My contractor built the 2×4 walls on the floor of the basement and attached the typar house wrap with the writing facing the inside before standing the walls up and securing in place. The insulation was put in and the 6mil vapour barrier was applied. This was a year and a half ago. I wanted to add a few extra plugs and cable outlets so I cut the vapour barrier and removed the insulation in order to add the boxes. To my surprise, there was some condensation on the house wrap and the back of the insulation. What is wrong? Any thoughts/suggestions would be greatly appreciated.
Thanks,
Kevin
PS: I live in Toronto, Ontario, Canada so that you know the climate that this is occuring in.
Replies
Barring the existence of a leak, I would say that you have moisture migrating from the outside and condensating against the plastic barrier.
If the wall was built in high humidity or water was introduced and subsequently trapped inside the wall (insulation got a little wet, for instance) that might be your culprit.
Every other component of your wall, except the plastic, can allow moisture to pass to some degree.
I can't say that I am completely convinced of the benefit of interior plastic barriers either.
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I'm presuming that the walls have been sided by now?
Are these are walls that are resting on the foundation, and did you cut in a few inches above the bottom plate? Probably moisture is migrating out of the foundation and into the walls. Plus there's a lot of moisture in new lumber, no matter where you look.
Unless there was enough moisture to puddle, I wouldn't worry about it. It's probably normal for a new house.
Good point about the lumber holding moisture as well. Problems like this are why I feel better about a house that breaths a little more.
I read some info about how the move for more efficient homes has been the culprit for the decrease in indoor air quality and healthiness.
When you're this good, EVERYONE wants a crack at you!
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Even back in the early 70s, before "tight" homes became common, it was normal to have winter moisture problems (condensation on the windows, etc) in new homes. It takes 2-3 years for a normal home to reach equilibrium with regard to moisture.
Half of the harm that is done in this world is due to people who want to feel important. They don't mean to do harm but the harm does not interest them. --T.S. Eliot
There is enough water that when I removed the insulation there were beads that started running down the house wrap. I don't know a lot about the house wrap but I thought maybe it was put on the wrong way? Like I said, the writing faces the inside (towards the 2x4 and insulation). When the house wrap is put on the exterior of the house the writing faces out. I assume that it repels the elements but at the same time lets the house "breath". If this is the case, than in my basement, the house wrap is letting the moisture in and then it is getting trapped between the house wrap and the 6mil vapour barrier. Does this make sense? What can I do to solve this problem? Or am I worrying about nothing. As someone noted earlier, there is always going to be some winter condensation.
Thanks,
Kevin
It doesn't make that much difference which direction the Typar goes on. The "right" way is a bit more weather-resistant until the siding is on, but once sided there's no major difference. (Even less difference with Tyvek, which I consider to be somewhat superior in most cases, but that's a different argument.)Neither product is a "one-way valve" for moisture. They both allow water vapor to pass through both ways with equal ease.I'm still having a bit of a problem understanding your precise situation. You say this is the "basement". Is there a foundation part way up, and this stud wall continues the rest of the way up from there, or something else? What's on the outside of the wall?
Half of the harm that is done in this world is due to people who want to feel important. They don't mean to do harm but the harm does not interest them. --T.S. Eliot
I have a block foundation with parging, tar, and the delta membrane (dimpled plastic) around the exterior. The grade of the house is roughly 6 ft of the basement is below grade and 2 ft is above grade (8ft ceiling in the basement). On the interior, the 2x4 walls go from the concrete floor in the basement right up to the 1st floor joists. There is R12 batt insulation from top to bottom of the 2x4 walls with the 6mil vapour barrier on the "warm" side and the typar house wrap on the "cool" side. I believe they put the house wrap on the 2x4 walls to keep the wood away from the block foundation. Hope that clarifys things. I guess the bottom line is this...Should I be worried about this moisture?
