Vapor Barrier Over Open Cell Rim Board/Floor Joist - Insulation - DIY Chatroom Home Improvement Forum
Advertisement


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Insulation

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools
Display Modes
Old 02-27-2019, 12:00 PM   #1
Newbie
 
Join Date: Sep 2018
Posts: 17
Rewards Points: 8
Default

Vapor Barrier over Open Cell Rim board/Floor joist


Hey Guys,
Long story short. My insulation contractor sprayed the wrong foam (open cell) in my house. I wanted CCSF but that is a whole 'nother issue I'm dealing with. My question, how can I effectively install a vapor barrier over where the rim board and the floor joists are. None of that foam has been trimmed, yet. Ideally, this would've been done with CCSF and voila! but wondering what solutions I have now that this is screwed up. Thanks.
Ajk2004 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 02-27-2019, 12:05 PM   #2
retired framer
 
Join Date: Jun 2017
Location: Fraser Valley BC Canada
Posts: 28,165
Rewards Points: 24,220
Default

Re: Vapor Barrier over Open Cell Rim board/Floor joist


Quote:
Originally Posted by Ajk2004 View Post
Hey Guys,
Long story short. My insulation contractor sprayed the wrong foam (open cell) in my house. I wanted CCSF but that is a whole 'nother issue I'm dealing with. My question, how can I effectively install a vapor barrier over where the rim board and the floor joists are. None of that foam has been trimmed, yet. Ideally, this would've been done with CCSF and voila! but wondering what solutions I have now that this is screwed up. Thanks.
Can you post a picture.
__________________
Do not use flat bottom gables with scissor trusses.
Nealtw is online now   Reply With Quote
Sponsored Links
Advertisement
 
Old 02-27-2019, 12:55 PM   #3
Property Mgt/Maint
 
Join Date: Mar 2015
Location: Upstate NY
Posts: 5,819
Rewards Points: 6,884
Default

Re: Vapor Barrier over Open Cell Rim board/Floor joist


Quote:
Originally Posted by Ajk2004 View Post
Hey Guys,
Long story short. My insulation contractor sprayed the wrong foam (open cell) in my house..



Wow! Huge issue. It's like asking for a Cadillac and the dealer delivering a Buick. The R value in every wall or ceiling sprayed with open vs closed cell has been cut in half from what was planned. It has implications regarding HVAC design, overall efficiency, the cost of your utilities, vapor transmission and air sealing. Not to mention the cost is half of closed cell.


Regarding the specific rim joist. It could be a issue. Ideally the air sealing should occur at the joist surface. Putting the air seal at the inside can trap moisture against the rim joist. JMHO, I would want it removed and corrected. It is a big deal with the potential for costly ramifications.
__________________
[political signature removed]
Yodaman is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 02-27-2019, 03:10 PM   #4
Newbie
 
Join Date: Sep 2018
Posts: 17
Rewards Points: 8
Default

Re: Vapor Barrier over Open Cell Rim board/Floor joist


Definitely a bummer. I had my wife write him a check that day and when I got home.... Communication ceased, go figure after that. I got scared and cancelled the check. He offered to trim the foam and I obliged and he never showed, and never showed so I told him to forget it and I would handle it. I'm hopeful it goes to court. I offered him $1000 for the job and wrote a check and sent it to him but haven't heard from him in over a month so I'm waiting for something to happen.
Back to the floor joists. I've been told I could spray a liquid vapor barrier. I've looked up some products and from what I've found, they are meant for the exterior of a building but the salesman said they can be applied indoors as well. I think it is called AirShield. WM meadows is the mfr. I have housewrap on the outside of the home. I have had to hang vapor barrier on all of the walls, which I hadn't planned on doing and everything is ready to go but this issue has me stumped. I really don't want to rip it out. I don't know if I can handle that workload. I'm pretty depressed about the whole thing and can't fathom ripping out what is there and doing something different. I'll be damned if I can find anything online on the matter. I'm sure I'm not the only person this has happened to.
Ajk2004 is offline   Reply With Quote
Old 02-27-2019, 04:49 PM   #5
Property Mgt/Maint
 
Join Date: Mar 2015
Location: Upstate NY
Posts: 5,819
Rewards Points: 6,884
Default

Re: Vapor Barrier over Open Cell Rim board/Floor joist


If you insist on not taking it out, it may be best left with out a vapor barrier. And only use a vapor retarder, this will allow some drying to the inside. Bud is one of the resident insulation experts on here and will likely chime in at some point. Keep bumping your thread as needed to stay on the front page.
__________________
[political signature removed]

Last edited by Yodaman; 02-27-2019 at 04:59 PM.
Yodaman is offline   Reply With Quote
Old 02-27-2019, 05:42 PM   #6
Newbie
 
Join Date: Sep 2018
Posts: 17
Rewards Points: 8
Default

Re: Vapor Barrier over Open Cell Rim board/Floor joist


Yodaman,
Thank you for your advice. I COULD rip it out but I'm so sour at all of the work I had to pour into a job that I hired out. He was to spray CCSF and the deal was that I would trim off/clean up after him. OC and CC are different animals. I was expecting to trim any overspray off of the studs, not trimming every. single. stud bay. He acknowledged that he thought I wanted open cell and that he would come and trim everything off. And never came. I couldn't wait longer as I needed to get drywall going.

I'm anxious to hear from Bud. Like I said above, I could rip it out, I just can't find the gumption to do so right now. If Bud thinks I could get by without it, that would be awesome. I thought about putting vapor barrier in each little bay, but I don't know how effective I would be at truly sealing everything up. The foam is of varying thicknesses so I would have to trim everything a little if I wanted to put pink foam in and seal around that. I am willing to do all of it, just tired at this point. I should add that this is a second story addition. It has been no easy project, doubling the size of your house. Some days I'm not sure it has been worth it, but each day is a small victory and keeps me pushing on. I have done 80% of the work myself, with the remaining coming from friends and family. Thanks for the help guys. I look forward to moving on with this debacle!
Ajk2004 is offline   Reply With Quote
Old 02-27-2019, 06:58 PM   #7
retired framer
 
Join Date: Jun 2017
Location: Fraser Valley BC Canada
Posts: 28,165
Rewards Points: 24,220
Default

Re: Vapor Barrier over Open Cell Rim board/Floor joist


Fit a piece of drywall behind it and caulk around the edges.
__________________
Do not use flat bottom gables with scissor trusses.
Nealtw is online now   Reply With Quote
Old 02-27-2019, 07:07 PM   #8
Property Mgt/Maint
 
Join Date: Mar 2015
Location: Upstate NY
Posts: 5,819
Rewards Points: 6,884
Default

Re: Vapor Barrier over Open Cell Rim board/Floor joist


I did think we were dealing with the rim joist on first floor above a masonry wall. One accepted method is to cut foam board to fit each cavity. Loose fit, and spray foam around the pc.
What is the make up of the entire wall? There really are a lot of details needed to avoid condensation. Including climate zone.
__________________
[political signature removed]
Yodaman is offline   Reply With Quote
Old 02-27-2019, 07:58 PM   #9
Member
 
Join Date: Nov 2015
Location: Maine
Posts: 8,316
Rewards Points: 6,752
Default

Re: Vapor Barrier over Open Cell Rim board/Floor joist


Hi Ajk, been dealing with doctors. Clarify where this rim is located, between first and second floor or around the top of the foundation?

Neal and yoda are doing just fine and as for open cell foam I have zero experience. OC would air seal better than fiberglass but is very moisture permeable and otherwise should be treated just like fg. As for vapor barriers your climate region should not require ANY, unless your local codes are behind the times. This link may help explain and I have others.
https://www.energyvanguard.com/blog/...rrier-Probably

The concept of using plastic vapor barriers got started with wrong assumptions but ended up getting adopted everywhere. Time is the test for many things and time has shown that allowing an assembly to dry is far more important than trying to keep some of the moisture out. Consider, when you turn on your air conditioning a vapor barrier on the inside is on the wrong side.

Bud
__________________
I volunteer my help and opinions, but you are responsible for what YOU choose to do with that information.
Bud9051 is offline   Reply With Quote
Old 02-28-2019, 11:36 AM   #10
Newbie
 
Join Date: Sep 2018
Posts: 17
Rewards Points: 8
Default

Re: Vapor Barrier over Open Cell Rim board/Floor joist


Bud, the area I am questioning is between the first and second floor. I plan on doing the basement rim/floor joists this summer as there is currently nothing on them. I don't know if I mentioned but I am in Iowa. I feel like it is air sealed pretty well. I have a good quality housewrap and all of the seams are taped. The article is pretty interesting. So, you think I should be okay if I don't put anything on the rim? The article seems to state as much, just looking for someones opinion who knows what they're talking about, and you certainly seem to. Thanks to everyone!
Ajk2004 is offline   Reply With Quote
Old 02-28-2019, 12:10 PM   #11
Member
 
Join Date: Nov 2015
Location: Maine
Posts: 8,316
Rewards Points: 6,752
Default

Re: Vapor Barrier over Open Cell Rim board/Floor joist


I'm far from a pro on foam products but with the open cell located between floors i suspect it will perform no differently than fiberglass which is often used in that area.

As a note (probably too late) but good air sealing is done with the help of a blower door and infrared camera, especially during cold weather. Depressurize the house with a blower door (or big window fan) and inspect with an IR camera to see where cold air is leaking in to replace what is going out. Air sealing without this approach is like doing so with your eyes closed. Using the above will certainly open those eyes.

Having someone actually use a blower door will also quantify the leakage so you will know if you need added mechanical ventilation like a HRV (heat recovery ventilator).

Bud
__________________
I volunteer my help and opinions, but you are responsible for what YOU choose to do with that information.
Bud9051 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply


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
one piece garage door should stay open at any angle? pman6 Windows and Doors 2 06-12-2013 01:21 PM
Fiberglass vs open cell foam in attic under roof Nhfixit Insulation 6 05-21-2013 11:11 AM
open cell or closed cell in attic?? JulesB Building & Construction 4 02-13-2011 10:09 AM
garage door open light deck hand Electrical 3 01-22-2008 09:29 AM
New ball valve leaking half open? sz8 Plumbing 5 01-05-2007 11:46 PM




Top of Page | View New Posts