Replies

1. 
   MikeSmith | Mar 27, 2009 09:28pm | #1

   no

   Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore
1. 
   jonblakemore | Mar 27, 2009 09:31pm | #2

   Mike,Are you concerned about vermin or vapor? 

   Jon Blakemore RappahannockINC.com Fredericksburg, VA

1. 
   MikeSmith | Mar 27, 2009 09:43pm | #3

   vermin,  vapor,  nailbase  under  the foam  instead  of  on  top  of  the  foam,

   lack of  blocking  for  trim........

   exterior  foam  sucks

   'course,  that's  just  my  opinionMike Hussein Smith Rhode Island : Design / Build / Repair / Restore

1. 
   blownonfuel | Mar 27, 2009 10:22pm | #4

   Thanks for the input Mike.

2. 
   jonblakemore | Mar 27, 2009 11:24pm | #8

   To be a devil's advocate (or maybe just a pain), he could use borate treated EPS (vermin), EPS has a perm rating of 2-5 in 1" thick and he's in a cooling climate so a VB on the exterior may not be a bad thing, and Hardie says you can install their siding over 1" foam.'course, that's just my opinion. 

   Jon Blakemore RappahannockINC.com Fredericksburg, VA

1. 
   MikeSmith | Mar 27, 2009 11:28pm | #9

   Hardie  says  a  lot  of things  i disagree  with..

     they  are  marketer's  trying to  expand  their  market

   for  instance...  they  want  a  2"  gap  between   the  bottoms  of  their  siding  and   any  horizontal  surface

    

     way  excessive

    

   also.... there  is a  ton  of  trim  on  an exterior

    attaching  trim  over  foam  with out  blocking  is  asking  for  troubleMike Hussein Smith Rhode Island : Design / Build / Repair / Restore

2. 
   DaveRicheson2 | Mar 28, 2009 05:55pm | #13

   But mike, if he takes the advice you gave me it can work.

   You advised me to install blocking before the foamboard.  Although it is additional labor and material it worked out just fine. I even added a layer of house wrap over the blocking  as a weather barrier and tapped it to the foam board.

   It is now ready for the trim and feel comfortable with the weather tightness  and added insulation value I have achieved. The windows were set on the blocking so everything will plane out to a normal siding install.

   To the OP.

   You will also need to add interior jamb extension to both doors and windows.

3. 
   blownonfuel | Mar 28, 2009 06:02pm | #14

   Thanks guys for all your input.

4. 
   user-201496 | Mar 28, 2009 08:36pm | #15

   If you have any window or door leaks the water will get trapped between the foam and the OSB and will cause a major rotting problem very similar to the EFIS problems that are still on going. In my opinion, every house will have leaks from time to time so you want to plan for a way to drain the water and allow it to breath to dry out.

5. 
   blownonfuel | Mar 28, 2009 10:08pm | #16

   Thanks T.

6. 
   DaveRicheson2 | Mar 29, 2009 12:21am | #17

   Wrinkle wrap behind the foam and over the blocking for windows, doors, and trim.

   My garage has been sitting since last December, just that way. Windows and doors are installed and properly flashed. I have kept a close watch on the sheating, windows and doors from inside all winter. we have had some pretty good wind driven storms durring that time. Thus far there are no signs of any leaks.

   I think his idea is doable with carefull detailing

7. 
   user-201496 | Mar 30, 2009 09:19pm | #18

   I had an EFIS home and I am a builder. I can tell you that all homes have small leaks from time to time that you'll never see or notice. But if water gets trapped you will have rot and maybe termites and the resulting problems may not show up for many years.

8. 
   DaveRicheson | Mar 30, 2009 11:54pm | #19

   My foam is a minimum of 8" above grade on a concrete foundation. I used a tern flashing beneath the house wrap and stepped out and down over the foundation wall. My goal was to have a continouse drainage plane behind the foam and create a termite shiled at the lower edge. Of course there is no such thing as a temite shield, but at least it forces the little buggers to build thier mud tunnels out where you can see them.

   As far as all houses developing leaks. That is a possibility that depends a lot on the care and skill of the builder IMO. Thing don't just happen over time. Something fails or was not right to start with.

9. 
   user-201496 | Mar 31, 2009 01:09am | #20

   Well when a house goes through a storm event: hurricane, noreaster, etc. then you will probably have some water pushed uphill and into places you never thought of. Thats what I mean when I say all houses will leak somewhere sometime.

   Edited 3/30/2009 6:29 pm ET by T White

2. 
   CapnMac | Mar 27, 2009 10:35pm | #5

   rigid foam insulation over my osb sheathing (with felt) and under hardi? Being in Texas would it help

   Done all the time just up the road from you.  Have not been enough in Travis or Williamson Cos. lately to comment on practices therein.

   It's usually the sheapest way to pass ResCheck using a stock plan.  And, in the massive thermal gain climate we are in, a thermal break on the outside of the framing makes a great deal of sense, too.

   Occupational hazard of my occupation not being around (sorry Bubba)
1. 
   blownonfuel | Mar 27, 2009 10:39pm | #6

   Thanks Cap.

3. 
   EricPaulson | Mar 27, 2009 11:06pm | #7

   Google: Read This Before You Design BUild or Renovate. It has assemlies such as you describe. There are many other publications that deal with this, some you will have to buy.

   buildingscience.com

   I think foam outside of the sheathing creates more problems than it is worth in R value.

    

4. 
   cic317 | Mar 28, 2009 02:46am | #10

   Done all the time here in NY. Did 3/4 " Tuff-R w/ Hardi 4+ years ago on mine, No problems,Just pay attention to all flashing details!!! Get the extra R value Oil not getting cheaper down the line

1. 
   EricPaulson | Mar 28, 2009 02:54am | #11

   NY is NOT Texas.

   Totally different. 

1. 
   cic317 | Mar 28, 2009 02:59am | #12

   Thanks for clearing that up