Thanks,
Kevin
Kevin,
It sounds like the moisture is coming from the foundation (either through the wall or footer, even with your waterproofing, you could get some moisture leaching through). Whether or not to worry about it depends on how much it is and what it is doing to the wall structure.
To fix this could get pretty involved....i.e. tearing the sheetrock out and insulating with blueboard or something to that effect. I'm sure there are some better ideas on how to fix it.
Bottom line, keep an eye on the wall cavity for mold and rot.
OK, so this wall is essentially below grade -- it's insulating a masonary wall. The use of a vapor barrier in this situation is controversial at best, and the housewrap really isn't appropriate either -- there are better choices to separate the framing from the masonary.
Half of the harm that is done in this world is due to people who want to feel important. They don't mean to do harm but the harm does not interest them. --T.S. Eliot
The weird thing is that the foundation wall is completely dry. I could see if the foundation was wet or you could see the moisture on the wall by the different colour. So maybe it is what someone else referred to as winter moisture. The only reason I found this was because I cut open the vapour barrier in order to put a few extra plugs and cable outlets before I put up the drywall. My concern is that after I drywall and 5/10 years down the road I end up with mold or something.
Thanks,
Kevin
Believe me, the foundation wall is NOT completely dry. It may appear dry but it is not.
Tape a few square feet of plastic over it overnight and see how wet the underside is in the morning..... you may be amazed.
In your original post, I misunderstood the situation thinking that the walls were framed in the basement and then used for the first floor walls... I know that sounds like an odd thing for someone to do but I've seen worse.
So, now I see that these walls are IN the basement. I'd have never sealed them in plastic... that is certainly asking for trouble.
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Yeah, the foundation is not dry, especially in new construction. I'll bet it still has a slight greenish tinge, in fact.I do wonder if perhaps cold air is getting in between the Typar and the foundation wall. You should check how well the sill is sealed. How much space is there between the framing and the foundation?In any event, "conventional wisdom" would suggest that it might be wise to remove or simply slit the vapor barrier on the bottom 2/3 or so of this wallBTW, where do you live, and how cold does it get in winter?
Half of the harm that is done in this world is due to people who want to feel important. They don't mean to do harm but the harm does not interest them. --T.S. Eliot
I live in Toronto, Ontario, Canada so the winters do get to -20 celcius. I thought about making slits in the house wrap every so often so that the moisture could escape. If I cut the vapour barrier than it wouldn't pass inspection for the insulation/vapour barrier phase before I can put up the drywall.
If you have to pass inspection then ask the inspectors what's appropriate. I can't believe they require a vapor barrier on the inside on basement walls.
Half of the harm that is done in this world is due to people who want to feel important. They don't mean to do harm but the harm does not interest them. --T.S. Eliot
"I do wonder if perhaps cold air is getting in between the Typar and the foundation wall. You should check how well the sill is sealed. How much space is there between the framing and the foundation?"My bet is on warm moist interior air leaking past the plastic and condensing.Could be aided by moisture coming out of the wood and concrete.Look at these links.http://www.buildingscience.com/resources/basements.htmI pull out all of the plastic, FG, and house wrap..
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
putting vapor barrier essentially between two walls (one of which being a notorious host for moisture) will always cause problems. i think the overuse of materials like tyvek,typar, etc are a trend that cause more problems than benefits. i never would have put anything behind the wall.
Typar isn't a vapor barrier.
Half of the harm that is done in this world is due to people who want to feel important. They don't mean to do harm but the harm does not interest them. --T.S. Eliot
sorry, not vapor barrier, anything that can trap water vapor.
Like drywall? Insulation?
Half of the harm that is done in this world is due to people who want to feel important. They don't mean to do harm but the harm does not interest them. --T.S. Eliot
the reason for the condensation is the fact that the wall can't breath. sheetrock and insulation are breathable. i realize typar is as well just not enough, in my opinion anyways.
