Documenting my attempt to cut my energy usage in half.

Saturday, January 14, 2012

Crawlspace Insulation Fail

I recently did a full survey of all the insulation in my crawlspace. I've been under the house on several occasions before but I never really looked at the insulation other than to say "yep, there's some there."

I'm not really sure what inspectors look for before signing off on the different phases of construction, but I have a feeling that when it comes to insulation and crawlspaces, the inspectors just ask the contractor if they insulated the crawlspace and if the contractor says yes, then it passes inspection.

Armed with a flash light and camera I dove in to see what I would find.  Below are a few of the flaws/shortcuts that the contractor took. 

On the north side of the house, there is a just a partial floor joist bay between the band joist and the first floor joist.  Since this is an odd size the easiest thing to do is not install any insulation.

Whenever there are pipes in the way, obviously the best thing to do is to push all of the insulation to one side. 

When you encounter duct work, you must not install any insulation above it.  No one is ever gonna look up there anyway, right?  And when you do put a section of insulation in, you should grab a piece that's 16" wide even though the engineered joists are on 19.2" centers. 

When you get to the end of a roll and you're 12-14 inches short of making it to the end of the joist bay, it's probably good enough.   On the east side of the house, every single bay was short by about a foot.  Lovely...

On the left side of this picture the exterior wall makes a 45 degree turn and runs right into "it's Miller time".  The end result is a three foot gap.  Notice that the insulation isn't pushed up tight against the sub floor either.  This allows cold air to get another 6-8 feet further in before it finds an insulation hanger that is properly installed.

1 comment:

  1. To take the chill out of a crawl space, it's usually best to insulate the exterior masonry walls rather than the underside of the floor above. That's especially true when heating ducts or pipes pass through the space. Unless there are excessive moisture problems in the crawl space, use unfaced fiberglass batts to insulate the walls; be sure to wear a long-sleeved shirt, gloves, eye protection, and a dust mask when handling the itchy stuff.