Crawl Space Questions - Building & Construction - DIY Chatroom Home Improvement Forum

Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Building & Construction


Thread Tools Display Modes
Old 12-23-2011, 10:18 PM   #1
Join Date: Aug 2009
Posts: 147
Rewards Points: 75

Crawl Space Questions

I'm in the process of finishing a section of my basement to turn it into a home office. This house was built in 1959 and about 10 or so years ago had an extension added to it. The extension is a family room and master bedroom. The family room on the lower level sits atop a vented crawl space. I say 'vented' because it has two small grate vents that are embedded in the block foundation of the crawl space.

In a corner of the basement that adjoins the crawl space (i.e., the original house basement) is a ~3 foot wide x 2 foot tall rectangular access cut out of the poured concrete foundation that leads to the addition's crawl space. Based on the metal frame that is in it, I'm guessing that it is just what was originally a well window frame where they took the original window out once the addition/crawl space was put in.

My questions:

a. Since the crawl space has the two small vents, one on each side of it, in the winter it lets in a lot of cold air and makes the basement cold. Since I'm now finishing a portion of the basement (it will be insulated), I'd like to cover up the access to the crawl space to block the cold air from coming into the basement.

b. Currently, the crawl space is uninsulated. The family room that sits above it is always colder than the rest of the house in the winter. There are two ducts running heat/AC from the basement to through the crawl space to vents feeding the family room, but with a constant, unfettered stream of cold air coming into the crawl space via the vents it makes for a very cold crawl space in the winter and thus a cold floor (doesn't help that the floor is laminate wood!). I did some reading and it sounds like the way to help with this would be to put bat insulation on the floor joists in the crawl space, with the paper side 'up' against the underside of the floor, and also to lay down 6 mil plastic along the entire floor of the crawl space. While I'm a bit claustrophobic and don't look forward to crawling around (the crawl space has about 3 feet of 'headroom'), this sounds doable over a weekend. Does the plan make sense?

I could snap pics if it would help.


mark2741 is offline   Reply With Quote
Old 12-23-2011, 11:20 PM   #2
Registered User
Join Date: Mar 2009
Posts: 11,730
Rewards Points: 526

I would insulate the duct work after taping or mastic on the joints to more than minimum (Code) requirements for your area. Build an insulated/weatherstriped door between spaces. Foamboard and air seal the rim joists in both addition/basement. Insulate the floor if going with vented: Amount and type depends on location. Lay plastic on dirt first:



If any ads are present below my answer or words underlined/colored, I do not condone/support/use the product or services listed/linked to, they are there without my consent.
17,000 dryer fires a year, when did you last clean the inside of the dryer near motor or the exhaust ducting?
Gary in WA is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Crawl space Insulation questions Tim Sommers Building & Construction 1 12-12-2010 11:27 PM
Whole in Crawl Space Wall? Water Problem? - Picture! donaldp General DIY Discussions 1 03-26-2010 08:52 PM
crawl space access question rocky1charle General DIY Discussions 3 01-25-2010 03:10 PM
thoughts on crawl space heating rtoni HVAC 3 09-30-2008 12:47 PM
Inadequate center support in tight crawl space 4just1don Building & Construction 5 09-28-2008 03:29 PM

Top of Page | View New Posts


Search Engine Friendly URLs by vBSEO 3.6.1