Insulating? framing?

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  #1  
Old 02-20-09, 09:33 PM
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Insulating? framing?

I recent framed my basement walls. How far should they be from the cement wall so i can put my insulation in without touching the wall ? after that I am putting vapour barrier on top is that ok?
 
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Old 02-20-09, 10:28 PM
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Half inch from the concrete is fine. Vapour barrier the top 4' if you wish. If you barrier the bottom you create a double barrier(foundation is either wraped or tarred).
 
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Old 02-21-09, 04:12 AM
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Old 02-21-09, 07:29 AM
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insulation question again

so your saying that I should vapour barrier my whole wall? Really confusing guidelines .....I just wanted to know if I am away from the wall and insulate with Roxul flexbatt which is a good insulation. That I Acustic seal the vapour barrier and I should have mold problems
 
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Old 02-21-09, 08:04 AM
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If stud wall is not touching concrete wall no VB needed.
 
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Old 02-21-09, 11:32 AM
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Basement insulation and VB placement *is* confusing. I think the reason is because of the various climates in various parts of the country, and to a lesser degree, whether the basement is actually finished, conditioned space or not.

In some parts of the country where frost and freezing is minimal, the ground temperature is usually close to 50-55F, and as such, it does not reach the dewpoint (as measured inside the home). However where I live, footings must be at least 42" deep. The wall could be 0F at ground level... it would be 32F at the frost line... and the gradually increasing to maybe 45-50F at the footing. Houses with CMU's likely also have cold air dropping down any hollow cores that have not been slugged. So during winter months, the actually temperature of a basement wall is usually well below what we think the normal ground temperature should be at that depth- 50-55F. When you are trying to keep the basement at 68F, this creates a potential problem with condensation- warm conditioned air meeting the cold foundation. (at least during winter months)

I really have no strong opinion either way, although I can report that I recently tore out some drywall in a basement. What I found was quite interesting. On the exterior walls (3/4" furring covered by a poly VB, with NO insulation) the poly was doing it's job. The back of the drywall was clean and dry. There was some moisture on the back of the VB (cold side) but none on the warm side. The soil and block on the cold side of the VB was moist, since cement and soil absorb moisture. The VB stopped the movement of this humidity into the home.

The interior block walls also had 3/4" furring... again, no insulation... and *no* VB. I assume that the builder felt there was no reason to have a VB on an interior wall. But on these walls with no VB, the back of the drywall was very moldy and was showing decay.

First, I was quite surprised to find no insulation whatsoever on these exterior walls. But I was even more surprised to find no mold on them. What was even more surprising, was that the mold WAS present on the *interior* walls that had no VB. Evidentally, it was because of the conduction of cold through the block where interior and exterior block walls met, coupled with the fact that cement has the ability to absorb moisture from the air.

Being a simple carpenter (not an engineer or specialist in this field) it would seem to make sense to me that if the temperature of an exterior wall should EVER fall below the dewpoint (as measured INSIDE the home) you would need to have a VB to prevent warm moist air inside the home from contacting the comparatively cooler walls.

So if I am framing a basement wall where there will be furring or framing over a cement surface, I ignore all the contradictory advice I have seen and read. Instead, I cover the cement wall with a VB (either poly or foam) leave a minimum 3/4" air space, then frame and insulate the wall using unfaced insulation.

I haven't had any problems with this method, but I also haven't torn out and inspected any of my work. I'll let you know what it looks like in another 30 years.

I'd also be interested to know how basements are handled up in Canada. Our winters obviously aren't as severe, but there are a few similarities. Our coldest temps are usually in the -20F's but thankfully do not last for very long or we'd have some real problems.
 
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Old 02-21-09, 08:08 PM
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Well this is what I ended up doing. I framed the basement and cause my cement walls aren't excaltly straight. I framed the walls so they are at least half inch away from the cement wall and then secured it to the above joists and drilled tapcons in the floor base of the framed wall then wired it and used a condoms around the electrical boxes then I am now going insulated the walls with Roxul flexbatt its like a green insulation that deson't burn, get wet or mold goes to this stuff its a good product. but I won't let the insulation touch the walls when putting them in the framed walls. then after all this is done VB the whole thing with a accoustic seal ( looks black ) and seal the whole thing in and out of the joists and that should be good
 
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Old 02-21-09, 08:36 PM
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VB will not do any good because of your 1/2 space behind the wall.
 
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Old 02-21-09, 09:36 PM
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Originally Posted by Lats2008 View Post
...and used a condoms around the electrical boxes...
Please explain the benefits of using the aforementioned items... I'm intrigued.
 
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Old 02-22-09, 03:28 AM
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Now, that is quite obvious! Who wants to wake up one morning to find that of the 6 receptacles you put in, you have 6, possibly 8 more showing up in odd places. It is just a precautionary measure.
 
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Old 02-22-09, 06:29 AM
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I know that when working with electricity, one should always be safe, but...
 
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Old 02-22-09, 07:24 AM
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lol ya;I know what you guys are saying but the condoms are are a so know air deson't get thru. But for the other guys why won't my VB work? I haven't put it up yet? Explain why? I can't put the wood framing against the wall cause of rotting the wood can happen but hmmm seem ok in the new best practice for Northern Ontario Climate. but please explain? I I wouldn have put VB on the cement wall then that creates moiture plus I haven't finished blue skin on the outside walls yet this summer finishing the other walls but I have NO water coming in the house and I know this house for 30years and yet to see water thru it. But Its a split Level house about 1100square feet. Please explain how i should have done it thats why I was asking earlier.
 
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Old 02-22-09, 08:18 AM
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Hi Lats, as for controlling the propagation of unwanted receptacles and air flow, Iím not sure your solution is designed to last that long. It might however serve to keep an application of spray foam from intruding into the box. I just had to comment on that one.

