Reuben's Home Inspection Blog

This year, I’m thankful for closed-cell foam insulation. Yeah, that’s right.

November 22nd, 2011 | 45 comments

Yes, you read that right.  I’m thankful for closed cell foam insulation.  Of course, I’m thankful for my family, health, and all that other jazz, but this is a blog about home inspections and home related topics, so I’m going to stay focused on that.  To fully explain why I’m so thankful for closed cell foam insulation, I first need to complain about my house a little bit.

My thirteen-year-old Maple Grove house has an unfinished basement with a walkout; this means about half of the basement walls have a poured concrete foundation, and the other half, the part that’s above grade, has conventional 2×6 wood framing.  The foundation walls are insulated at the exterior with rigid foam; this is a great way to insulate a foundation, because it means that the concrete walls will be relatively warm, and the potential for condensation problems will be minimized.  If you want to read more about foundation insulation methods, click this link – foundation insulation.

Fiberglass insulationThe stud walls, on the other hand, were insulated the same way as 99.9% of the houses in Minnesota – with fiberglass batts.  Yuck.  While this is the standard way to insulate a wall, it’s also probably the worst acceptable way to insulate a wall.  The photo at right gives a great example of how fiberglass batts are installed incorrectly all the time; just look at those gaps around the junction box.  I’ve already dedicated a blog to complaining about fiberglass batts, so enough on that topic.

In addition to having fiberglass batts for insulation, the vapor barrier in my basement was basically useless.  Here’s how a vapor barrier is supposed to work: to prevent air from passing through the fiberglass insulation and creating moisture problems in the wall, a vapor barrier gets installed.  This consists of 6 mil polyethylene sheeting (aka ‘poly’, aka ‘Visqueen’) that has been made airtight; that means caulked, overlapped, sealed, taped, etc.  On a home built today, this will be done quite well.  On a house that’s thirteen years old… no way.  The vapor barrier will probably be just about useless.

Unsealed vapor barriers create heat loss.  Just thirteen years ago, vapor barrier were never sealed. It was standard practice to just use a stapler to throw the poly on the walls and leave everything completely unsealed.  This practice allows for air to constantly circulate within the fiberglass insulation, creating a convective loop, which means a lot of heat gets lost through the walls.

I have my ‘office’ set up in my unfinished basement, so I spend a lot of time in the basement.  During the winter it gets very cold in my basement, despite the fact that I have 2×6 walls filled with fiberglass insulation.  Last winter I kept an electric space heater under my desk to keep my toes from turning in to icicles.

rim joist insulationFiberglass should never be used at rim spaces.  The rim space is the area between the floors of a house; this is an area where it’s nearly impossible to install a proper vapor barrier.  Without a vapor barrier, condensation can occur at the rim space, creating mold growth or eventually rotting out the rim space.  This is why fiberglass insulation should never be used here.  On new homes, it never is.  The only type of insulation that gets used on new construction homes in Minnesota is closed cell spray foam insulation; we’ll come back to that in a minute.

Unsealed vapor barriers can lead to mold growth.  When a vapor barrier isn’t sealed and air is allowed to freely pass through the wall, what happens when warm, moist air hits a cold surface?  It condenses.  My basement stays relatively cool and dry throughout the year, so the vapor drive is really happening from the exterior during the summer.  The walkout part of my basement faces south, so this part of the house is where I have the greatest temperature differential between the exterior and interior of the walls.

During the summer, as humid outdoor air passes through my walls and hits the relatively cool vapor barrier, the moisture condenses.  This summer there was never enough moisture to actually drip down to the floor, but it was enough to leave drip marks in the insulation and allow mold to start growing between the insulation and the vapor barrier.  This wasn’t major and I don’t have mold allergies, so I wasn’t too whipped up about this… but I couldn’t allow this to continue.