You'll recall that the OP said the condensation was on the INSIDE of the Typar, between it and the insulation. The Typar had not "trapped" moisture coming out of the concrete.In fact, I kind of suspect that the OP may have misinterpreted this whole thing. If he breached the inside vapor barrier and didn't dig into the wall until later, moisture from inside the house could have penetrated the insulation and condensed on the cold Typar. And, were the Typar not there, it would have condensed on the masonry.
Half of the harm that is done in this world is due to people who want to feel important. They don't mean to do harm but the harm does not interest them. --T.S. Eliot
So which one is it ?
<In any event, "conventional wisdom" would suggest that it might be wise to remove or simply slit the vapor barrier on the bottom 2/3 or so of this wall>
or
<If he breached the inside vapor barrier and didn't dig into the wall until later, moisture from inside the house could have penetrated the insulation and condensed on the cold Typar.>
Geoff
Both. Depends on what conditions were present.
Half of the harm that is done in this world is due to people who want to feel important. They don't mean to do harm but the harm does not interest them. --T.S. Eliot
Your builder has created an incubator for mold behind your basement walls. The long-term problems with the construction method you have described are well documented. Unfortunately, your builder (and/or your local inspector) is not up to speed with current best practices for basement walls.
Simple physics dictates that water vapor will migrate from areas of high concentration (the surrounding soil), through your block walls, and be released to areas of low concentration (the interior of the basement). A block wall will not stop the migration of water vapor, neither will typar. A layer of 6-mil poly will slow it down, hence the condensation on the back side of the poly.
Proper basement wall construction methods require a vapor barrier (preferably foam board), directly against the masonry, with all the framing/sheetrock on the warm and dry side. Slitting the poly won't do anything, other than expedite the time it takes for the sheetrock to turn into a soggy mess.
Fortunately, the drywall isn't up yet. I'd be ripping this mess out and doing it correctly (or someone else will have to in a few years). There's an excellent article in the March 2005 issue of Fine Homebuilding by Andy Engle that you might want to review and share with your builder.
The relative humidity reading of the basement is needed in order to calculate the dew point temperature that the exterior wall surface would have to be to condense the water vapor into a liquid. I am sure that in your climate that wall is cold enough on a daily basis to condense most water vapor.
Typar is vapor permeable, but a liquid water barrier...and once the humidity is condensed to water neither the typar or the plastic will allow it to leave the stud cavity. Each daily cold/warm cycle within that wall will pump more humidity in to be condensed and trapped.
If your house has a higher than normal humidity and the interior of the exterior walls have penetrations that allow for migration of this vapor laden air into the stud cavity, it will then condense on the cold surface of the exterior wall.
You have a definite problem that will soon produce mold and rot in abundant quantities......have a professional analyse your house's environmental circumstance and apply an appropriate fix.......NOW!
...............Iron Helix
You're right, I believe the wrap was installed backwards, and it is supposed to be a "one-way valve" letting moisture out but not in, it's primary function is to prevent moisture laddened air from infiltrating the wall cavity.
Geoff
There's no such thing as a "one way valve" for housewrap. At best stuff like Typar has a fuzzy layer on one side that absorbs (or may absorb -- haven't checked into it) liquid moisture, but that has nothing to do with the passage of vapor. Planck's Daemon won't let such a thing exist.
Half of the harm that is done in this world is due to people who want to feel important. They don't mean to do harm but the harm does not interest them. --T.S. Eliot
Dan , I beg to differ, the original design and intent of Tyvek was to prevent water vapor from entering the wall cavity from the outside while allowing vapor that may get past the VB on the inside to escape to the outside atmosphere, hence the "fuzzy" feel to the inside face of the Tyvek or Typar. Consequently, that's why the OP had condensation on the inside of the wall, the Tyvek installed with printing to the inside allowed moisture to pass through into the wall cavity and of course condense on the coolest surface, usually the poly VB or possibly the backside of the Tyvek since it now will act as a barrier and is cooler than the insulation.