I sense you are looking for answers where none exist or at least the answers for one basement donít necessarily fit all others. For whatever you propose to do, I can find an article that says you are right and another that says you are wrong. One of the messages I was hoping to convey with the link I posted above was that years ago we never used VBís, then we thought they were needed everywhere, and now we are learning, all-be-it slowly, that VBís can be a bad thing. Especially when combined with our new very much tighter homes. You say you have never had a water problem in your basement, however water vapor has always been entering through the concrete ever since it was constructed. Since that moisture canít dry to the outside it has to dry to the inside. Thus the air gap you are leaving. The second source of moisture is the humidity inside your home, especially after you finish everything and add heat. If any of that moist air reaches the cool/cold wall behind your framing it has the potential of condensing out. That may occur in the summer rather than the winter. By omitting the VB and dehumidifying in the summer you will reduce the risk of condensation and provide a path for moisture to escape.

I know this doesnít give you a specific answer, as I donít have one, my learning is still work in progress and the subject of basements doesnít have a specific answer. I will follow the thread to see what you choose. I am also interested in the ďRoxul flexbattĒ you mentioned as I have never run into it where I work. Good Luck.

Bud
 
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Old 02-22-09, 11:44 AM
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Here again, it may not work for your area, but if you are using kraft faced insulation, there will be no need for additional vapor barrier. Save some money. Others may have more local advice.
 
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Old 02-22-09, 12:34 PM
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I did forget to mention that my outside walls are partly done with a blueskin protection plastic. Also with a yellow drainage board that protects the blueskin. That wall is as dry. So when framing the basement and when its done. In the summer I will digging the other walls outside and cleaning them and purge the walls and change my weeping tile. Which then I would prime the walls and then add the blueskin and seal the joints and put the yellow drainage board on. So after thats done I fill the hole with crush rock the Geotecile and then fill the rest of the whole with B-grade sand pit. And not the dirt was there. Its a better way of drainage and water filtering to te weeping tile. Then the walls will dry up and stay dry. I bin reasearching and I can find anything that would make what I am doing wrong ? Seems everyone is doing it my way unless there buliding a new home then there are other methods. thanks hope this helps and more information comes back. Northern Ontario I live so cold here hehe. but also really warm in the summers.
 
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Old 02-23-09, 12:39 PM
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Might have a problem now? Help

. But I found something that I am not sure of yet. I insulated my walls and haven't gotten to the Vapour Barrier yet. So I was trying to decide to VB the walls yet or wait till summer when I finish the outside walls using the blueskin. Anyways i decide to check underneath the upper walls behind the insulation and pull it away and I notice that the upper 4feet was were damp and wet. with frost. So I left the insulation off for now. Would it be ok to insulated it and VB the walls and will keep the hot air out and then the walls will dry? Or should I wait? Reason is that I am finish the outside walls this summer. Or would it not hurt anything bye finishing the walls ? my framing is not touching the walls so mold won't be able to go. Any suggestions please help. Thanks
 
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Old 02-23-09, 12:53 PM
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The VB will only make things worse because there will be even less air movement.
 
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Old 02-23-09, 07:50 PM
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Sorry Airman your wrong. I research it and found the reason why my walls started to sweat is because when I insulated to the point were the hot/warm air still can reach behind the cold wall it started to sweat. when I didn't have the insulation there it was ok. So this time when I re-insulate the walls I have to Vb right away to contain the same temp air flow between the walls so that it deson't sweat. We proved it in our area to find out it it was why this happened to me. I was correct cause the VB was put on and sealed. so that it keeps the warm air out. Reason cause I insulated the wall that has the Blueskin on outside wall already and it didn't sweat at all. not even a drop of condensation. so conclusion to this that as long as my framing is away from the wall which they are for airflow and warm air deson't get in then .......I am good to go. And on top of this when I finish blueskinning the rest of the walls the remainder of the what ever moisture is there will dry up like my other wall. So slowly but surely I am learning and finding why and how it works. As for mold growing as long it deson't have a organic present it won't if at all. interesting how easy this works. Specially using that Roxul insulation that deson't burn no absorb water and mold prof. This stuff hold R-value like really good, besides spray foaming. Anways let you know how my walls turn out. So far so good
 
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Old 02-24-09, 10:33 AM
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"No Colonel Sanders, you're wrong", Bobby Boucher, Waterboy, 1998.
 
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Old 02-24-09, 01:38 PM
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When I send the pictures and the scientic facts to you then you can tell me if I am wrong plus why judge me when I live in Northern Ontario and the material i am using with the advice for pro's here now that they have did it this way and it is successful, Water boy that ? stickboy Unbelievable the sarcasim that you guys give here when I was only simple wanted some help and advice and you give nothing but nothing to me including the plug vb i used and I called them condoms....gee thanks for the help.
 
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Old 02-24-09, 05:27 PM
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Originally Posted by Lats2008 View Post
lol ya;I know what you guys are saying but the condoms are are a so know air doesn't get thru.
lol, just kidding you Lats2008. I had never heard of the "condoms" for the electrical boxes, it sounds like a very good idea to keep cold air out.

Overall, I think you're getting good advice... no one is making fun, I think spackle was making reference to a quote from a 1998 motion picture called "The Water boy", maybe your comment to Airman reminded him of it... but I can't say for sure. I'm sure no offense was intended.

Ultimately, you need to pick and choose what advice you listen to here. None of us live as far north as you do, so many of us can only comment on what works where we live. Be patient with us and we'll try to learn from one another.

The Roxul insulation you are using sounds like good stuff.
 
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Old 02-25-09, 08:47 AM
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ok thanks Xsleeper I appreciate your comments. Thanks again
 
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