Mold in fiberglass batts Mold in fiberglass batts 2

Enter closed-cell spray foam insulation.  To address all of the insulation, mold, and vapor barrier issues at the same time, I had the wood framed walls in my basement completely re-insulated about three weeks ago.  I had the vapor barriers removed, all of the fiberglass insulation removed, and closed cell foam sprayed in to the walls and rim spaces.

Foamed walls

I love it.  Closed cell foam acts as a perfect vapor barrier after 2″, it doesn’t allow for convection, and it has a much higher insulating value than fiberglass.  Now when I walk down to my basement, I don’t feel a drastic change in temperature; my basement is only about two degrees cooler than the rest of my house.  I can sit here at the computer without a space heater, and I no longer freeze my toes off.  Life is good.

Having foam insulation sprayed in to the walls was expensive, but it was worth every penny.  Will I ever get a payback in energy savings?  I’m not sure.  I didn’t even bother to check the numbers, because my main motivation for this project was comfort.  Saving energy and not having mold growing inside the wall cavities is just a bonus.

Happy Thanksgiving.

Reuben Saltzman, Structure Tech Home Inspections – EmailMaple Grove Home Inspector

        

45 responses to “This year, I’m thankful for closed-cell foam insulation. Yeah, that’s right.”

  1. Reuben
    November 22, 2011, 10:50 am

    I see the roll of duct tape on your desk. You must have been doing some plumbing work too, right?

  2. Reuben Saltzman
    November 22, 2011, 11:07 am

    Good eye! Yes, I was using the duct tape to patch a leaking water heater. Duct tape is good for more than just leaking water pipes ;-)

  3. Stacy
    December 12, 2011, 6:29 pm

    Question: We recently found out we had a major mold problem in our finished basement apartment – where my husband and I sleep. We had a waterproofing/remediation company demolish everything down to the studs, remediate, and put in a waterproofing perimeter system on the inside (exterior) walls. They have now put a vapor barrier from the ceiling down to the floor into the perimeter system (which is now cemented). My question: Is it ok to put closed cell foam over the polyeurethene vapor barrier??

  4. Insulating A Rim Space | Structure Tech Home Inspections
    December 13, 2011, 4:58 am

    [...] at is the rim space.  I mentioned this a couple weeks ago when I wrote my post about how I had my entire basement re-insulated, but today I’m going to focus on the rim space alone and discuss the different options for [...]

  5. Reuben Saltzman
    December 13, 2011, 5:18 am

    Stacy – I can’t think of any reason why not.

  6. Tim Smalley
    December 13, 2011, 10:21 am

    Back in the late 1970s, I went to a basement remodling seminar at Knox Lumber (remember them?) in Duluth. The guy – who also moonlighted as a city building inspector – said insulation on basement walls should only go down a foot or so below grade to allow for heat to escape through the block. This was to keep a thawed slurry of dirt against the block to prevent frost from pushing in the basement walls. Was this EVER true???

  7. Reuben Saltzman
    December 13, 2011, 3:32 pm

    Tim – I honestly don’t know. It’s funny, I just got off the phone with a home inspector in Seattle who was asking about the same thing. It makes sense… but I think that if water management is proper, the frost issue shouldn’t be a concern.

  8. Charles
    December 13, 2011, 3:50 pm

    Hi Reuben, being that other inspector in Seattle, I would like to reiterate that it always comes back to proper water management—for so many things related to our homes:) The forces of frozen earth against a foundation can be extreme—it simply cannot be allowed to happen and if that means loosing heat from the basement to prevent it, I guess that is what has to happen. I would hope that this would NEVER be a consideration in new construction and that proper drainage and fill materials would be a given.

  9. Insulating your basement? Start with the rim joist. « About Fiberglass Construction
    December 14, 2011, 7:34 pm

    [...] at is the rim space.  I mentioned this a couple weeks ago when I wrote my post about how I had my entire basement re-insulated, but today I’m going to focus on the rim space alone and discuss the different options for [...]

