Replies

1. 
   xMikeSmith | Sep 27, 2002 11:53pm | #1

   they usually figure R1 to the inch for  framing lumber.. so, since there is a lot of variation i figger R4 for a 2x4 on edge.. and R6 for a 2x6 on edge.. naturally you can see that the framing really degrades the total R-value of the wall...

   this is especially apparent if you have ever looked at a thermograph of heated wood frame buildings on a cold day...

   Mike Smith   Rhode Island : Design / Build / Repair / Restore

1. 
   whancock64 | Sep 28, 2002 07:03am | #3

   Have you heard of staggered studs walls. We built some for a church for sound

   proofing with thick batts between the walls. It was pretty cool, but WOW

   what a cost. They wanted the chior room to be able to be used for kids while regular church was going on too. It at least doubles the framing cost of each wall. Had 2x8 top

   and bottom plates with the studs spaced at 16 oc, but the inside studs were

   on the inside edge of the plate and the outside were on the outside edge.

   They also were staggered so that the inside and outside studs fell at 8"

   intervals.

   That make sense?

   Looked like this from the top, sort of, I'm no artist...

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   Bet that would be the holy grail for thermal insulation too, you think? I want to build a place for the mountians and was considering 2x6 for better insulation space, but after thinking of this I might spend some of my DIY savings on this.

1. 
   xMikeSmith | Sep 28, 2002 02:56pm | #4

   we've built 'em all.. staggered double studs.......... 2x6...........foam insul outside .....foam insul inside...2x4 outside wall w/ 1"air space and 2x3 inside wall...

   my  favorite energy wall is dens-pak cellulose  2x4 @ 16" OC.. with 1" EPS Performguard foam on the inside (2# / cf density)  and horizontal furring at 16" oc ..with electrical devices in 4" boxes with 1.5" plaster guards

   our standard wall  nowadays is 2x4 with dens-pak cellulose..but if there is electric heat , we usually recommend the energy wallMike Smith   Rhode Island : Design / Build / Repair / Restore

1. 
   BillHartmann | Sep 29, 2002 07:59pm | #5

   Mike

   What is the reason for using the Rerformance guard on the inside or do you use it just because that is your "standard".

   Also is it available with an metalic surface? I thought that part of your system was using a metalic surface against the furring strips as a radiant barrier.

1. 
   xMikeSmith | Sep 29, 2002 09:00pm | #6

   the metalic surface can be had ( I guess ).. but i never spec it.. we used to use foil-faced poly-iso.... but after going back to some old jobs and finding the foam full of larvae, carpenter ants , etc.. we only use Performguard now..

   I'm one of those guys that think radiant insulation is way overrated.......

   as to using it on the inside... ther's a couple reasons...one is the plywood has to be in contact with the studs to get the full shear value.. so the foam can't go there.. 2: there is too much labor providing blocking for exterior trim if you use foam on the exterior 3: the foam is a pretty effective vapor barrier.. so it belongs on the interior rather the exterior where it might trap moisture trying to exit the structure...

   consider the source though.. we build in a 6000 DD climate.. so heat is our primary concern.... in  cooling territory you have to have a different strategy

   Mike Smith   Rhode Island : Design / Build / Repair / Restore

2. 
   CloudHidden | Sep 28, 2002 12:35am | #2

   http://hem.dis.anl.gov/eehem/99/991110.html