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

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

Reply
 
Thread Tools Search this Thread Display Modes
Old 11-21-2012, 09:48 AM   #1
Newbie
 
Join Date: Nov 2012
Location: Mid West
Posts: 7
Share |
Default

Insulating walls from exterior


We are purchasing a home that will need to have all the siding (stained wood) and sheathing removed due to insect and woodpecker damage. We live in zone 4 and the walls are 2x6 on 16" centers. All the windows are going to be replaced as well. I am torn (monetarily) on closed cell spray foam but have concerns about settling on FG or Cellulose. The plan is insulation, 1/2 ply, housewrap, 1/4" XPS (R1.6) , then foam backed vinyl siding (R1.6). My first instinct is 3" of closed cell (R18) sprayed direct to back of drywall but thats a bit $$$ so am looking for any all ideas or flaws in plan. Thanks,

cww1 is offline   Reply With Quote
Old 11-21-2012, 10:02 AM   #2
Member
 
Join Date: Nov 2011
Location: Hartfield VA
Posts: 26,246
Default

Insulating walls from exterior


I'd strongly suggest againt the insulated vinyl siding. Use a .045 high grade siding instead. The money saved could go toward having the spray foam done.

I've done a few home with the insulated siding, (customer insisted) and they all came back and report it made 0 differance in there heating and cooling cost.
There's still going to be air gaps where the seams are and around all the inside and outside corners,windows and doors like with any siding.

Sure hope your getting this house for a steal, a whole lot of work and money to do what your suggesting.

joecaption is offline   Reply With Quote
The Following User Says Thank You to joecaption For This Useful Post:
mae-ling (11-21-2012)
Old 11-21-2012, 09:48 PM   #3
Registered User
 
Join Date: Mar 2009
Posts: 9,968
Default

Insulating walls from exterior


I'd use R-5 insulating sheathing to stop thermal bridging/cavity condensation: http://publicecodes.cyberregs.com/ic...9_6_sec001.htm

Read up on it: http://www.buildingscience.com/docum...ting-sheathing

Flawed: http://www.buildingscience.com/docum...l-construction

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 11-21-2012, 11:28 PM   #4
Member
 
cocobolo's Avatar
 
Join Date: Dec 2008
Location: Gulf Islands, B.C., Canada
Posts: 6,590
Default

Insulating walls from exterior


I think you will get far more bang for the buck if you use 5 1/2" Roxul batts in the cavities. Then cover that with a 1" or 1 1/2" foam board (usually EPS) and then your 1/2" plywood. Spray foam is quite costly.

I agree with Gary concerning the thermal bridging, which is VERY important to keeping your overall wall R rating high.
__________________
Just an old guy messin' with bits of wood...
...the friendliest thread on the site! Come on by.
http://www.diychatroom.com/f49/gulf-...uilding-34958/
cocobolo is offline   Reply With Quote
Old 11-22-2012, 07:26 AM   #5
Newbie
 
Join Date: Nov 2012
Location: Mid West
Posts: 7
Default

Insulating walls from exterior


Thanks for input all and the links GBR. Should it be foam then ply or ply then foam ? Putting the ply on the outside will make it easier for siding but not sure local code will allow without additional bracing on walls, at least the corners.
cww1 is offline   Reply With Quote
Old 11-22-2012, 04:35 PM   #6
Registered User
 
Join Date: Mar 2009
Posts: 9,968
Default

Insulating walls from exterior


Where are you located?

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 11-22-2012, 08:54 PM   #7
Newbie
 
Join Date: Nov 2012
Location: Mid West
Posts: 7
Default

Insulating walls from exterior


House is in St. Louis, MO. And EPS or XPS, I think XPS has a higher r value per inch.
cww1 is offline   Reply With Quote
Old 11-24-2012, 08:33 PM   #8
Registered User
 
Join Date: Mar 2009
Posts: 9,968
Default

Insulating walls from exterior


Plywood sheathing before foamboard as per structural code. 1" of XPS (R-5) will warm your sheathing and prevent condensation there, up to 56%RH at 70* in the room. With just 1/4" (R-1.6), you are safe only to 48%RH. Local EPS may be rated at only R-3.5 per inch thickness, but I would get rid of the insects around the house first, as they love foamboard. If using ESP, install the housewrap exterior of it to control water intake/storage. If XPS, install housewrap first, tape the vertical joints in foam, and get the window/door flashing correct. http://www.buildingscience.com/docum...ting-sheathing

At annual low temp at 47*--- http://www.average-temperature.com/temps/MO/St%20Louis
your sheathing temp is at 49* with only R-1.6 f.b. or 52* with R-5.

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
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
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
Framing basement exterior walls gheffron Building & Construction 7 06-08-2012 01:00 AM
Warmth in some spots of (exterior facing) walls daluu Building & Construction 2 02-26-2012 12:00 PM
Insulate rim joist & basement walls- if exterior walls have no insulation? cbrc5eric Insulation 5 02-01-2012 07:47 AM
gain from insulating walls ratherbefishing Insulation 4 12-02-2011 09:35 PM
Framing & Insulating basment concrete walls harddy Building & Construction 8 12-02-2009 12:04 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.