assembly for fascia and soffit? (ICF with SIP Roof)

I am constructing an ICF house with a SIP roof which will overhang the walls. On the east side of the house (Gable side), I am within 3 feet of the property line and thus need a 1hr fire rated assembly for the fascia and soffit. I am having trouble finding an assembly from UL or elsewhere. Please help if you know.

Asked By Jordan Schiele | Nov 3 16
8 Answers

Question about adding an outlet in front of foam board insulation

I have a Brick home.
My wall consists of brick then 1x4 frame laying the flat way with 1" foam board in between. Then the entire wall covered in 1" foam board then 1/2" osb then 3/8" drywall.
I want to add an outlet below a light switch that is already installed.
There is not access in the attic and from what I can tell from the basement is the wall is 1.5" on top of the basement wall so I can't drill up through the floor.

Any suggestions would be appreciated

And I do not want to install 2x4 frame just to add an outlet

Asked By Tyler Klingbiel | Oct 16 16
3 Answers

Finishing a basement room below grade in Climate Zone 5

Hello, I have a questions regarding finishing below grade walls in zone 5. We have been researching the correct steps to finishing these walls but seem to get different answers depending on whom we ask. I went to our county and state code websites but didn't get clear answers there either. I would love to get some feedback to hopefully simplify the answers for us. Thanks for your time!
Christy W. Madison WI

1. Is it best to leave a gap between the framing and the concrete below grade wall?
2. What kind of insulation is best, Styrofoam, spray foam, etc for below grade walls?

Asked By Christen Ward | Oct 4 16
1 Answer

What is the N.C. code requirement for R-value for roof and exterior walls? How many inches of closed-cell foam is it?

What would be recommended for the R-value and inches of closed-cell foam below living space and unheated garage space ?

Asked By Daniel Mckay | Sep 17 16
5 Answers

Return air location and height

I have a vintage 1985 tract home in San Diego County, Climate Zone 3B. I am planning for a kitchen remodel, drawing plans for a permit.

The return air is located in the kitchen, the kitchen is open to the main living room, so the room volume is not a problem. The return air is located in the far corner of the kitchen. The natural gas stove is about 8 ft away from the return air inlet. By the 2012 IRC the stove should be 10 ft away. I don't/can't plan to move it to get the distance.

Asked By Tim Rudolph | Sep 7 16
11 Answers

Residential frost-protected shallow foundation in central Mass.

We are planning to provide a monolithic pour frost-protected shallow foundation (FPSF) for a single story 1300 sq ft 2 bedroom home in central MA. Air Freezing Index is 2000. I have read through many different case studies, research papers, codes, etc and there is a bit of conflicting and locale-specific info so I am looking to see whether I understand what is required here. I am a newbie owner-builder. Any constructive criticism would be appreciated, but I don't want to foment any religious wars.

Asked By Kenneth Gartner | Sep 2 16
Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!