How to Inspect the Attic, Insulation, Ventilation and Interior Course

This thread is dedicated exclusively for those students currently enrolled in the InterNACHI course titled, “How to Inspect the Attic, Insulation, Ventilation and Interior” course located at

Students are free to pose questions and comments here and join in the conversation with other students. The thread will be monitored by the course instructor.

Contact: Director of Education, Ben Gromicko

Thank you.


I recently inspected a 35 year old cottage with a nicely maintained, wood framed and sided exterior. When I walked into the house with the buyer, I noticed unfinished drywall and some plastic sheeting covering insulated exterior walls and asked the buyer if they were doing some remodeling. His reply was “no, the owner (original & current) did all the finish work and this is as far as he has gotten”. I was shocked!
The buyer didn’t seem to concerned about taking over from this point but I did express concern over the apparent lack of AHJ involvement in this finish process, particularly with the electrical wiring that was still visible and, the potential defects already covered up.
As I was reading through the Vapor Diffusion Retarder Section of this required course (thank you for the reminder and your new system of listing what we have and have not taken), I noted the big difference on the perm rating of unfinished and finished drywall on the attached table.
I got to thinking about the possible deterioration of the core of this unfinished drywall with a vapor barrier backing at areas that may have been exposed to cold temperatures while the interior was heated, creating moisture saturation on the back of the drywall. Any thoughts?

Perm ratings.jpg


Ben, I was a little confused by the section on Vapor Diffusion Retarder vs Vapor Barrier. In the text it says “they are not exactly the same thing” then it goes onto say, “A vapor barrier, as defined by the International Building Code (IBC), is classified as 1 perm or less”. At the end of the paragraph it says “The 2006 International Residential Code (IRC) defines a vapor diffusion retarder as a material, membrane or covering, such as foil, plastic sheeting or insulation facing, having a rating of 1 perm or less”

Am I missing something?

This link may help in explaining.

Thanks Marcel, This article helped a lot.

So they are the same but they changed the name of Vapour Barrier because it was more misleading that the term Vapour Diffusion Retarder, either way they have a perm of < 1.

I’d just got used to calling it Vapour Barrier after 20 years in the U.K calling it either a DPM or DPC (damp-proof membrane, damp-proof course) which had to be completely waterproof.

Can we leave the name the same for a few years now please? Pretty please…

No problem here. :wink:

One of the ways in which American English and British English differ is in spelling.

A good friend of mine was a Brit., his name was Gerry Beaumont.
We named an Award after him.

Can I have one too? :slight_smile:

Sure, just go here and follow the guidelines.

Going to be starting this course.

Definitely one to add to the list, I’m still about 50 shy of my GB award this year! Shocking! I need to roll up my sleeves. (I already have about 50 planned)
Len, I have for now given up trying to think about homes in the UK, my sister was blethering about some rafter the other day, I had no idea what she was on about! Whatever it was, she needs a new one! LOL.

I have just completed this course and am headed towards the exam.
Many interesting information in this course. I need to insulate my attic!:slight_smile:

In the usually rare event the NC sensors are somewhere between the 1"-2" mark above the floor. What would be an acceptable method for placing the 2x4 in the path of the door for the Contact Reversal test?

Would it be acceptable to raise the 2x4 above the NC sensors “Line of Sight” by placing a small block under each end of the 2x4?

I have only seen NC sensors that low once, usually they are somewhere in the 2.5" to 6" range.

starting course

Ben, I also want to thank you for setting up the auto warning system. With everything going on trying to get a business up and profitable as well as working a demanding day job, and taking care of several inlaw famlies that are mechanically challanged, it’s easy to slip on remembering everything. Starting the Ventalation course now.

Ben, I have a question on the certificates for this class. According to the class info (in a couple of places) this is a Texas approved course. However, once you finish the test, there isn’t a TREC approved certificate to print out. Hopefully, this is just an oversight.

Thank you in advance.

Just starting this class. It is a long one. I am sure it will refresh much of my knowledge and hopefully give me some new information.:slight_smile:

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why am I not allowed to continue this course?

In the “Student Verification” slide, you must click the link that takes you to this forum (which you’ve done).
Close this window or tab.
Go back to the course, and click “Next.”

That should do it.

Starting now