You require vapour barrier on the warm side (in winter) of permeable insulation such as fiberglass. Kraft paper is not a vapour barrier, and even if it was, the batts sit between the studs and therefore the barrier is broken.

What formulaross is saying is fiberglass (and the wood studs) in direct contact with the concrete wall could result in the fiberglass and wood becoming damp and even sopping with moisture and causing rotting and even mold behind the finish wall. Fiberglass is porous to air infiltration, and without the vapour barrier, the warm moist air in the room will migrate to the cold wall surface and moisture will condense.

You want to insulate, and also stop the room air from getting to the wall.

You can accomplish this two ways:

1) by installing extruded polystyrene foam insulation sheets (the blue one) against the wall before building out the stud walls, and then additionally, you could install the fiberglass batts between the studs. This way, the fiberglass and studs are isolated from direct contact with the wall, and you also have insulation. But, you will still have to provide a total vapour barrier on the warm side of this, because any thickness of the polystyrene under 1-1/2" thickness is not considered to be impermeable enough to be considered a vapour barrier. Regarding polyethylene film, if used for vapour barrier on the warm side, the film has to be totally sealed at overlappng joints and at edges of joists and floors.

2) You can install 1-1/2" polystyrene against the wall and build out as above, and if you seal the butting joints and the surrounding edges at joists and floors so you have a total impermeable barrier, ostensibly you do not require another vapour barrier on the warm side. But that may not suit an old school building inspector, if that is applicable for permit.

I believe, without referring to the building science information, this is the concept they recommend.

Ted

Thank you for the info. Unfortunately for me I think it's too late. Guess I'll just have to run the dehumidifier a lot!

"Personally, I would never pull a permit in MY city for finishing a basement. However, I'm different than a lot of folks and read as much as I can about the code and even though I don't pull a permit for basement work I still do it to code as much as possible."

Domino, this is your quote from a concurrent Permit pulling thread on this site. In reading your issue, don't you see the hypocrisy in your position on pulling permits? You feel they are a burden, yet you are constructing a finished basement that may turn into a festering mold nightmare for some future owner of your property. This type of behaviour is exactly why a permit should be pulled, and an inspection granted.

dominogold,

Are the walls finished now? If they are finished with panelling, it's not a big job to remove and replace it. I've done it several times myself. If it's drywalled, I can see your reluctance.

I definitely recommend you at least put vapour barrier over the batt insulation. That is not a major job and is not expensive, and if you do a careful job of using sealant to seal the lapping edges and at the contacts with joists and floor, you should keep the interior air from getting through to the cold wall.

Also, the area at the top should be insulated and more importantly sealed. This is the critical area, because the joist ends and rims are subject to the most air leakage and also need the insulation. You can understand why, when you see all the joist ends and rim joists sit on wood plates which sit on top of the wall at all floors. All the interfaces between the plates and the top of wall, and the joists with the plates and the subfloors are all heavy leakage areas. You may notice there are serious drafts through this area, and at the baseboard area and the whole floor (above)is cold. The cold migrates easily into the joist spaces well into the rest of the house. These areas are also difficult to seal, because of the many intersecting planes of the joist ends, plates and underside of floors. You could cut styrofoam to fit and seal it to the other surfaces. Some people try to resolve this using a simple if not as good a solution of stuffing and sealing bubble wrap into the cavity. One excellent way is to use spray foam insulation in the cavity, which will bridge all the leakage points. Once these areas are sealed you should pack insulation at least to the same extent as the rest of the wall and vapour barrier over.

Regarding installing the styrofoam against the wall to provide separation from the wood studs and fiberglass, I learned this the hard way, as I insulated, vapour barriered and panelled my basement walls at a previous house the traditional way. I did it the way they recommended back then, and thought I did a great job. To make a long story short, I ended up with sopping wet studs, fiberglass and panelling. The wood and panelling was rotting and there was a lot of mold starting to get very thick. What drew my attention that there was something amiss was hearing some grinding sounds coming from the wall. I pulled the panelling off and there were carpenter ants gnawing away on the rotting and wet wood. I found out ants and termites are attracted to and thrive in that environment.

I hope everything goes well for you.

Ted

"Domino, this is your quote from a concurrent Permit pulling thread on this site. In reading your issue, don't you see the hypocrisy in your position on pulling permits? You feel they are a burden, yet you are constructing a finished basement that may turn into a festering mold nightmare for some future owner of your property. This type of behaviour is exactly why a permit should be pulled, and an inspection granted. "

I can see your angle on this, but I don't really see the logic in this case.

First of all, plastic vapor barriers are not a code requirement in my area. Second, there is a lot of controversy on whether vapor barriers actually do more harm than good. You can google this and you find more information contradicting the use of vapor barriers as a benefit as you do positive info. Third, people have been finishing basements without a plastic vapor barrier for decades without issues from the lack of a vapor barrier.

naturelle, thanks for the info. Yes it's already all drywalled. None of my neighbors put up a vapor barrier other than the faced batts so I didn't either...plus it's not a code requirement here.

I think I will put some insulation along the top, can definitely see your point about the cold air inbetween floors causing cold floors above.

What a pain I thought I was done with the insulation hate that stuff...

Domino. I apologize for the tone of my earlier post.

Oh, not necessary really but thanks.

Look if I wasn't already paying $8000-9000 in taxes, I would would pull a permit. But there's just no way when my house was built a year ago with dozens of code violiations that "made it past their inspectors" that I'm going to pull a permit just so an incompetent inspector can give me a hard time for no reason and raise my taxes even further.

Hey Dominogold! I know this is an old thread, but what happened in the end? Did you have any difficulty with moisture/mold or did you experience a lot of heat loss? Reason I ask is my basement was partially finished before I moved in. Had to do a wall repair & discovered no vapour barrier. Just tar paper against the concrete then insulation, then drywall. Wondering if I need to rip it All down or can I just finish it off...

If your floor above is insulated (first floor/basement ceiling) you have a semi-conditioned space and you shouldn't need a vapor barrier. in this case it will trap moisture. Use only unfaced BATT.

Never insulate a basement nor install a vapor barrier- just extra costs and not necessary! First of all the earth itself is nature's insulator- average ground temperature is between 55-60F year round. In the summer the natural coolness of the ground keeps your basement "AC cool," in the winter it keeps it marginally warm and requires little energy for heating. Furthermore in the winter it is highly unlikely that the humidity will be so high or there will ever be condensation on interior walls and even if there is if you have adequate ventilation the walls will dry out naturally.

It depends on where you are located. I have always lived in Canada and the codes call for foundations and footings for buildings, decks and fence posts to be 4 feet below ground, because of frost penetration and heave. This extreme cold transmits through concrete walls. You can feel the cold on the walls and if the basement is not heated, frost will actually form on the surface. This is a fact, as I had a house with no central heat in the basement once. As well as possibly creating damaging condensation within finished walls, without insulation and vapour barrier, it can result in mold. It will also increase the cost of heating the overall house. I am a retired architect and have renovated several of my own houses which were handy men projects, so have gone through the whole gamut many times.

As pointed out years ago in this revived thread, no vapour barriers in basements and mould resistant insulation are essential in saving energy and keeping mould at bay.

It is a biological fact that heat and humidity promote mold growth - cold and dryness retard it, Concrete is a better insulator than a conductor. Also even in Canada the ground stays a balmy 55-60F even if temperatures above are sub-zero. Of course the wall feels cold- it's winter! (Will never form frost by the way unless you open the basement window) Playing devils advocate and assuming you would ever get condensation adequate ventilation in the basement would evaporate it anyway thus there should not be a mold problem.

How can the ground temp be balmy when the ground is frozen rock hard to several feet? That's why the codes require minimum depths of foundation burial. That's why you have frost heave problems. Codes (depending on where you are) require minimum levels of insulation and vapor barrier. I studied geothermal heating and cooling, because I had considered building a house incorporating the science, but you have to go down to a substantial depth to get to get to ambient temps, which are conducive to recovering the residual temperature in the ground.

Outside the "banana belt" of Ontario's Golden Horseshoe and the B.C. Lower Mainland, frost penetrates to five and six feet and more below grade. Ditto cold climates in the US.

Concrete is a better insulator than a conductor.

"The R-value of an uninsulated, 8-inch-thick basement wall built using normal-weight concrete is 1.35, based on data from the 1993 American Society of Heating, Refrigeration, and Air-Conditioning Engineers' Handbook. By doubling the thickness of the wall to 16 inches, the R-value only increases by 0.50. " *

worthy, you and I are on the same wavelength. I know people, including myself, who have found frost on the inside face of concrete basement walls, when there was no vapour barrier in those walls (I removed the cheap panelboard).

I have lived in Toronto, Montreal, Vancouver, Edmonton, Calgary, Regina, Saskatoon, and have spent a lot of time in places like Fort McMurray, Labrador City, Sudbury and points north, so I know about cold.

I am an inveterate home renovator and have studied building sciences all my life, being 76 now.

The easiest thing to do at this point is contact a local spray foam/insulation company and have the rims and walls spray foamed.

The best way to insulate a basement is from the exterior but this isn't cost effective for an existing home.