Replies

1. 
   Sphere | Sep 09, 2005 05:15pm | #1

   Depends.

   Is it a wall getting the brunt force of weather?

   I'd go with 30lb felt . Or nothing, if the SIP's are alrady your VB.

     Spheramid Enterprises Architectural Woodworks

2. 
   BillBrennen | Sep 09, 2005 06:52pm | #2

   Jon,

   It has been my understanding that 15# felt breathes a lot better than the 30# felt. Both felts have a proven track record for durability over a century. Modern housewraps have yet to prove themselves equivalent, and cost more money. I'd use the heavier felt if the SIPS are sealed tightly against air movement through them.

   Using the 1/4" strips over the felt is very good, as it creates a rainscreen that drains well and allows the back of the siding to air dry after a storm. By breaking the capillary bond, the 1/4" space reduces leaks through any holes in the felt by letting it drain away instead of hanging out between the two touching surfaces. Strips of rolled roofing or similar stuff will not rot away as plywood could do.

   Bill

3. 
   BillHartmann | Sep 09, 2005 10:43pm | #3

   " I need something that will breathe"

   Define "breahing".

   And why do you want it in this case?

1. 
   JonE | Sep 10, 2005 12:59am | #4

   Always assumed that I had to have a "housewrap" of sorts behind siding.  Also assumed that the face layer of OSB on the SIP needs to be able to dry out if wet.  My initial inclination was to use felt paper.  I may be on the right track. 

4. 
   DanH | Sep 10, 2005 03:25am | #5

   If you've got SIPs you don't need an infiltration barrier, so anything that serves as a rain barrier will do. Breathability isn't a big issue (especially with felt, since the lapped seams will breathe enough).

   Of course, behind Hardiplank you really shouldn't need a rain barrier either.

5. 
   MRinger | Sep 10, 2005 05:09pm | #6

   Home Slicker Plus TYPAR.

   http://benjaminobdyke.com/html/products/slickplus.html

1. 
   JonE | Sep 10, 2005 05:58pm | #7

   Perfect.  'Zacktly what I'm looking for.