Crawlspace air sealing vapor retarder questions

I’m training and researching crawlspace insulation/moisture control and confused about something…

In a vented crawlspace, most common in my area (Rocky Mountains) in non-new construction, what is the suggested proper installation of vapor diffusion retarders? Should they be continuous, with sealed seams and lapped 6 inches up the walls? Or does that only apply to non-vented crawlspaces?

Would you always recommend fully air sealing, insulating and closing vents in a crawlspace in a climate that has long winters and reasonably moderate summers (low humidity and temps rarely over 90)?

This will also help me distinguish between a defect and an FYI item to improve moisture control and thermal efficiency.

To start, a defect is something that is broken or does not function as intended.

If a house has ventilation, no insulation, or what ever when built, it is not your job to recommend anything about making it better in accordance with today’s standards. A crawl space requires ventilation to control moisture, not about what the weather is outdoors. Efficiency is not in your in the scope of your job. How are you going to determine the year long conditions of a crawlspace during a 2hr visit to the house? If there is a defect because something is not installed correctly then you are associating it with something that is actually going on, not something that might happen if the future.

For every action, there is an opposite and potential adverse reaction. You address this perceived situation because of energy efficiency and you can cause an unhealthy condition detrimental to the occupant. High fuel bills are not detrimental. Mold, Rot, Radon, are. Do not base your recommendations on International practices. If you do not see a visible defect (which is what your job is as a HI) do not make recommendations on things that are not your job. There are people out there that evaluate and mitigate these conditions and make recommendations based on factual testing. By SOP you are only allowed to go beyond the HI SOP if your trained, licensed, or otherwise qualified to do that job. A NACHI on line course is not generally sufficient, nor intended to be.

As a HI you are there to Observe, Document, and Report what you see and test. If you see a defect, it’s a defect. If you turn something on and it does not respond, it’s a defect.

FYI’s are for when the client asks or is concerned specifically about a system.
A 1957 Chevy is a 57 Chevy. Your not there to recommend an upgrade to make it something else unless asked for your opinion.

Keep this in mind as you grow into this business.
You want to do good in this business. Consider everyone involved in the purchase or like you read here all the time, conflicts will arise with Agents and Sellers which is toxic to the growth of your business. I’m not talking about writing soft reports, I’m saying, keep things in perspective for what they are. Your an educator, not the house police.

Welcome, and good luck. This is just an opinion for your consideration

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Post where it says so in any HI SOP.

I’m addressing resale homes, not new construction.
I’m talking about report defects, not verbal opinions.

This is not about what you ‘can’t’ do, it’s about if you want to succeed in this business. This is a new guy. What he puts in his reports will determine his progress in this business. New guys want to outdo all you seasoned guys and always try to overdo it.

Knowing your clients expectations and meeting them will make you successful. Scaring the crap out of them with opinion doesn’t help reaching that goal.

You can do stupid stuff all day long, I’m not taking to you.

So you never recommended GFCIs be put in into 1950s home being resold. Like I said, bullsh*t. If anything, you confused the “new” guy. I don’t, really, understand why you do this at times.


Thank you for your opinion but it seems to go counter to a lot of the interNACHI training…

Thats what I always recommend.

I make no recomendations as it’s not part of the SOP. But I do inspect for proper ventilation along with lack of insulation or describe insulation.