+ Reply to Thread
Page 1 of 2 12 LastLast
Results 1 to 10 of 11

Thread: vapor barrier

  1. #1
    Join Date
    Dec 2008
    Location
    ontario
    Posts
    17

    Default vapor barrier

    i want to insulate interior basement walls, they poured wall, house is about 60 years old. walls are dry no dampness, just dam cold. there seems to be some indifference as to vapor barrier. some say against wall, others over rigid board. all this due to not allowing mold or milldew. then i saw something about if you paint your walls with a waterproof paint or a latex vapor barrier sealer. you dont need another.
    so correct me if i'm wrong. but if i was to strap the walls 2x3 or 2x4 to the wall after using on of the above. then use 2" rigid board insulation between studs filling any gap with expand foam. and just drywall over the rigid board. would this not be good enough. even if i painted the studs before attaching to walls for extra protection.
    confused by all that i have read about using 6 mil plastic covering and having to tape all the seams and everything.
    anyway open to corrections thanks

  2. #2
    Join Date
    Aug 2007
    Location
    The Great White North
    Posts
    4,045

    Default Re: vapor barrier

    Condensation will occur when warm moist air contacts a cold surface.
    So ... regardless if you were to paint the concrete walls with whatever type of paint or apply 6 mil plastic directly to the walls you would still have condensation.

    In other words .... the vapor barrier is preventing the vapor from the inside space contacting the cold wall surface ...... not from the outside in.

    The idea of the insulation is to raise the temperature of the wall surface preventing the warm moist inside air from reaching it's dew point and condensing.
    There shouldn't be an issue with condensation if the basement wall is isolated from the warm air within the room.

    You might consider attaching rigid foam insulation to the foundation walls first completetly covering the walls..... if you use 2 inch you are getting approx. R9.


    When gluing the foam in place use a continuous bead along the 4 perimeter edges ........ use a construction adhesive that's compatible with foam ....... otherwise with the wrong type you may end up with a undesirable chemical reaction that will melt the foam.

    In the corners you can use spray foam in a can to seal ... all butt seams use a house wrap tape to seal those joints to ensure the insulation is properly installed and well sealed to prevent warm moist air getting in behind the insulation.


    Another area that is important to insulate will be the rim perimeter joist.


    The closed cell rigid foam insulation has a low air and miosture perm. value which means it doesn't pass air and miosture very easily and is an acceptable vapor barrier.

    There is no need to apply any additional vapor barrier with this method.


    Then put up the wall framing in front of the foam and apply your drywall finish to the studs.
    What you end up with is a continious thermo break behind the wall framing which is far superior to the interupted method of insulating each stud cavity.

    Just a thought.
    "" an ounce of perception -- a pound of obscure "
    - Rush

  3. #3
    Join Date
    Dec 2008
    Location
    ontario
    Posts
    17

    Thumbs up Re: vapor barrier

    thank you canuk for your information, when you mentioned about insulate rim perimeter. since the floor joists sit about 2" above top of wall on sill plate and is about the same 2" recessed in from edge. i'm going to have to run 2x2 across the top to bring it flush to top of wall. to fasten top stud to. fill any uneven gap with foam spray insulation between. there is original insulation between floor joists and top sill plate and floor. that i'm replacing with newer roxul R-14 batts. since i'm going to use 2x3 with the widest against the wall and fasten to wall using tapcon screws thru rigid board into concrete wall. to support drywall and any shelving or hanging of anything afterwards. do i need to fill the gap between drywall and stud 1 1/2" with 1 1/2 rigid board or batt insulation just to make drywall ;ess receptable to dents or punttures.
    i put a couple of pic's so you can see what i mean about top sill plate not flush with wall around perimeter. hopefully what i want to do i can finally get started and get some comfort downstairs.
    thank you again for your valuable information.
    have yourself a Merry Christmas
    p/s hide your beer Santa drank all mine last year
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	2008_1218baement0005.jpg 
Views:	93 
Size:	15.7 KB 
ID:	1928  

  4. #4
    Join Date
    Jan 2008
    Posts
    731

    Default Re: vapor barrier

    buildingscience.com website has some very good information that addresses your questions including specific recommendations your region (geographic, climatic).

    you didn't say if your intent was to convert this space to conditioned space (not just heat it in winter but control humidity and temperature in the summer), habital space, or keep it as general storage space or unconditioned space and just reduce the cold penetration, that would also effect your "best" recommendations.

    you might keep in mind isolating whatever you strap to the wall from the wall and wall finish you create, for both temperature and moisture migration.

    good luck with your project planning.

  5. #5
    Join Date
    Dec 2008
    Location
    ontario
    Posts
    17

    Default Re: vapor barrier

    thank you blue ridge i'll check out your link. sorry about that but the most part of the basement to use for rec room as tv and computers are down here. we dont use the living room and want to make it more comfortable all year round in the basement.
    Last edited by don_1949; 12-24-2008 at 07:37 PM.

