Treating crawl spaces (with ductwork) when the adjacent basement ceiling is insulated.
I am currently speaking with a homeowner who would like to replace the existing FG batt insulation in the ceiling above his crawl space. The crawl is connected to the basement, and the basement ceiling is insulated with FG batts as well. The crawl has ducts insulated to R-4.2 throughout it. The crawl floor is a thin layer of concrete (about 1").
I spoke to him of two options:
1. Slap R-19 un-faced FG batts in the ceiling, and then slap 1/2" to 1" of foil-faced rigid foam to the underside of the floor joists.
OR
2. (This is my preference). Lay down 6-mil poly across the floor of the crawl, and adhere the poly to the crawl walls (up a couple of feet). Then install 2" of foil-faced rigid foam to the crawl walls.
I will also be insulating the rim\band joists throughout the basement.
Any advice?
Views: 146
Replies to This Discussion
-
Permalink Reply by Timothy Renz on -
I agree with your preferred option. If the connected space is climate controlled then stopping moisture and outside air from entering is the best option. Only putting the FG batts in the ceiling of the crawl space would still leave the influx of air to deal with and it would decrease the efficiency and comfort of the home.
-
Permalink Reply by Patrick Michaelyan on -
Thanks Tim. I have been pushing this option, and I think the homeowner is going to bite.
-
Permalink Reply by Glen Gallo on -
I would suggest a true vapor barrier product or ASTM E-1745
From my short education on the product you want to make sure that the product is rated for the application. It is critical that the product is mechanically fastened to the wall and sealed. If there are any piers the product should be fastened and sealed to it as well.All seams sealed with tape approved for the product
I use 1x2 and ramset for fastening and duct mastic for sealing.
It is tedious, boring and often unappreciated in a challenging space.
I would always be concerned about the walls ability to dry. If the outside stem wall is buried I would think twice before insulating it
-
Permalink Reply by Patrick Michaelyan on
-
That is some really valuable input Glen. I definitely will continue to think this one through.
Thanks.
Patrick
Home Energy Pros
Home Energy Pros was founded by the developers of Home Energy Saver Pro (sponsored by the U.S. Department of Energy, under the American Recovery and Reinvestment Act) and brought to you in partnership with Home Energy magazine.
Latest Activity
Tom Mallard just added their location.
Meagan Foster posted eventsHomes 401: Green Rater Training
August 15, 2013 to August 16, 2013BPI Building Analyst Field Training
September 9, 2013 to September 12, 2013BPI Building Analyst Field Training
July 15, 2013 to July 18, 2013
Meagan Foster updated an eventEnergyLogic's RaterFest! at Black Hawk, CO
September 13, 2013 at 10am to September 15, 2013 at 12pm
Join us for one of the best home energy conferences available! This retreat will provide…See More
Meagan Foster updated an eventHomes 401: Green Rater Training at Berthoud, CO
June 25, 2013 to June 26, 2013
This highly interactive workshop builds upon the material presented in the online course, further…See More
Meagan Foster updated an eventHERS Rater Training - Online at Online
July 1, 2013 to July 26, 2013
NEW - our great RESNET HERS Rater online training is now completely self-paced, so you can start at…See More
Meagan Foster updated an eventBPI Building Analyst Training - Online at Online
June 3, 2013 to June 28, 2013
Join the EnergyLogic Academy for our BPI BA online training - we just went to a completely open…See More
Anna Svensson posted a discussionLooking for residential building and remodeling experts
Making sure you residential building and remodeling professionals out there are aware of the call…See More
Bryce Cramer joined Leslie McDowell, BPI's group
Building Performance Institute (BPI)
BPI is the nation's premier standards development, quality assurance and credentialing organization…See More
Bryce Cramer replied to Mike Kandel's discussion June's Stump the Chump: What's Wrong with this Picture? in the group Building Performance Institute (BPI)"Key is this was done in warm weather. The back wall of the room was also uninsulated, but the lower…"
James Hatheway added a discussion to the group Job Board
Quality Assurance Verification Specialist - Little Rock, Arkansas
CLEAResult (clearesult.com) is looking for a QA Verification professional who wants to leverage…See More
© 2013 Created by Lawrence Berkeley National Laboratory.
