Do they make 12" wide insulation anymore??

Reply

  #1  
Old 01-31-14, 10:08 AM
Home wrecker's Avatar
Member
Thread Starter
Join Date: Apr 2007
Location: Rochester
Posts: 379
Received 0 Votes on 0 Posts
Question Do they make 12" wide insulation anymore??

The joist in my basement crawl space are only 12" apart. The ones in the full part of the basement are 14" apart. They used to make 12" roll insulation but I can't seem to find any. I suppose I'm looking at buying 24" and having to cut it down the middle on every piece. That is going to be a major pain.

Another question about crawl spaces. I understand a vapor barrier should be put down over the dirt floor. Is there some reason the plastic has to be 6 mil thick? There is tar paper in there now. The dirt floor is about 15X20. If I buy the 10'X100' roll it's $60, but then I have a seam. The 20'X100' is $100, but then I have a bunch of plastic left over. Can I use that to cover the exposed insulation in my wood shop, which is also in my basement??

If I do the (crawl space) ceiling and the vapor barrier then do I have to do the walls to make the project work? Money is kinda tight so I'm trying to do this on a slim budget.
 
Sponsored Links
  #2  
Old 01-31-14, 10:41 AM
Group Moderator
Join Date: Oct 2004
Location: WI/MN
Posts: 19,308
Received 47 Votes on 44 Posts
The seam is fine, you can tape that. You would want to run the poly up the walls about a foot and tape it to the wall.

You're talking about insulating the ceiling - this crawlspace is vented to the outside and sealed from the house air, right?
 
  #3  
Old 01-31-14, 11:05 AM
Home wrecker's Avatar
Member
Thread Starter
Join Date: Apr 2007
Location: Rochester
Posts: 379
Received 0 Votes on 0 Posts
Hi Mitch
The crawl space isn't open to the outside, there is a window, but it has been sealed shut. It opens into my wood shop through a hole that is 2'X2'. It's where the outside of the house used to be and there was a window there at one time. The previous owner built on an addition to the house. The crawl space tapers from about 2 1/2' high down to about 1' at the far end. What kind of tape, duct tape or is there something special they use? I saw in one post where they put sand on the plastic right at the walls edge to hold it. Taping it makes more sense. There is also a musty smell, no mold, just smells like really old dirt. Will I have to put something on it to get rid of the smell or will the plastic do the job?
Is my only option on the ceiling part to cut 24"? I will also have to cut the wires that hold it in place too. Is that a cut in half too? I got a box of the 15" ones for the main part. That is what I'm working on now. Crawl space is next. Really not looking forward to that part of the job.
George
 
  #4  
Old 02-01-14, 07:50 PM
Member
Join Date: Jan 2014
Location: usa
Posts: 466
Received 1 Vote on 1 Post
12" wide insulation

Although 12" insulation is made it can be somewhat difficult to get. I would suggest you call an insulation sub-contracting firm and ask them if they can order it from their suppliers. Sometimes the major manufacturers won't run it unless they get a special order for a large quantity like a full trailer load, then they may have an overrun and have available. An insulation sub would also likely be able to get the 12" wires because they are also made.

The poly vapor retarder can be overlapped and taped. Vapor barriers work relative to the amount of surface area they cover so you don't have to get too nuts about sealing them up like you would a pail of water with a hole in it.

The smell you are sensing MAY be relative to the old building felt on the ground. Old versions of these products were made from an organic fiber mat saturated in asphalt and organic fibers can decay over time in contact with the ground. New felts are more often an inorganic fiber saturated in asphalt.
 
  #5  
Old 02-02-14, 07:26 AM
Home wrecker's Avatar
Member
Thread Starter
Join Date: Apr 2007
Location: Rochester
Posts: 379
Received 0 Votes on 0 Posts
Hi Calvert
I'm a bit confused. The last few days I've been looking at videos of how the deal with a crawl space. I am not a contractor so I am not familiar with the terms like conditioned or unconditioned space, vented or unvented space.
I have a heat duct that runs the length of the space. It's about 20' long. The space, like I said above, is open to my wood shop though a 2'x2' space. Actually there is another space down by the furnace where the duct and the furnace pipes come through the wall. That space is about 2 blocks wide by the height of the block.
So, starting over with this conversation.... Where exactly should I be putting the insulation, on the walls or the ceiling? And, should I be putting insulation on that duct pipe. It provides heat in the winter, air conditioning in the summer. The last thing I want to do is create a moisture problem. Now I'm reading that the 6 mil plastic really isn't enough, it should be 12 - 20 mil. This space is simple a crawl space. It's not used for storage, at least the back part isn't. The dirt on the floor part is all little mounds. I assume I have to rake that out level. Also yesterday I noticed that in the back part someone has dug the dirt away from the foundation. There is like this little ditch about 6 inches deep? It's dry so should I fill that back in or is it there for some reason? It may have be done when they put the furnace in. The pipes from the old furnace (venting outside) were only 2". I guess code says they needed to be bigger, that or the contractor just felt like screwing me over. It's pretty tight down at that end so I can't imagine why anyone would want to go down there.
If I should be doing the walls, which is better, the foam board stuff or the roll blanket??
I just want to get this done, my heat bill is insane.
George
 
  #6  
Old 02-03-14, 05:04 PM
Member
Join Date: Jan 2014
Location: usa
Posts: 466
Received 1 Vote on 1 Post
Home Wrecker, As you can well appreciate, doing a proper analysis is difficult without seeing the situation first-hand. Also, there is not always just one proper approach to doing things although some are better than others.

