Go Back   DIY Chatroom Home Improvement Forum > DIY Repair > General DIY Discussions

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

Reply
 
Thread Tools Search this Thread Display Modes
Old 03-04-2009, 06:11 PM   #1
Member
 
Join Date: Mar 2009
Location: British Columbia Canada
Posts: 460
Share |
Default

insulating basement walls partially below grade


I need to insulate my basement walls. These walls are full height with 4 ft being below grade. I have been told that I only need to vapor barrier the top half of the walls. This does not make sense to me. The inspector (home grant inspector) stated this to me. I asked how to seal the 6 mil vapor barrier and he said just let it hang. He stated that the concrete foundation wall needs to breathe.I am shaking my head trying to figure out a way to do this right. I can't supply pics yet as I need to know how to do this right so I can create a budget for materials, so I don't end up with half a job done and no more money. Any help would be greatly appreciated.

fixrite is offline   Reply With Quote
Old 03-04-2009, 07:25 PM   #2
Remodeling Contractor
 
Join Date: Dec 2008
Location: Sandy Hook, CT
Posts: 3,590
Default

insulating basement walls partially below grade


Finally an inspector that gets it right. Yes... the below grade needs to dry to the inside. A vapor barrier like plastic will only block moist air in the insulation and collect mold. But you can glue rigid foam to the concrete, which keeps the warm inside air from condensing on the colder concrete wall. Leave a 1/2" space before your wall to allow space for the wall to dry out. Then add insulation in the studs. Kraft paper will add a vapor retarder, which the code requires, but still allow some air flow to move into the space allotted and the wall can not dry out.

Bob Mariani is offline   Reply With Quote
Old 03-04-2009, 08:00 PM   #3
Member
 
Join Date: Mar 2009
Location: British Columbia Canada
Posts: 460
Default

insulating basement walls partially below grade


ok, Normally when I have installed a vapor barrier I have used acoustic sealant on the sill plate to seal the vapor barrier. How do you use a vapor barrier for half of a wall? That is what I cannot get my head around. Would I have to install a cross brace with the insulation and vapor barrier stopping where the ground outside begins?
fixrite is offline   Reply With Quote
Old 03-04-2009, 09:14 PM   #4
Member
 
concretemasonry's Avatar
 
Join Date: Oct 2006
Location: Minneapolis/St. Paul, Minnesota - Latitude 45.057 Longitude -93.074
Posts: 3,740
Default

insulating basement walls partially below grade


Canada infamous for the insane, magic red line on the inside of a basement at the grade. Apparently, they have not discovered that building materials transfer the heat in all dimensions and NOT directly through the wall. Some day, they will take time to look at the interior surface temperatures of the wall and see they do not vary too much once you get away from the leaky (air infiltration) wood construction.

Dick

Last edited by concretemasonry; 03-05-2009 at 10:04 PM.
concretemasonry is offline   Reply With Quote
Old 03-05-2009, 05:51 AM   #5
Remodeling Contractor
 
Join Date: Dec 2008
Location: Sandy Hook, CT
Posts: 3,590
Default

insulating basement walls partially below grade


I did not notice you were in Canada. Actually it is recommended that in very cold climates the poly is used on the entire wall. As posted air moves through the concrete wall from the moist soil but also up the wall from the footer. Possibly installing a foam blocking at the area where the grade changes may help block the changing air flow. Not as cold here and I do not need to deal with this as you do. Did the inspector have a solution to this situation? Did you ask him? They are there to help and may offer the info you need.
Bob Mariani is offline   Reply With Quote
Old 03-05-2009, 09:34 PM   #6
Newbie
 
Join Date: Mar 2009
Location: Milton P.A.
Posts: 6
Default

insulating basement walls partially below grade


Quote:
Originally Posted by fixrite View Post
I need to insulate my basement walls. These walls are full height with 4 ft being below grade. I have been told that I only need to vapor barrier the top half of the walls. This does not make sense to me. The inspector (home grant inspector) stated this to me. I asked how to seal the 6 mil vapor barrier and he said just let it hang. He stated that the concrete foundation wall needs to breathe.I am shaking my head trying to figure out a way to do this right. I can't supply pics yet as I need to know how to do this right so I can create a budget for materials, so I don't end up with half a job done and no more money. Any help would be greatly appreciated.
Yes the walls do need to breath but at the same time just hanging the vapor barrier is not sufficient enough. It should be sealed properly or it will cause for moisture thus the wall would fail over time. You may also want to check with a contractor about the building codes for your area you cannot always rely on an inspector. You may want to know for yourself what is going on.
Peeps is offline   Reply With Quote
Old 03-05-2009, 10:03 PM   #7
Member
 
Join Date: May 2008
Location: Edmonton, Alberta Canada
Posts: 777
Default

insulating basement walls partially below grade


To add to your confusion, here in Alberta I've only seen insulation and then the full wall vapor barriered. No foam board on the inside of the walls. Some guys seal the sills, some guys seal every stud, others don't seal at all. The basement of our 2004 house was framed and insulated with vapor barrier but not sealed. This was acceptable to the city.

You're going to get so many varied opinions on here from everyone in different climates until your head is spinning. Take Peeps advice and ask your locality/municipality what they want.
n0c7 is offline   Reply With Quote
Old 03-06-2009, 03:15 PM   #8
Advice worth 2 cents!
 
Join Date: Mar 2008
Location: Quebec, Canada
Posts: 229
Default

insulating basement walls partially below grade


I live in the north of Québec (for what it's worth). The first and foremost way to finish those walls is with spray foam, you get great insulation and the humidity questions are solved.

The next "best way" is rigid foam sheets (pink or blue). Around here the guys hold the sheet against the wall, take a 1x2 furring strip and hold that too, then they drill a small pilot holes and nail away to the wall. The drwall goes over that and your done! (NO vapour barrier).

The "old fashion way" was to put black construction paper against the wall from top to about 3" from the bottom. Frame 2x3 verticaly and fill the voids with fiberglass batts. Finish the wall WITHOUT a vapour barrier and cut 2" x 6" horizontal holes at the bottom of the drywall to let air circulate behind the drywall.

Have fun,

_pete (an insane canadian)
__________________
---pete
HandyPete is offline   Reply With Quote
Old 03-06-2009, 07:38 PM   #9
Member
 
Join Date: May 2008
Location: Edmonton, Alberta Canada
Posts: 777
Default

insulating basement walls partially below grade


Quote:
Originally Posted by HandyPete View Post
The next "best way" is rigid foam sheets (pink or blue). Around here the guys hold the sheet against the wall, take a 1x2 furring strip and hold that too, then they drill a small pilot holes and nail away to the wall. The drwall goes over that and your done! (NO vapour barrier).
Better hope that foundation is straight.

Quote:
_pete (an insane canadian)
Like wise. Hard to type with stitches.

n0c7 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
Spray foam insulating joists in basement? peethree Building & Construction 13 11-28-2010 08:54 AM
Insulating house with stone walls mlupa Building & Construction 3 11-26-2008 09:19 PM
Drylok bubbling on basement walls. 68MHJCs Building & Construction 5 08-19-2008 07:47 AM
"floating" basement walls? greg s Carpentry 2 03-04-2005 07:56 PM
Running Conduit in new basement framed walls tben Electrical 3 12-10-2004 11:14 PM




Top of Page | View New Posts

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