  6. #6
    Join Date
    Jun 2007
    Location
    near St. Paul, MN
    Posts
    166

    Default Re: vapor barrier

    One more thing….

    If you haven’t already done so it would be advisable to have your basement tested for radon. It is always a good idea to do this but since you are going to be spending more time down there it once it is finished it is even more of a priority. If you need to put in a radon mitigation system it would be best to do that before you start the finishing work.

    Good luck.

  7. #7
    Join Date
    Dec 2008
    Location
    ontario
    Posts
    17

    Default Re: vapor barrier

    thanks sherry but now another problem has come to surface. before i even think about insulating. we've only been in this house about 4 months. we are in cambridge ontario and over the last 2 days lots of snow and rain. last night i noticed part of basement wall water was seeping thru. on the outside where the driveway meets the foundation there is about 1/2 gap between the two. after doing a search for cures for interior wall i came acroos a product not sure if it's available or can be ordered here is. RADON-SEAL DEEP PENETRATING CONCRETE SEALER has anybody used it or heard of it, and if it will cure the problem from using inside on walls. i was going to fill the gap outside with a tar substance, but would probably have to wait now for warmer weather to use it so it just wouldn't instant freeze. the pic's show inside of the wall and outside where it's coming from ?????.
    any help on this one p/s thats not panelling on wall just wallpaper to look like it, oh ya where its seeping thru the wall looks like it already had a repair before
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	2008_1226baement0001.jpg 
Views:	65 
Size:	13.1 KB 
ID:	1929   Click image for larger version. 

Name:	2008_1226baement0002.jpg 
Views:	65 
Size:	16.8 KB 
ID:	1930   Click image for larger version. 

Name:	2008_1226baement0003.jpg 
Views:	72 
Size:	13.6 KB 
ID:	1931   Click image for larger version. 

Name:	2008_1225baement0005.jpg 
Views:	83 
Size:	19.0 KB 
ID:	1932   Click image for larger version. 

Name:	2008_1225baement0011.jpg 
Views:	74 
Size:	17.6 KB 
ID:	1933  


  8. #8
    Join Date
    Aug 2007
    Location
    The Great White North
    Posts
    4,045

    Default Re: vapor barrier

    You call that lots of snow ?


    In light of this I would recommend you hold off building out your basement until after the spring thaw .... this will give you an opportunity to see if any other leaks are present.
    You need to address these issues before thinking about closing in the walls otherwise you are in for a lot of problems with chances of mold and ruining the materials being put in .... wasting money and causing health issues.

    As for what the cause for the leak .... it could be a couple of things.
    There could be a crack in the concrete or the form ties used have rusted away leaving a hole.

    Repairing the issue should be considered properly doing this from the outside. Rarely does repairing these types of issues from the inside resolve the problem of water penetration ..... as you indicated it appears this was attempted already .... a band-aid.

    Many times a crack or hole is patched with hydraulic cement from the inside. While the cement is effective it won't help if a crack grows in size.

    Unfortunately doing this from the outside is disruptive especially since your driveway is right up against the foundation.
    However ..... excavating down to the footing will allow you to repair the source of the leak .... patch the hole or crack .... apply an elastomeric waterproofing material along with an isolation membrane or a sheet of extruded foam insulation would be a more effective permanent solution.

    Also, look along the walls close to where it meets the floor for signs of a white powdery substance ( efflorecense ) which would indicate the exterior drains ( weepers ) may not be functioning properly. If they aren't working properly or plugged .... this won't allow the water in the soil surrounding the foundation to properly drain ..... allowing this water to build up in the soil and with the pressure exerted by the soil will be forced through the foundation walls wherever there is a path ( crack or hole ).

    The paint on products are not the remedy for stopping water infiltration in your case and would be a waste of money ..... in my opinion. You won't find any respectable foundation contractor using or warrant this type of product.

    Just a thought.
    "" an ounce of perception -- a pound of obscure "
    - Rush

  9. #9
    Join Date
    Jun 2007
    Location
    near St. Paul, MN
    Posts
    166

    Default Re: vapor barrier

    I agree with Canuk on solving the water problem first. It is a big job to dig down to your footing and probably beyond a DIY project. But if you do try to tackle this yourself make sure you properly stabilize the soil next to the excavated area so that it does not collapse while you are in the trench. This could kill you.

    I wouldn’t rely on a crack filler to keep radon gasses out. Even if it worked (and that is highly doubtful) that doesn’t prevent more cracks from forming. The St. Paul health department gave a presentation where I work on radon and they specified that a proper remedy for radon was an underslab radon mitigation system. They also showed this method on an “Ask This Old House” episode a couple years ago.

  10. #10
    Join Date
    Aug 2007
    Posts
    1,131

    Default Re: vapor barrier

    don,

    Where does that downspout we see in the one pic dump its load?

    I'm sure you catch my drift.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •