| Author |
Message |
W. Dean Walker
New member
Username: wdwalkerspecs
Post Number: 1
Registered: 08-2006
| | Posted on Thursday, April 12, 2007 - 09:14 pm: |    |
Have you ever encountered a product that can be applied to a ground surface that acts as a vapor retarder? I don't think my client wants visqueen. I think he is hoping of a liquid of some sort. Project in in TX. |
Ronald L. Geren, RA, CSI, CCS, CCCA, SCIP
Senior Member
Username: specman
Post Number: 439
Registered: 03-2003
| | Posted on Thursday, April 12, 2007 - 11:43 pm: | |
There's Liquid Boot used for gas vapor barriers, which could work.
Have you thought about a liquid-applied vapor retarder sprayed on the underside of the floor system?
(BTW, I hope you're not using "Visqueen" as a vapor retarder under concrete slabs) |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 356
Registered: 05-2003
| | Posted on Friday, April 13, 2007 - 03:26 am: | |
Stego Products: http://www.stegoindustries.com/ |
W. Dean Walker, AIA, CCS, SCIP
Junior Member
Username: wdwalkerspecs
Post Number: 2
Registered: 08-2006
| | Posted on Friday, April 13, 2007 - 11:00 am: | |
The word is "liquid". Last time I checked Stego only had sheets.
This is the quote from my client:
"Believe it or not, the IBC 2003 code requires it for crawl spaces or we have to increase or areaways significantly".
No I don't specify "visqueen". I use the term to describe sheet vapor retarders in general. |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 357
Registered: 05-2003
| | Posted on Friday, April 13, 2007 - 11:23 am: | |
How are going to apply a liquid to the ground -maybe to the underside of the floor system? |
Ronald L. Geren, RA, CSI, CCS, CCCA, SCIP
Senior Member
Username: specman
Post Number: 440
Registered: 03-2003
| | Posted on Friday, April 13, 2007 - 11:34 am: | |
Dean:
The vapor retarder is only required in two of the exceptions to the provisions for underfloor ventilation. If you provide sufficient openings, no vapor retarder is required. (Ref. 2003 IBC Sections 1203.3.1 and 1203.3.2) |
W. Dean Walker, AIA, CCS, SCIP
Member
Username: wdwalkerspecs
Post Number: 3
Registered: 08-2006
| | Posted on Friday, April 13, 2007 - 11:43 am: | |
Ron: Thank you for the positive response. I don't have a copy of the code and am relying on my client's interpretations.
Also, Liquid Boot is a possibility.
I've been a specifier for over 40 years and am often stumped. From now on I know where to get answers. |
Ronald L. Geren, RA, CSI, CCS, CCCA, SCIP
Senior Member
Username: specman
Post Number: 441
Registered: 03-2003
| | Posted on Friday, April 13, 2007 - 11:53 am: | |
Dean:
Here's the actual text for the references I listed above:
1203.3.1 Openings for under-floor ventilation. The minimum net area of ventilation openings shall not be less than 1 square foot for each 150 square feet (0.67 m2 for each 100 m2) of crawl-space area. Ventilation openings shall be covered for their height and width with any of the following materials, provided that the least dimension of the covering shall not exceed 1/4 inch (6 mm):
1. Perforated sheet metal plates not less than 0.070 inch (1.8 mm) thick.
2. Expanded sheet metal plates not less than 0.047 inch (1.2 mm) thick.
3. Cast-iron grills or gratings.
4. Extruded load-bearing vents.
5. Hardware cloth of 0.035 inch (0.89 mm) wire or heavier.
6. Corrosion-resistant wire mesh, with the least dimension not exceeding 1/8 inch (3.2 mm).
1203.3.2 Exceptions. The following are exceptions to Sections 1203.3 and 1203.3.1:
1. Where warranted by climatic conditions, ventilation openings to the outdoors are not required if ventilation openings to the interior are provided.
2. The total area of ventilation openings is permitted to be reduced to 1/1,500 of the under-floor area where the ground surface is treated with an approved vapor retarder material and the required openings are placed so as to provide cross ventilation of the space. The installation of operable louvers shall not be prohibited.
3. Ventilation openings are not required where continuously operated mechanical ventilation is provided at a rate of 1.0 cubic foot per minute (cfm) for each 50 square feet (1.02 L/s for each 10 m2) of crawl-space floor area and the ground surface is covered with an approved vapor retarder.
4. Ventilation openings are not required when the ground surface is covered with an approved vapor retarder, the perimeter walls are insulated and the spaceis conditioned in accordance with the International Energy Conservation Code.
5. For buildings in flood hazard areas as established in Section 1612.3, the openings for under-floor ventilation shall be deemed as meeting the flood opening requirements of ASCE 24 provided that the ventilation openings are designed and installed in accordance with ASCE 24. |
Harold S. Woolard
Senior Member
Username: harold_woolard
Post Number: 48
Registered: 12-2003
| | Posted on Friday, April 13, 2007 - 04:44 pm: | |
Mr. Walker Email me back and I will tell you of a product that I represent that has been used in crawl spaces in the Houston, TX area, and why it the simplist system to use. Don't get roped in with the roll good ASTM 1745 materials. This system is liquid. hswool@consolidated.net |
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