Since the OP said the rock had not been hung yet, I would tell him to get his insulation/VB inspection, then as soon as the inspector leaves rip off the VB and pull out the fiberglass and remove the Tyvek, had the Tyvek been installed face out(toward the masonry)to begin with, he would most likely not be having an issue now. As to the wet wood theory, that may have contributed to the problem as well, since again the Tyvek was acting as a VB as installed.
Geoff
Bullfeathers! Tyvek is first and foremost an air (not water) infiltration barrier. Tyvek has essentially the same "feel" on both sides, and which way you apply it is irrelevant to its function. (There is a very slight difference in "feel" that is due to the manufacturing process.)"13. Can DuPont™ Tyvek¯ be used with the lettering facing in?DuPont™ Tyvek¯ HomeWrap¯, DuPont™ Tyvek¯ StuccoWrap¯, DuPont™ Tyvek¯ DrainWrap™ and DuPont™ Tyvek¯ CommercialWrap¯ are equally effective in both directions. However, DuPont™ Tyvek¯ StuccoWrap¯ and DuPont™ Tyvek¯ DrainWrap™ have a specially engineered surface that should be placed with the grooves in a vertical direction."http://www2.dupont.com/Tyvek_Construction/en_US/uses_apps/builders/FAQ_builders.htmlTypar (which the OP says he has) is a coated fabric, and the coating is primarily on the "outside", but this has nothing to do with the passage of water vapor. It has more to do with protection from UV rays and the shedding of liquid water.It is a physical impossibility for a housewrap to be a "one way" product with regard to water vapor. You'd have to supply energy (ie, electric housewrap) to cause the water vapor to only move one direction.In the OP's case, the fact that there was condensation on the housewrap, and on the INSIDE of the same, suggests that the moisture involved was coming from INSIDE the house, or perhaps from the wood framing in the wall. At most it was moisture that got into the wall and then condensed when the weather turned colder. In a steady-state situation you would not see water vapor coming out of the masonry, going through the housewrap, and then condensing -- the temperature in the stud cavity is higher than that of the masonry (at least if the house is heated at all), and thus necessarily above the dewpoint.
Half of the harm that is done in this world is due to people who want to feel important. They don't mean to do harm but the harm does not interest them. --T.S. Eliot
Dan, from your link,
6. What is the difference between DuPont™ Tyvek¯ and black paper?Black paper or building paper was not designed as an air retarder like DuPont™ Tyvek¯. Unlike DuPont™ Tyvek¯, building paper can absorb water. Building paper tears easier than DuPont™ Tyvek¯ and can degrade over time when under continual exposure to water. Building papers are less permeable to moisture vapor transfer than DuPont™ Tyvek¯ increasing the potential moisture vapor trapped inside the wall could cause mold, mildew and rot.
7. What is the difference between DuPont™ Tyvek¯ and other housewraps?Many other wraps are perforated, which means in order for them to breathe, the manufacturer has punched holes in them, resulting in a reduction of air and water holdout effectiveness. DuPont™ Tyvek¯ is a non-perforated, nonwoven product with microscopic pores that are so small air and bulk water have a difficult time passing through but since DuPont™ Tyvek¯ is breathable, moisture vapor can easily escape from the wall.
Past the question of Typar being a "one way" membrane , if in fact the moisture was from inside the wall, why wasn't it escaping from the wall cavity,as stated above (#6 green highlite), secondly, if there indeed was moisture in the air on the block wall side it could in fact pass through into the wall cavity,since the Typar is not a one way membrane, where it would condense on the first cool surface i.e. the "front" of the typar,since it should not have passed beyond the insulation or it would have con densed on the inside of the poly VB.
If Typar is permeable as stated above why didn't the vapor escape?
Either way the use of the Typar or Tyvek on the "outside" of an interior basement wall is not a good practice.