A conditioned crawl-space would entail the use of insulation on the perimeter foundation walls. This can be accomplished in several ways but the least acceptable would be the use of fibrous batt materials. Sealing the rim joist and top of foundation (if it is open block) would also be an important aspect of doing the job correctly. Using a foam board with an R-value as high as the pocketbook can afford makes sense. Check your local code to understand what is required for fire resistant facing on the insulation.

The vapor barrier is still also critical and 6 mil poly is acceptable but if you want to go heavier....no problem. I frequently use rubber roofing as a vapor retarder, it goes down very easily and creates a much better surface to slide around on if you have to get in there to do anything. You can sometimes get pieces from a roofing contractor who is replacing a job for reasonable $$$ or sometimes free. Getting the lightest weight (usually 40 mils) is more than you will ever need from a vapor transmission standpoint but as I said it does roll out very nicely.

The duct work should at the very least be sealed at the joints regardless of any other approach to insulating the space. This just makes good sense for any air system as it makes balancing the assembly more meaningful. The duct work should also be insulated, check local code for R-value but it should be min. 8.
 
  #7  
Old 02-03-14, 05:21 PM
Home wrecker's Avatar
Member
Thread Starter
Join Date: Apr 2007
Location: Rochester
Posts: 379
Received 0 Votes on 0 Posts
Calvert
Good and thanks, maybe tomorrow I can do some of the duct work stuff. I have a bucket of mastic and reenforced mesh joint tape. Will need to get some insulation though. When you say rubber roofing, what do you mean? Roll tar paper or ice sheild? There is some tar paper in there now and it's been there since way before we moved here. The guy next door said he helped put it in there about 20 years ago.
George
 
  #8  
Old 02-03-14, 07:19 PM
Member
Join Date: Jan 2014
Location: usa
Posts: 466
Received 1 Vote on 1 Post
Rubber roofing as used on flat roof commercial structures. Millions of sq.ft. go down every year in new installations. Much of the old material is fine, usually they start replacing the whole roof when leaks show up from seams or flashings at pipe penetrations.

In my area I can buy the 40 mil material new from a commercial roofing distributor for about $ 200.00 for a 10'x50' roll. If you call a few commercial roofing installers they may sell you some large pieces from a tear-off they are doing. This is not the same as the old roofing felt you have in there now. It is like the rubber you might see in an old inner tube.
 
  #9  
Old 02-04-14, 11:40 AM
Home wrecker's Avatar
Member
Thread Starter
Join Date: Apr 2007
Location: Rochester
Posts: 379
Received 0 Votes on 0 Posts
I know a guy who does roofing, he did mine a few years back. He owes me a favor. He got sick and couldn't do my shed which was part of the job I paid for. I'll bet he's got some or at least maybe can get some this summer. That sounds better than 6 mil plastic LOL.
 
  #10  
Old 02-05-14, 10:43 AM
Group Moderator
Join Date: Oct 2004
Location: WI/MN
Posts: 19,308
Received 47 Votes on 44 Posts
You insulate the ceiling of a crawl space which is sealed from the house and open to the outside but if the crawlspace is open to the conditioned air of the house and sealed from the outside then you insulate the walls.
 
  #11  
Old 02-05-14, 10:51 AM
Home wrecker's Avatar
Member
Thread Starter
Join Date: Apr 2007
Location: Rochester
Posts: 379
Received 0 Votes on 0 Posts
Hi Mitch
So, if I understand this correctly; if the exterior side of the walls are not sealed on the crawl space walls then it is a mistake to insulate the inside walls. '
The space is open to conditioned air: my understanding of that term means it is open to a warm basement. It is, so that means I don't insulate the ceiling either? The space is cold. My plan was to just put down some plastic on the floor and insulate the heat duct and the cold air return. Is that the right way to go????
 
  #12  
Old 02-06-14, 11:15 AM
Group Moderator
Join Date: Oct 2004
Location: WI/MN
Posts: 19,308
Received 47 Votes on 44 Posts
Not sure I'm following everything you say, so let me try it this way:
Your crawlspace is open to your house air so you need to think of it as just another room in your house when it comes to insulation - you want to insulate the surfaces which contact the outside. In this case, that's the walls (outside walls, not any which are against the basement). The ceiling is against house air in the room above it so you do not insulate the ceiling. That make sense?

And, either way, vapor barrier on the floor.
 
  #13  
Old 02-06-14, 02:10 PM
Home wrecker's Avatar
Member
Thread Starter
Join Date: Apr 2007
Location: Rochester
Posts: 379
Received 0 Votes on 0 Posts
Ok now I got it. I think I'm going to throw some insulation on those ducts too.

Dumb question: Do all of these new furnaces give off a blast of cold air when they first kick on? Why do they do that? OR Is it the cold air already inside the duct that I'm getting. Gotta tell ya, you don't want to be sitting in front of the sucker when it first kicks on. The air coming out feels like it came right off a polar bears butt. It get warm after a few seconds, but then I have that cold air I've got to reheat again. Not too cost efficient.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: