Replies

1. 
   Piffin | Jul 21, 2006 06:16am | #1

   I lot depends on what part of the country you are in. That remains a secret in youir profile.

   Sorry to say, but you wasted money using bubble wrap under the slab if you wanted insulation. makes a fairly decent moisture stop though.

   top gain from the radiant aspect and come anywhere close to claims about R-value, the stuff needs a min one inch air space in front of it.

    

    

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1. 
   badarse | Jul 21, 2006 07:42am | #2

   No. cali foothills. It was 103 degrees today. Winter time, no snow, lows usually not lower than mid/high twenties.

2. 
   DaveRicheson | Jul 21, 2006 04:21pm | #3

   I've already sided the outside.

    

   What did you side it with?

   I see thermal bridging as more of a issue in cold climates, but can see that you could be adding to your cooling load because of it.

   You might also do a search for the " Mooney Wall" on this site. I have not built one, but darn if the concept doesn't make a lot of sense.

    

   Dave

1. 
   badarse | Jul 21, 2006 06:39pm | #5

   Definitely cooling load is the critical one here. That wall gets allota direct sun.

1. 
   paul42 | Jul 21, 2006 06:54pm | #6

   bright white paint makes a big difference.

   put in some plants that will shade that wall?

3. 
   frenchy | Jul 21, 2006 05:53pm | #4

   badarse,

        Thermal bridging is there whereever you have a 2x4 or 2x6 in the wall. the R value of one of those is about 2 while the R value of foam is about 5 or 6 per inch (depending on type of foam)    At absolute best a wall is only 80% of it's rating.. if you add double studs like at the top plate or around windows and doors etc. or any place you need to carry extra load the actual thermal rating goes down accordingly.   

    If you build without  studs as in homes made from SIP's or ICF's there is no thermal bridging.  

1. 
   andy_engel | Jul 21, 2006 06:58pm | #7

   Well, there is less thermal bridging. You'd need a vacuum to get no thermal bridging.Andy

   "Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein

   "Get off your dead #### and on your dying feet." Mom

1. 
   frenchy | Jul 22, 2006 06:13am | #9

   Andy, 

       While you may be technically correct your comment would seem to dismiss the real benefits of SIP's and ICF's.  Since I don't know of anyplace that uses a vaccum for wall insulation with todays available technology SIP's And ICF's offer the absolute best available insulation.

   '

1. 
   andy_engel | Jul 22, 2006 04:43pm | #11

   No, I don't mean to dismiss the benefits of ICFs and SIPs. They're both excellent products, and they reduce thermal bridging. I'm just being a stickler for accuracy. Overstating the benefits of any product ultimately reduces the credibility of those hawking it.Andy

   "Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein

   "Get off your dead #### and on your dying feet." Mom

1. 
   frenchy | Jul 22, 2006 08:53pm | #14

   Andy,

     Mine wasn't an overstatement, rather a simple explaination of benefits.   Granted not  a total in depth complete discussion but rather a simple brief statement of benefits..

     Solid wood has a high thermal bridging number while foam has a low thermal bridging number.   About 15 times if we simply compare R values.  

4. 
   hammer1 | Jul 21, 2006 09:25pm | #8

   I'm in the Northeast where cold is the issue. I've done many homes with 1" foam board under the sheetrock. Installing the sheetrock takes longer screws, I'd recommend installing blocking for kitchen cabinets. Windows and doors will need extension jambs. Electrical boxes will need to be mounted for the extra thickness of the wall covering. Trim install will take longer nails. The foam adds 5 points of R value, covers thermal breaks so you have a homogenous insulation surface and really helps to quiet the house. I used it on my own home when I built 25 yrs. ago, exterior walls and ceilings. Best insulation technique for the money and easy to DIY.

   Beat it to fit / Paint it to match

1. 
   Taylor | Jul 22, 2006 12:44pm | #10

   Do you bring the blocking for cabinets out to the same plane as the foam? I'd worry about 1" of bare screw in the foam, that's quite a bit of shear stress.

1. 
   hammer1 | Jul 22, 2006 05:43pm | #12

   I often hear people worry about attaching things with the foam. Since it's sandwiched between the stud and the sheetrock, and anything, like a cabinet, is pulled tight to that, there isn't an issue. The only difficult part is putting your screws in straight. They are longer than normal and can't be "horsed" in the way they normally get done. As long as you and a couple of big friends don't do chin ups on the cabinets, you won't have a problem. I keep the blocking flush with the framing. Crown moldings take a little extra care because of the long nails. I recently installed a shelf type crown in a back bed room and used some EZ-anchors rather than long nails, (poor picture). The homogenous insulation makes a big difference in energy savings and it makes the house very quiet. With the windows closed, you won't hear much outside noise.Beat it to fit / Paint it to match

   
2. 
   frenchy | Jul 22, 2006 08:49pm | #13

   Taylor,

       With SIP's you increase the number of fastners to decrease the load per fastner. It's the same principle used by airplanes.. many, many, tiny weak rivets make one really sturdy structure..