Basement Insulation - Insulation - DIY Chatroom Home Improvement Forum


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 08-12-2013, 12:19 PM   #1
Member
 
Join Date: Mar 2013
Location: wright city, Missouri
Posts: 170
Rewards Points: 154
Default

Basement Insulation


Trying to figure out how much its going to cost me to redo the insulation in the basement. My question is, should I do 2in foam board or fiberglass batts? Do I need some sort of vapor barrier since its in the basement?

Also, I can't find any 2in foam board around my area. Where is a good place to buy online maybe?
Attached Thumbnails
Basement Insulation-20130419_142559.jpg  

Advertisement

word2yamutha is offline   Reply With Quote
Old 08-14-2013, 09:51 PM   #2
Exterior Construction
 
Windows on Wash's Avatar
 
Join Date: Aug 2011
Location: Washington DC Metro Area (VA, MD, DC)
Posts: 7,100
Rewards Points: 3,256
Default

Basement Insulation


Don't both with the 2".

Buy the readily available 1" and double it up. Seal the seams and seal the connections to the framing.

Seal the ribbon board prior to putting in the foam.

If you run and XPS or foil faced ISO, you don't need to worry about vapor permeance.

Cover the exposed XPS if you leave it unfaced. If you run the foil faced ISO, you shouldn't need a thermal barrier.

Code Acceptance
The International Residential Code (IRC) allows the exposed
use of spray foam at rim joists (i.e., without a 15-minute
thermal barrier such as drywall), as long as the thickness is less
than 3” (see R314.5.11). High density (closed cell, 2 PCF)
spray foams were approved in the 2003 IRC, and low density
(open cell, 0.5 PCF) foams were approved in the 2009 IRC, as
well as any intermediate densities.

Advertisement

Windows on Wash is offline   Reply With Quote
The Following User Says Thank You to Windows on Wash For This Useful Post:
word2yamutha (08-16-2013)
Old 08-15-2013, 03:14 AM   #3
Member
 
Join Date: Mar 2013
Location: wright city, Missouri
Posts: 170
Rewards Points: 154
Default

Basement Insulation


what do I cover the exposed XPS board with if it is unfaced?
word2yamutha is offline   Reply With Quote
Old 08-15-2013, 11:25 PM   #4
Registered User
 
Join Date: Mar 2009
Posts: 9,983
Rewards Points: 2,032
Default

Basement Insulation


Check locally for coverage as you have your own state code; http://www.reedconstructiondata.com/...odes/missouri/

!"XPS, foil-faced or not, will prevent condensation for your location, Warren County- Zone 4; http://energycode.pnl.gov/EnergyCode...state=Missouri

I'd add the fiberglass (1-1/2" minimum) after the f.b. for the ignition barrier, meets code and safer in fire event;http://www.buildingscience.com/docum...l_seal_rev.pdf

Gary
__________________
If any ads are present in my answer above, I do not condone/support/use the product or services listed, they are there against my permission.
Gary in WA is offline   Reply With Quote
The Following User Says Thank You to Gary in WA For This Useful Post:
word2yamutha (08-16-2013)
Old 08-16-2013, 12:13 PM   #5
Member
 
Join Date: Mar 2013
Location: wright city, Missouri
Posts: 170
Rewards Points: 154
Default

Basement Insulation


Great advice gary. So Im going to go with 2in fb and a 1in of fiberglass batts. Stupid question, but since I can only find 1in fb how should I put them together? Do I just seal them with caulk?

Also, does it matter if going above the recommended R-value? I ask this because I have blown in cellulose in the attic and was plan on adding more insulation where needed. Thanks for your time guys.

Last edited by word2yamutha; 08-16-2013 at 12:23 PM.
word2yamutha is offline   Reply With Quote
Old 08-16-2013, 09:50 PM   #6
Exterior Construction
 
Windows on Wash's Avatar
 
Join Date: Aug 2011
Location: Washington DC Metro Area (VA, MD, DC)
Posts: 7,100
Rewards Points: 3,256
Default

Basement Insulation


A foam compliant glue will work.

You need to make sure there are no volatiles in the sealant that will melt the foam. They sell it in the caulking aisles of the big box stores.

Doesn't matter about going over the code require R-Value. There is a law of diminishing returns past R-38 but be blow in R-49 as a standard. That is what Energy Star is promoting now.

I would run the insulation or drywall for my thermal barrier.
Windows on Wash is offline   Reply With Quote
Old 08-17-2013, 10:02 PM   #7
Registered User
 
Join Date: Mar 2009
Posts: 9,983
Rewards Points: 2,032
Default

Basement Insulation


Foamboard adhesive, not caulking, as said. Use a 1' grid pattern on the one against concrete wall to limit basement air/condensation; http://joneakes.com/jons-fixit-database/743

Rim joist/mud sill- use caulking on the joints; decking/rim,,,, rim/sill,,,, and sill/concrete. Add f.b. cut 1/2" shy, use canned foam in gaps, add 1-1/2" fiberglass batt.

You can add whatever you desire, lol. Air sealing the attic/basement of all wiring/plumbing holes is more important than extra insulation, past minimum code. There is a point of R-value vs. cost, at least for me; http://www.google.com/url?sa=t&rct=j...,d.cGE&cad=rja

Gary
__________________
If any ads are present in my answer above, I do not condone/support/use the product or services listed, they are there against my permission.
Gary in WA is offline   Reply With Quote
Old 08-18-2013, 09:26 AM   #8
Exterior Construction
 
Windows on Wash's Avatar
 
Join Date: Aug 2011
Location: Washington DC Metro Area (VA, MD, DC)
Posts: 7,100
Rewards Points: 3,256
Default

Basement Insulation


I agree that air sealing the attic is more important than going from 7" of insulation to 15" of insulation but I am not supremely trusting of the article on insulation depths.

If the heat flow reduction gain to go from 6" of installed to 12" installed was only 2%, I think we would see more PassivHaus homes only putting an R-20 in attics in some of their designs.

What the article does not account for is the thermal losses at the framing in the attic and the reductions in those locations and it is also assuming that there is no convective air movement.

This is much more applicable in the case of spray foam and the article was written specifically for Icynene insulation and probably for the justifications of running lesser depths in spray foams.

At the end of the day if you asked me if I would rather have 15" of cellulose over an air sealed attic floor or 6" of Icynene on the attic floor...I will happily take the 15" of cellulose.
Windows on Wash is offline   Reply With Quote
Old 08-18-2013, 09:12 PM   #9
Registered User
 
Join Date: Mar 2009
Posts: 9,983
Rewards Points: 2,032
Default

Basement Insulation


Here is my other library reference; http://www.buildings.com/article-det...g-returns.aspx

If you don't believe that one either, I'll need a link to disprove them, lol. Both links show a break point in cost/value; insulation density, attic airflow, thickness, and temperature difference to allow convective looping were not included. BTW, the low density insulation (cubed) in the '90's test (1st link) is no longer made because of a design that allowed air flow around it at low temp. differences. My point is; (still) meet minimum code required insulation (as I stated), additional above that is your choice.

Gary
__________________
If any ads are present in my answer above, I do not condone/support/use the product or services listed, they are there against my permission.
Gary in WA is offline   Reply With Quote
Old 08-19-2013, 07:11 AM   #10
Exterior Construction
 
Windows on Wash's Avatar
 
Join Date: Aug 2011
Location: Washington DC Metro Area (VA, MD, DC)
Posts: 7,100
Rewards Points: 3,256
Default

Basement Insulation


Quote:
Originally Posted by Gary in WA View Post
Here is my other library reference; http://www.buildings.com/article-det...g-returns.aspx

If you don't believe that one either, I'll need a link to disprove them, lol. Both links show a break point in cost/value; insulation density, attic airflow, thickness, and temperature difference to allow convective looping were not included. BTW, the low density insulation (cubed) in the '90's test (1st link) is no longer made because of a design that allowed air flow around it at low temp. differences. My point is; (still) meet minimum code required insulation (as I stated), additional above that is your choice.

Gary
A link to disprove a link.....

I agree.

Anytime I see a specifically named insulation mentioned about 5 times in the context of the article, I get a bit suspicious.

While I agree that the "gubberment" should not be the entity that is supposedly in charge of the scientific recommendations, I think (as you mentioned) there are other aspects of either study that may be missing and require consideration.

I don't think blowing in 18" is necessary but by the time most folks get a nominal 7" across the tallest point in the attic floor/framing, they are probably going to have about 11-12" in total depth.
Windows on Wash is offline   Reply With Quote
Old 08-23-2013, 01:13 AM   #11
Registered User
 
Join Date: Mar 2009
Posts: 9,983
Rewards Points: 2,032
Default

Basement Insulation


In the first link of SPF, the break-point was listed as R-20, second link- R-25 (heavy blue line in first graph. Table 1 shows the reduction in heat flow by adding 1" of insulation, very minimal gains after the break-point is reached. Money should be spent on other cost-saving things; than adding insulation past minimum code, IMO. If you address the "other things" before/after insulating, you would get your moneys worth without adding excessive amounts of attic insulation there.

Gary
__________________
If any ads are present in my answer above, I do not condone/support/use the product or services listed, they are there against my permission.

Last edited by Gary in WA; 08-23-2013 at 01:19 AM.
Gary in WA is offline   Reply With Quote
Old 08-23-2013, 08:24 AM   #12
Exterior Construction
 
Windows on Wash's Avatar
 
Join Date: Aug 2011
Location: Washington DC Metro Area (VA, MD, DC)
Posts: 7,100
Rewards Points: 3,256
Default

Basement Insulation


I agree.

Like I said above, I don't think going from 7"-15" is as import as air sealing.
Windows on Wash is offline   Reply With Quote
Old 08-23-2013, 09:27 AM   #13
Newbie
 
Join Date: Aug 2013
Location: Northern Wisconsin
Posts: 19
Rewards Points: 10
Default

Basement Insulation


I agree with you guyz...air sealing is most important, followed by insulation. Getting that first layer of sealing allows the fiberglass or cellulose live up to its R-value, otherwise it's just an air filter and condensation trap.
Looking at the pic, and making some guesses...after doing the foam/fiberglass on the sills...that wall section is going to be about R-25, while the poured concrete wall under it is about an R-4. That concrete is a pretty effective air barrier, but a lousy insulator...still, I'd do a home-made blower door test and find and seal all the leaks before I'd insulate that concrete.

Advertisement

Solarboy is offline   Reply With Quote
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
Basement Exterior Above Grade Insulation purpasadu Building & Construction 6 02-28-2012 05:42 PM
Insulation in basement floor joists and integrated garage speedster1 Building & Construction 3 12-07-2010 06:44 PM
Old Home - Basement addition insulation vapor barrier question 1870 Building & Construction 0 10-14-2010 08:36 AM
basement insulation advise needed bmartin5150 Building & Construction 1 04-27-2009 05:56 PM
Installing new insulation in my basement and removing the old moldy insulation. Fixitgeorge Remodeling 3 10-17-2006 09:33 PM




Top of Page | View New Posts