  10. Dustin
    December 22, 2011, 7:55 pm

    From my understanding- with the exception of the rim joist, it is not permissible to have exposed spray foam insulation as you have pictured in your unfinished basement due to flammability. Is this correct?

  11. Reuben Saltzman
    December 26, 2011, 4:40 am

    Dustin – correct. The spray foam will all need to be covered over.

  12. TE
    April 1, 2012, 2:31 pm

    Mold detected behind my vapor barrier in basement after removing sheetrock. Also existing poly -non sheetrocked previously has same small dots of mold all over the insulation and discolored marks (mold about to happen). .
    Is this also going to be present in the upstairs?
    (which is entirely finished)

    Basement has no cold air returns and walls leak air really bad. How to remedy ?
    Plan – Installing gutters, removing insulation, sealing wall with something?
    framing walls, installing cold air returns along center of basement length.
    pulling all windows, re-wrapping and installing with new J channel and actual flashing this time.

    I just want to do it right. Should i be investing in closed cell for block knee wall and open-cell for upper wall? Should i vaporlock the buildrite 100percent and seal the block with cement water stopper stuff ? :)
    Please and thank you !
    Sincerely, Terry.E

  13. Reuben Saltzman
    April 3, 2012, 7:09 pm

    Hi Terry,

    I’d love to just throw out some answers, but the correct answer needs to be a holistic one that takes everything in to account. You would do well to hire someone to inspect your house to figure out what caused the issues and what the best repair would be. All I would really be doing is guessing. Sorry I can’t be of more help.

    – Reuben

  14. Earl
    April 15, 2012, 11:42 pm

    We have a small rental house with a mold problem. The lower area (3′)of the exterior walls are cement block. The inside has sheetrock directly over the cement block. We have condensation and mold on the lower part of the walls. We want to correct the problem. Our plan is to remove the moldy sheetrock, cover the cement with 2″ closed cell rigid insulation and new sheetrock. Is this a good plan to eliminate the problem? The house is in Lewiston, Idaho. Would appreciate good advise.. Earl

  15. Reuben Saltzman
    April 16, 2012, 4:10 am

    Hi Earl,

    I don’t much about how houses work in Idaho, but if you’re getting mold on the walls as a result of condensation, your plan might work.

  16. TE
    April 23, 2012, 12:06 pm

    Now my knee wall is just block and 6ml Poly, studs, batting and sheetrock.
    Before it was poly on the block and sheetrock side of the stud knee wall.
    No moisture or mold grew in between this vapor-locked section.
    The mold spots were showing up 1 to 3 feet below the rim underneath the sealed poly.

  17. TE
    June 4, 2012, 10:30 am

    Now we discovered the exterior has no block seal or housewrap. This is the cause of the house breathing too much and too fast. Also the furnace overworks itself in the winter constantly on.
    selling> 1 House.
    Always do a pre-inspection when purchasing your home. We didn’t.

  18. Tim Fox
    October 15, 2012, 10:46 am

    Reuben,

    I am finishing a section of my basement in SW Minneapolis (house built in 1946 – no moisture problems ever in the basement). I keep hearing all sides of the moisture/barrier issue here. I have heard from many that in Minnesota, having two barriers traps moisture in the fiberglass and people are having mold problems. I don’t know if I can afford this closed-cell foam (although it sounds great).

    For our area, the consensus seems to be: concrete block/ 6 mil moisture barrier/ kraft-faced insulation/ sheetrock. With a dehumidifier, this allows any moisture in the wall to dry to the inside of the basement.

    Is this a good idea or a bad idea?

  19. Reuben Saltzman
    October 15, 2012, 3:22 pm

    Hi Tim,

    A much better plan would be to use rigid foam boards, not fiberglass. Check out this document for a great discussion of different basement insulation methods. http://www.structuretech1.com/wp-content/uploads/2012/10/BasementInsulation.pdf

  20. Tom
    November 5, 2012, 10:11 pm

    Hi Reuben,

    I’m facing the same situation as Tim (Oct 15th). I have a So Mpls home built in 1931. I want to insulate the basement which has cement blocks. I had previously read the study you suggested, and based on it planned to glue 1″ XPS against the interior wall, leave a 3/4″ gap, and then frame 2×4 and put unfaced batt insulation in the framing.

    I now have a couple of guys trying to get me to consider framing and then having closed cell foam against the wall.

    I’d really appreciate your thoughts.

    Thanks!
    Tom

  21. Reuben Saltzman
    November 6, 2012, 4:38 am

    Hi Tom,

    When it’s an unfinished basement with flat foundation walls, I don’t understand what the big benefit in using spray foam is. This coming Saturday I’ll be attending an all-day seminar taught by the author of that document, Dr. Lstiburek. I’ll try to get his two cents on this topic.

  22. Tom
    November 7, 2012, 11:57 am

    Hi Reuben,

    Thanks for your input! I’m not going to get to the walls for a few weeks, so I’ll check back next week to see if you got any new info from the seminar. I don’t like some of the things I’m reading about spray foam out-gassing.

    Tom
    PS – Is there a better way than another when blocking up the rim joists with xps?

  23. Reuben Saltzman
    November 7, 2012, 1:15 pm

    I wouldn’t even bother trying to use xps at the rim space; hire someone to spray foam it. http://www.structuretech1.com/category/rim-joist-insulation/

  24. Reuben Saltzman
    November 12, 2012, 5:07 am

    According to Dr. Lstiburek, out-gassing from spray foam insulation is only a concern while it’s being applied.

    As I mentioned about insulating the rim space, using spray foam is definitely the way to go, but you’re just as well off using xps on the foundation walls. One tip that I picked up was to use the foil-faced stuff whether it’s going to remain exposed or not; apparently it’s nearly impossible to get tape to stick to the stuff without the foil facing.

  25. Dale
    November 16, 2012, 7:44 pm

    Hi Reuben.
    I couldn’t agree more about the shortcomings with fiberglass batt insulation. Your choice of using the spray foam is wise move — expensive – yes – but well worth it.

    As far as offgasing , that will depend on the type and brand of the foam used. In some cases , as with Icynene brand of products , which are water blown and HFC , PBDE free ; the main gassing would mainly be steam in this case and as you said earlier any other gasses would be gone 24 hours after application.

  26. Dale
    November 16, 2012, 7:54 pm

    Regarding the question from Tim Smalley — the following information may help explain things.
    Up here in Canada there has been lots of research ( and continues ) of various techniques , materials , areas of insualting buildings.

    There are two basic mechanisms which can cause a basement to move because of freezing temperatures — ice-block formation and ad-freezing.

    Frost heaving: a form of ice-block formation occurs when moist soil lies under the foundation footings and the frost line or freezing-point penetration reaches deep enough into the earth to form expansive ice directly under the footings. This lifts part of the foundation up cracking the wall. In warmer weather the foundation usually settles back down. This mechanism explains why when building, we always install footings below the normal frost line. This also explains why the front porch on the old farmhouse moves up and down every year: the posts that support it do not usually go deep enough and are too far from the basement to be protected by any heat loss. Walk in basement stair wells often have frost several feet below the bottom of the stairwell, well below the footings of the basement. They should be insulated under the slab to prevent the cold from reaching down so low.

    Ice-block formation can also cave in a foundation when water saturated soil surrounds the house. As long as the basement is heated, even a little heat loss will tend to keep this ice mass from pushing inward toward the basement, but rather it will tend to push upward. If the basement of a closed cottage is allowed to reach winter outdoor temperatures, then the ice will push both up and inward, giving us the forced inward foundations we often find in the cottage in the spring. Good landscaping can prevent the saturated soil conditions that are necessary for this to happen so that even if things do freeze, there is not enough water to create an ice block, or use a well draining soil that will not hold water.

    Ad-freezing is the most bothersome form of freezing. Heat is dissipated upwards into the atmosphere causing the soil to cool. When the top layer of soil reaches freezing temperatures it forms a horizontal layer of ice. If the soil is a clay type of soil, the bottom of this layer of ice sucks water from below, thus becoming thicker as the soil below becomes dryer. When the soil is too dry to allow the capillary action of water upward, the temperature then begins to penetrate lower until it reaches water and forms another layer (or lens) of ice. The end result is a series of ice layers, the total of which is larger than the original soil volume — meaning that everything has shifted upwards, or more precisely in the direction of heat loss.

    Under certain conditions, these ice layers can latch onto the surfaces of poles or foundation walls, lifting these upward with the ice field. For a basement wall, this means a horizontal crack across one or all of the walls as the house is lifted by the “upper portion” of the basement wall. Unprotected support posts or wing walls are especially vulnerable to this problem, often carrying portions of the house up with them.

    Every one of the following conditions must be present for ad-freezing to present a problem:

    — There is no heat source to break the bond between the ice lenses and the post or wall. (Heavily insulated basement walls will allow the soil to freeze right next to the wall, but still have enough heat loss to weaken the bond between the ice and the wall — hence preventing problems with the wall. Prairie research in Canada has shown that you can have full height basement insulation, inside or outside and not create frost shifting problems, as long as the basement is heated. Unheated basements have no such protection.)
    — The soil is a clay type which can conduct enough moisture upward through capillary action to furnish water for the building of ice lenses.
    — Sufficient water is present in the soil.
    — The surface of the wall is of such a nature as to allow the ice lens to grab a hold. (Cinder blocks are more vulnerable than poured concrete.)
    — Frost penetration is deep (cold winter with little or no snow cover).

    Hopefully this helps.

  27. Dale
    November 16, 2012, 8:07 pm

    Actually using house wrap tape does indeed stick well to rigid foam panels without the need of foil covering.
    This is one method we use for sealing the seams of the panels.

  28. Erica
    November 25, 2012, 9:33 am

    Hey Reuben – I am curious – we are getting closed cell foam for our attic remodel (old 1920s house with knee walls…) They are going to use closed cell foam on the roof and gable walls, but they said it’s better to leave the knee walls without insulation since we’re sealing the roof? I am not an expert obviously…. but does this make sense? I’m in MN as well.

  29. Reuben Saltzman
    November 25, 2012, 1:30 pm

    @Dale – excellent explanations and commentary. Thanks.

    @Erica – yes, what they’re telling you is correct. There would be no point in insulating the knee walls, because they would be completely inside of your thermal envelope.

  30. Tom
    December 3, 2012, 9:53 pm

    Hi Reuben,

    I posted earlier about the choice of xps against below ground cement block wall vs spray foam. Weighing the cost/benefit I decided to go with xps on the walls, 1/2″ gap and fiberglass within framing. However, maybe I read too much but…

    Is there a potential issue with cement block degradation because of the xps glued against it and nowhere for the moisture to go? I’ve seen posts from Canada which suggest using Platon (http://www.isola.com/products/basement_construction/platon_xtra_innvendig_kjellervegg) against interior basement walls to allow vapor to dissipate. Some of my walls do get moist and leak slightly from time to time.

    Have you encountered this? I’d appreciate your thoughts.

    Thanks,
    Tom

  31. Dale
    December 3, 2012, 10:33 pm

    Tom,
    Being from Canada I’ll throw in a couple of cents worth.
    Yes, the Platon or other similar air gap products are sometimes applied to the interior side of the foundation walls. But they are generally used for water control of leaky foundations. In which case this arrangement would be directing the water to a french drain system at the footer which spills to a sump and pump system to evacuate the water outside. Otherwise the water would simply run down and wet the floor.
    In this area we rarely do an interior water control system , the majority of water control ( waterproofing ) is done on the exterior unless the situation is prohibitive.
    It’s our experience that with interior moisture control, even though the water is managed ,the relative humidity ( RH ) remains higher than with exterior waterproofing.
    Bottom line is to address moisture infiltration before you even begin to insulate and finish basement walls.

    Apologies to Reuben I don’t mean to highjack your thread.

  32. Reuben Saltzman
    December 4, 2012, 4:51 am

    @Dale – Feel free. It sounds like you have experience with this, so I appreciate your input.

    I’ve seen the air gap products used only once or twice, and like you said, they were tied in to the drain tile system. Probably not needed.

  33. Tom
    December 4, 2012, 4:26 pm

    Thanks Dale! That’s what I needed to know.

  34. Brandon
    December 5, 2012, 6:33 pm

    Reuben-

    Thanks for the informative article. I recently found mold on the inside of all my basement walls in my walkout block basement built in 1993. The basement walls were framed with studs against the block, fiberglass insulation, and a vapor barrier followed with sheetrock. We had to hire a company to come and remove all the walls and clean everything back up. Now that im researching on how to put it all back together, i have a question. My plan is to build my walls 2” off the block and have 2.5” of closed cell spray foam sprayed behind with sheetrock on the outside. Im also going to install an air exchanger and cold air returns to keep the air moving. My question being if you have heard of anyone having problems with water again after spraying closed cell foam? Also, what would happen if i had a major water issue like a clogged downspout? Could a large amout of water pass through the foam, and if so how would it dry out again? I dont think i have major water issues, just condinsation that was build up behind the old walls. I just never want to have to deal with this issue ever again!!!!!!

    Thanks for your time,

    Brandon

  35. Reuben Saltzman
    December 5, 2012, 8:29 pm

    Hi Brandon, I’ve never run in to a moisture problem caused by spray foam. I’m sure they happen all the time, but I have yet to see it happen first-hand. If a lot of water leaked through the basement wall, it would probably find it’s way through the foam as well, and eventually dry out.

  36. Kara
    December 7, 2012, 11:30 am

    Hi Rueben,

    Thanks so much for this article. This summer we found the same problem in our 7 year old Albertville house. We noticed condensation and little black spots forming on the inside of the vapor barrier in our basement this summer, and within a couple of weeks there was mold throughout the basement. We pulled down all of the insulation, and replaced it, but did not put up another vapor barrier this summer for fear that the problem would start all over again. The plan was to install it in the fall when temperatures started to cool, but not so much that condensation would start forming behind the insulation. Well, child #2 was born and the best-laid plans went out the window (excuses, excuses). Now months later, we have yet to get the vapor barrier back up and here we are with wet outside walls and insulation. Now I am wondering if it is even possible to properly install a vapor barrier in a lived-in house the winter. My thought is that the outside temp would need to be the same or warmer than inside to stop the condensation so we are not sealing moisture behind the walls, but that seems almost impossible given the time of year. If only closed-cell foam was in our budget…

    By the way, your article is much appreciated as we have heard time and time again that it is unnecessary to seal the vapor barrier, and this will actually cause the problem we were having with condensation on the inside of the vapor barrier. It’s helpful to know that this is the way it was done until relatively recently (no more of the “well in MY house” argument from well-intended outsiders).

    Thanks!

    Kara

  37. Kevin
    January 22, 2013, 1:14 am

    Reuben,
    I’m about to embark on a basement remodel and
    my GC and I are looking for a reputable spray foam installer in the Seattle area. Do you have any recommendations you could share?

    Thanks,
    Kevin

  38. Reuben Saltzman
    January 22, 2013, 4:53 am

    Hi Kevin, I don’t have any recommendations, but I do know someone who probably would. Ask Charles Buell – http://buellinspections.com/ .

