Hey all,

We recently hired a new tech that has previously done a bunch of Home Performance work on the East coast and he has turned me on to a new idea on how to insulate a basement rim joist that is enclosed with a ceiling. I wanted to see what everyone thinks about dense pack cellulose in an enclosed rim joist.

It makes sense that when you have a joist running parallel to the foundation wall that you can drill a hole in the ceiling and fill the joist cavity that is up against the rim. But for the side of the basement that has a wall perpendicular to the joists, can this work?

I have not heard about any contractors here in Portland OR using this technique, but in my mind it seems possible. I just wanted to make sure before we do the install, that it will pass program QC. Before I present it to the program, I wanted to hear some opinions from people that have experience  using this method.

So here's how I see it. If you drill the hole about 2 -3 feet away from the rim joist (towards the inside of the basement) in the basement ceiling, and blow material into the cavity, you should be able to make sure that the rim is fully insulated. I can imagine that the material would taper towards the hole, but as long as you pack it in, it would be fine.

Thanks!

Views: 2784

Reply to This

Replies to This Discussion

Other approved materials are allowed only in section 4 of R302.11 (above), for around mechanical penetrations, not for draftstopping or firestopping in concealed frame cavities.

I was referring to the concealed cavities where codes have required nominal 2" lumber, and where dense-pack cellulose can meet or exceed the same standard.

 

R302.11.1 Fireblocking materials.

Except as provided in Section R302.11, Item 4, fireblocking shall consist of the following materials.

    1. Two-inch (51 mm) nominal lumber.

    2. Two thicknesses of 1-inch (25.4 mm) nominal lumber with broken lap joints.

    3. One thickness of 23/32-inch (18.3 mm) wood structural panels with joints backed by 23/32-inch (18.3 mm) wood structural panels.

    4. One thickness of 3/4-inch (19.1 mm) particleboard with joints backed by 3/4-inch (19.1 mm) particleboard.

    5. One-half-inch (12.7 mm) gypsum board.

    6. One-quarter-inch (6.4 mm) cement-based millboard.

    7. Batts or blankets of mineral wool or glass fiber or other approved materials installed in such a manner as to be securely retained in place.

    8. Cellulose insulation installed as tested for the specific application.

It would be great if someone did a video and u-tubed it.

 

Practically speaking, we seal all holes less than about 2' with foam.  1/2" OSB does the rest.  We foam gypsum common wall gaps at framing, gaps between double walls, and most items.  Average house will have 3-4 places where a piece of wood is used.  

Then you're not complying with code.

In what way are we not complying with the code?
In what way are we not complying with the code?
In what way are we not complying with the code?

See R302.11.1 above.

can you be specific - I am not seeing it

"we seal all holes less than about 2' with foam.  1/2" OSB does the rest"

How is that consistent with the very specific list of allowed fireblocking materials?

And, did you mean holes less than 2 feet? Even if you meant 2 inches, that still exceeds what you reported as the maximum span for foam: not span more than 1-5/16"

Something is screwy with the site tonight

We use OSB to cover the edges of things like soffits then seal with foam, and use extruded styrofoam to seal the tops for energy,  We use the foam to cover the backs of kneewalls, and use it to fabricate top and bottom plates as necessary,  No one says anything at 2" even though the es says 1-5/16 - as they realize what the material is.  We will do this as we seal over 2500 new houses in 2012 in, as I said, 500 jurisdictions (New Jersey has a jurisdiction every couple of miles)

We have excellent working relationships with most of the inspectors that we deal with.  Based on this experience, I have no qualms about using this same system in existing houses, even though the code does not apply for the level of work we are usually doing in retrofits.

Wow thanks for all the advice! I think this is enough info to prove that this is a valid strategy.

RSS

Videos

  • Add Videos
  • View All

Twitter

Latest Activity

Amber Vignieri posted a blog post
1 hour ago
Evan Mills posted a blog post

Looking Back and Looking Forward: Home Energy Pros at 5 and 5000

Over the past five years, the Home Energy Pros social network has grown from a twinkle in our eyes…See More
3 hours ago
tedkidd replied to Diane Chojnowski's discussion Poll: How confident do you feel about the future of home performance?
"Thank you for sharing this trend! Full disclosure, I did NOT ask Bob to post that! If you have 2…"
3 hours ago
Bob Blanchette replied to Diane Chojnowski's discussion Poll: How confident do you feel about the future of home performance?
"I see fixed monthly grid charges continuing to increase while cost per therm/kwh/gallon remain…"
3 hours ago
Quinn Korzeniecki posted a discussion

Vent Cap Systems and SENSIT Technologies Products Added to BPI Product List

The Building Performance Institute, Inc. (BPI) has recognized four new products in its …See More
6 hours ago
Simon joined Diane Chojnowski's group
Thumbnail

Online Training

Online training coursesIf you provide ongoing online training for home performance or…See More
yesterday
Simon added a discussion to the group Energy Auditing Equipment for Sale, Trade or to Purchase
Thumbnail

Wanted - Blower and door frame kit for Minneapolis system

Hi everyone,I'm new to this line of work and have bought some equipment (Minneapolis blower door…See More
yesterday
Simon replied to Steve Mann's discussion TEC Blower Door Frame in the group Energy Auditing Equipment for Sale, Trade or to Purchase
"Hi, I'm interested, but could you send to UK?,I'd pay shipping of course. My email is :-…"
yesterday

© 2016   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service