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: 8726

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

Christopher Talarico posted a discussion

Heating with Tankless Water Heater & Hydronic Air Handler vs. Gas Furnace

Hi,I've looked around online and haven't found a lot of good information on home heating with…See More
5 hours ago
Profile IconSara Sabol, Christopher Talarico and Aaren Stewart joined Home Energy Pros
8 hours ago
Hal Skinner replied to Andy Gostisha's discussion Disguising Ductless Heat Pump Units
"Hi Andy. The bare metal units on a roof stick out like a sore thumb .  Coating them with our…"
8 hours ago
Paul Morin replied to Stephen Standley's discussion Which reading is more reliable on a Minneapolis Duct Blaster?
"Sorry for chiming in so late.  Sean’s comment early on in the discussion was the closest…"
11 hours ago
jerry gentile posted a status
"hello- anyone challenge the written QCI exam?"
14 hours ago
Kevin Jordan posted photos
19 hours ago
Susan E. Buchan's event was featured

EEBA Excellence in Building Conference at Doubletree Union Station Hotel

September 23, 2014 at 8am to September 25, 2014 at 2pm
yesterday
Susan E. Buchan posted an event

EEBA Excellence in Building Conference at Doubletree Union Station Hotel

September 23, 2014 at 8am to September 25, 2014 at 2pm
yesterday

© 2014   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service