  39. R. Adam Darriau
    January 29, 2013, 12:30 pm

    Every situation is different, according climates and the local temperature differentials throughout the year. To avoid litigious situations down the road, if it’s a mold and moisture issue on an existing building, it’s best to have a forensic engineering firm provide a specification for thermal breaks, ventilation, etc. HVAC and radiant systems can become part of the equation. Vapor barriers can be quite harmful placed incorrectly. Often houses can be too tight, especially in freeze thaw climates that are also hot and humid in the summer. Foam should be used on the exterior of basements and framing; this way all the materials inside the foam envelope bank the interior temperature. When and if water intrusion occurs with closed cell foam, decay can go unnoticed. Spray-on closed cell foam encapsulates the wood so well, it’s slow if not impossible to dry out, and very hard to find a leak in the event of water intrusion, also it’s extremely labor intensive to repair, or make alterations. Open cell foam used under roofs is preferred for roof framing (sources say). Foam is effective sprayed on the interior, of wood framing, but time will tell how it performs with regard water intrusion. To me it’s best used as a thermal break for non-pervious materials between the external skin of a building and it’s interior structure.

  40. John
    January 30, 2013, 4:05 am

    I can not support spray foam, it is toxic. if the open cell gets wet or deteriorates it will release fumes into the house. Not only that, don’t plan on remodeling, the stuff is impossible to remove. The major reason people switched to drywall was to have easier access to the inner walls if needed for repair, termite damage, water damage, mold, electrical, gas you name it. this foam caked in your walls poses a huge problem at getting to those things for repair. I see major problems for home owners in the future who use this stuff. Probably even a few law suits. I’m staying away.

  41. Milt Rice
    January 31, 2013, 5:44 pm

    Doing a finished basement and am at the insulation stage. 6 yr old house. Reading all day and I’m totally confused what to do. No foundation leaks. I’m considering spray cc foam at ridge joists and down 2 feet below grade, then no vapor barrier fiberglass batts to the floor. NO poly cover. Joists are offset > zero to 2″ on poured concrete foundation. Good drainage outside. Low humidity inside. 35% now up to 60% in the summer. AC/heat vents and cold air intake (2) provided in project. Knowledgeable help appreciated. Central IL location, zone 5.

  42. Reuben Saltzman
    January 31, 2013, 8:23 pm

    Hi Milt – I don’t have any advice to give you on insulating your below-grade basement foundation walls. Like you, I’ve heard too many conflicting ways to do it.

  43. Keith
    February 10, 2013, 8:37 pm

    I’m with Milt on the CC 2′ down on foundation wall, plus rim joist.

    I live in zone 6 lower southeastern Wisconsin, and we built a home 10 years ago, the builder used a diaper style insulation floor to ceiling with 2×2 furring strips attached to the basement walls. We recently started our rec room as well, only to pull down the diaper insulation to find moisture/condensation on small pockets of the foundation walls, all within 2′ of the top of the wall by the rim joist. My theory to would to CC the rim joist and the first 2′ of the foundation wall. I have my studs just under 3″ off the wall as well, but am somewhat nervous of CC the entire wall for several reasons, one access to electrical, and the theory that the walls could split/crack vertically from freezing.

    I have to admit, I’ve done my fair share of research on this and I’m somewhat confused as a proper solution in these types of climates.

    I appreciate all the comments posted, certainly good to see someone always being the devils advocate to sum reasoning to some suggestions.

  44. Tom Mpls
    March 16, 2013, 7:13 pm

    Doing new room addition with full basement. Will be using a product from Hugo, MN – Insofast. Includes insulation and framing system in 2″ thick panels. Previous owners finished part of the basement in 70’s – that area done with plastic and pink foam panels. As expected it has recently shown signs of mold growth. Will be doing tear out and replace with same system as new area.

    Reports of the product’s use seem to be positive, looking for more info from others that may have used it. Work likely to start late May ’13.

  45. sue
    July 7, 2013, 2:24 pm

    I have a 3 season cottage with the basement as a kitchen living room space. The basement is block wall with one side being a walkout, therefore only the backside is covered by dirt. We need advise on whether we should insulate the walls since no heat is on during the winter. Also would we get ice buckling the walls when there is no heat on.

RSS feed for comments on this post.

Comments on posts over 90 days old are disabled, as of 1/7/14.