Community: Building Code Questions

Much of the value of this site is the pooled experience of members and their willingness to share it. This page offers a Community area formatted for Questions & Answers dedicated to Building Code Questions. Other topics appear to the right.

Anyone may ask a question and anyone may answer. Sometimes one of our 15 Advisors may chime in; in other cases, you'll get the wisdom of some of our members who have some experience in this area. We encourage everyone to give us the benefit of both their questions and answers. The usual rules of courtesy apply.

Does green building seem to be at odds with the code?

Please encourage your building inspector to come here and participate in this Code Q&A; in the meantime, jump in with your experiences -- both positive and negative.

Each week, one lucky question will be chosen for an in-depth answer by Lynn Underwood, CBO of Norfolk, VA and posted in the Code Green blog.

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5 Answers
Convincing a code official about location of Vapor Retarder

So I am working with a client renovating their attic space for a master bedroom. The existing knee walls has kraft face batt insulation with no sheathing of any kind on the attic side of the wall. Which we all know renders the batt insulation useless.I am proposing to install 2" of foil faced polyiso on the attic side. I am able to find the Legacy report from the manufacturer stating it can be left exposed in these types of conditions. And I was just reading the Q&A about the Correct use of foam insulation.

Asked By Joshua Lloyd | Mar 5 10
12 Answers
A statement from Icynene

Those following the spirited discussion that followed the posting of "It's OK To Skimp On Insulation" may be interested to learn that a senior representative from Icynene has posted a response.

Paul Duffy, Icynene's vice president for engineering, posted his response today (Feb. 11 at 1:52 pm). Find it here:
http://www.greenbuildingadvisor.com/blogs/dept/musings/it-s-ok-skimp-ins...

Asked By Martin Holladay | Feb 11 10
3 Answers
Is bubble wrap duct insulation Energy Star approved, and is it a good idea?

I spoke with a HVAC installer who said he wanted to insulate my ducts with double-wrapped bubble wrap as a cheaper way to achieve R6. Does this stuff really work and would it be Energy Star and/or ACCA Manual D approved? Would there be new problems created? I have never seen it done.

Thanks

Asked By Lora | Feb 17 10
9 Answers
Don't Ask .... Don't Tell

I recently read a TROUBLESOME comment by Li Ling Young in Martin's "OK to Skimp" blog: http://www.greenbuildingadvisor.com/blogs/dept/musings/it-s-ok-skimp-ins...

Li Ling (on 2/6/10) brought up an important CODE Safety question....
Is it possible that the building code may NOT allow uncovered spray foam installations beyond 5 or 6 inches thick?
Is this true?
How can this be true?

Asked By John Brooks | Feb 19 10
2 Answers
HERS rating and new Energy Codes

I have attended several new building code seminars here in Massachusetts that discuss the implications of the 2009 IECC Code as part of the 2008 Green Communities Act. In addition, this act allows municipalities the option of setting above code energy efficiency requirements for commercial and residential projects. Labeled the 'Stretch Code' and backed by $10M in funding, this code is noted as a practical way to demonstrate life-cycle energy efficiency.

The Stretch Code employs the Home Energy Rating System (HERS) with thresholds related to home sizes.

Asked By Jon Wyman | Feb 18 10
7 Answers
Green Permits

I learned today that a couple of builders I work with "volunteered" me to meet with one of our local Codes Departments next week to explain, and possibly help develop the process for, a streamlined Green Permitting Process. While there is good information here in the Code Green Blog, I am curious if anyone else has been through this process with their Codes Department? If so, I would appreciate any comments or suggestions related to your experience.

Asked By Grant Dorris | Feb 4 10
1 Answer
Graywater system questions

I would like to build a small cottage with a composting toilet and a graywater system for the sinks and shower.
I need plans and a contractor perhaps.
Any advice when dealing with the code officer?

Asked By Matthew Walton | Feb 11 10
3 Answers
Where in the IRC 2009, Chapter 11, is the cathedral ceiling limited to 500 square feet or 20%?

I can find no reference to 20%. This requirement is, I read it, for ceilings that can't meet the specified thermal resistance and are allowed to downgrade. Obviously this limit would not apply if the ceiling is fully insulated.

Asked By Peter d'Entremont | Dec 8 09
4 Answers
Visual vs testing for air leakage in IRC '09

Hello- I am cruising through my (newly fatter) copy of IRC '09, reviewing the upcoming changes, and this one caught my eye; in Energy Efficiency, Chapter 11 N1102.4.2.1 and N1102.4.2.2. These are the options for inspection to air sealing and insulation. I get a little confused. It looks like a builder can either: 1: do his own blower door test, or hire someone to do one, or 2: have the building inspector do a visual inspection of a fairly stringent nature. In addition, it looks like the inspector can require a 3rd party visual inspection for insulation and air tightness. Hmmm.

Asked By T.C. Feick | Nov 12 09
2 Answers
What is the code-required lap joint overlap needed on a 2/12 roof?

I HAVE A 2/12 (permitted) LEAN-TO STYLE ROOF IN TAMPA, FL. JOISTS ARE 16 O.C. THEN PLYWOOD AND CLIPS, THEN 30 WEIGHT FELT PAPER WITH THE STANDARD 3 INCH LAP JOINT. FELT IS NAILED OFF 6 INCCHES O.C. ON THE LAPS, AND 12 INCHES O.C. IN THE FIELD. I PLAN ON INSTALLING 5V CRIMP 26 GAUGE METAL IN ONE PIECE FROM RIDGE PEAK TO TAIL ON BOTH SIDES OF THE ROOF. THE INSPECTOR SAID THAT HE THINKS WHAT I HAVE ON THE PRINTS WILL PROBABLY BE ALRIGHT, BUT HE NEEDS IT IN WRITING BEFORE HE CAN PASS ME. CAN YOU PLEASE SEND THE THE FL # OR SPECS THAT I NEED? THANK YOU, JON BRIGGS (407) 301-4527

Asked By JON | Nov 15 09

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