Hi There Folks,


I came across this crawlspace vapor barrier installed by a BPI contractor. 

Location:  Bay Area of California- near the ocean.  

Environmental Factors:  The area receives a lot of rain, and is notorious for rising groundwater.  

Health Factors:  The customers have respiratory issues, and these were communicated to the contractor.

Material:  6mm visqueen, red tape, nails

Concerns:  The material stops several inches short of the foundation walls. Some seams are taped with red tape.  Held to ground with 8 inch nails. 

I have a lot of respect for this particular contractor, but I have grave questions about how he approaches barrier installation in crawl spaces.

He has responded that this approach is adequate for unconditioned crawlspaces.  


I would appreciate insights, and direction to standards. 

Tags: barrier, crawl, space, vapor

Views: 9652

Attachments:

Replies to This Discussion

I am not sure what the codes say in Cali but (unless I am overlooking it) there is no requirement in the 2009 IRC or IECC for "vented" crawls

For sealed crawls it is;

R408.3.1 Exposed earth is covered with a continuous Class I vapor retarder. Joints of the vapor retarder shall overlap by 6 inches (152 mm) and shall be sealed or taped. The edges of the vapor retarder shall extend at least 6 inches (152 mm) up the stem wall and shall be attached and sealed to the stem wall;

As for the groundwater issue:

R408.6 Finished grade. The finished grade of under-floor surface may be located at the bottom of the footings; however, where there is evidence that the groundwater table can rise to within 6 inches (152 mm) of the finished floor at the building perimeter or where there is evidence that the surface water does not readily drain from the building site, the grade in the under-floor space shall be as high as the outside finished grade, unless an approved drainage system is provided.

As for best practices, especially when a respiratory issue is involved - it is basically what everyone else mentioned - run up the foundation wall a minimum of 6", joints lapped lapped, and every hole, seam, etc... should be taped & sealed per manufacturers directions

RSS

Home Energy Pros

Home Energy Pros was founded by the developers of Home Energy Saver Pro (sponsored by the U.S. Department of Energy,) and brought to you in partnership with Home Energy magazine.

Latest Activity

Hannah Miller commented on Adam Flowers's blog post Comfort as a Selling Point
"Hello Adam! I hope you are still messages from this site. I just was forwarded your post and it…"
3 hours ago
Michael Dunseith replied to robert jones's discussion Should your local weatherization company be required to have someone BPI certified on their staff?
"Why the concern with airflow around heating and domestic pipes? Most are inside the envelope. What…"
5 hours ago
Tom White posted a video

Weatherization to Home Performance -- Tools & Tips for Developing For-profit Services

Are you a low income weatherization contractor looking to add home performance work you your services? The Home Performance Resource Center, Efficiency First, and NCAF present resources developed through expert industry engagement. While many of the…
7 hours ago
Jim Gunshinan posted a discussion

Tax Time Blues

There is a tax credit available to homeowners who have walls insulated. The credits were continued…See More
8 hours ago
Bruce Glanville replied to robert jones's discussion Should your local weatherization company be required to have someone BPI certified on their staff?
"I have been testing homes for my state utility as a baseline residential load data collection…"
8 hours ago
Stan Kuhn replied to Jim Gunshinan's discussion When your shower is in your kitchen...
"I think this is in the wrong Forum, it belongs in Hall of Shame.  One the dumbest ones…"
9 hours ago
Terrell posted a status
"Ebook version of my book Passive Buildings in Canada - detailed sections http://store.blurb.ca/ebooks/521524-passive-buildings-in-canada"
10 hours ago
Terrell posted an event

Boots on the Ground webinar at Toronto

March 10, 2015 all day
Passive Buildings Canada is pleased to be a sponsor and webinar host for BlueGreen Consulting…See More
10 hours ago

© 2015   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service