<In a steady-state situation you would not see water vapor coming out of the masonry, going through the housewrap, and then condensing -- the temperature in the stud cavity is higher than that of the masonry (at least if the house is heated at all), and thus necessarily above the dewpoint.>
The temp. in the wall cavity is indeed higher than the masonry, but the Typar temp. is lower, making it the surface for condensation, and since the Typar doesn't let bulk water penetrate easily( see above in red) the moisture is trapped inside the cavity.
Bottom line for me is Typar,Tyvek, et. al. are not worth using IMHO
Geoff
> Past the question of Typar being a "one way" membrane , if in fact the moisture was from inside the wall, why wasn't it escaping from the wall cavity,as stated above (#6 green highlite)What says that it wasn't excaping from the stud cavity towards the masonry? Just because there was condensation, it doesn't say that water vapor wasn't escaping, just not fast enough to prevent the condensation.> if there indeed was moisture in the air on the block wall side it could in fact pass through into the wall cavity,since the Typar is not a one way membrane, where it would condense on the first cool surface i.e. the "front" of the typar,since it should not have passed beyond the insulation or it would have con densed on the inside of the poly VB. Water vapor in the air will condense when the temperature drops below the dew point. If water vapor was evaporating from the masonry wall that says that the wall was above the dew point temperature. Assuming that the house is warmer than the wall, there's no way that the moisture would then condense anywhere in the (warmer still) wall cavity (assuming steady-state conditions).Either the condensation seen by the OP occurred due to a relatively sudden drop in temperature, or it was due to moisture from the INSIDE.Now, I'm not defending the construction of the wall. Due to the vapor barrier it will tend to collect liquid moisture against the Typar, due to temperature cycling. But the Typar isn't at fault, just an innocent bystander. For basement walls some sort of foam is a much better choice.
Half of the harm that is done in this world is due to people who want to feel important. They don't mean to do harm but the harm does not interest them. --T.S. Eliot
agreed, foam is the best choice for basements!
Geoff
Not starting a fight but, I watch mythbusters way to much.
I took a two pieces of tyvek and put one label side out and one label side down and quess what? Label side up passed water at a slower rate. Go figure??
There is a mechanical effect when you actually apply water to the surface with any sort of pressure. Depending on the orientation of the strands they may be pressed tighter together or farther apart, resulting in a change in flow rate (which is vanishingly small in any event).The more appropriate (but much more lengthy) experiment would be to get two containers (say mason jars) and put equal amounts of water in each. Then cover one with Tyvek face up and the other with Tyvek face down. Place in a temperature stable location and wait to see how quickly the water evaporates out of each.
Half of the harm that is done in this world is due to people who want to feel important. They don't mean to do harm but the harm does not interest them. --T.S. Eliot
O.K.
I was just curious and did a quick check. Kinda fun!
My first home was circa 1917. Believe me, it was so drafty, it had perfect equilibrium.
When you're this good, EVERYONE wants a crack at you!
http://www.petedraganic.com/
What you've seen is common with most construction. While there is a poly barrier that by itself will not let water vapor by, small gaps along the edges of the poly barrier and any penetrations into the stud cavities are like super hiways.
One winter we stripped a house down to the clear poly barrier during the course of the remodel. The stud cavities were exposed, yet continued to function as they had when the house was occupied since we continued to run the furnace.
The fiberglass had dark paths stained throughout the exterior walls where either a leaky exterior outlet penetrated the tar paper, or a leak came from the interior, usually from a poorly sealed electrical box or loose section of sheetrock at the edge of the poly barrier.
First thing in the morning moisture would be condensed on the stud side of the housewrap (tar paper). As the sun hit the southeastern walls the condensation would switch and form on the interior clear poly barrier. This would continue around the house until the evening when all the condensation would return to the exterior surfaces. Very cool.
Beer was created so carpenters wouldn't rule the world.
Am I reading this right? It sounds to me like you are refering to finishing a basement. If thats correct, there shouldnt be any vapor barrier. The contractor should've just used rigid insulation and called it good.
You really dont want to trap any moisture behind the walls. It should be allowed to breath.