Timber Framers Guild Forums General Straw Bales & Other Enclosure Systems housewrap and natural enclosure systems

I'm wondering what everyone think about housewrap and natural enclosure systems. For those who have infilled behind wood sheathing or siding, what type (if any) of building paper did you use? I'd sort of hate to throw up tyvek, but since I'm kind of locked into using osb sheathing (its available in the 10' sheets that I need, it'll keep the weather out while I get my act together, and its pretty cheap) I'm not sure what to put over it. 15 lb. felt is of course an option, though I'm not sure I'd be better off for using it. I guess not all sheathing would necessarily need covering, though 1/2 osb definitely won't last long unless covered promptly. Suggestions?

I'm a fan of 15 lb felt. It has a longer track record and is much more forgiving than tyvek or typar. Check out:

http://bct.nrc.umass.edu/index.php/publi...ation-barriers/

and read everything at:
http://www.buildingsciencepress.com/

One thing to keep in mind with Tyvek, it will break down when exposed to UV light. I don't know how much time you need to "get your act together" but the Tyvek can only handle 120 days of sunlight exposure so you time will be limited.

This being my own house, I don't necessarily know how long until I get my act together myself, but I have heard of UV being an issue with tyvek. Thanks for the reminder.

Any thoughts on detailing board siding for longevity and weather-tightness. I'm familiar with applying them over strapping, though some seem to feel that horizontal strapping is not ideal because it does not drainage or as much air flow. I suppose I could apply the shiplap over a vertical 1x4. I was planning on running profiled batten strips over the shiplap joints-- partly just for looks. I figure a redundant layer can't hurt anything.

I'm planning to let the board weather rather than paint. I can always stain or oil in the future if it proves to be problematic.

-Devin Smith
Rockingham, VT

Put a batten (even 1/2) under the board seams (reverse board and batten with no space). You can even use green boards that way, no shiplap necessary.

Depending on how much rain you get, Tyvek has a "Drainwrap" which has channels to help water drain and keep the back dry. For heavier/wind driven rain areas, look at is "Home Slicker". It is a rain screen mesh that provides airflow behind the siding to help it dry out. You can even get it alone if you are using felt, or already bonded to Typar building wrap so it all goes on at once. Might be a quicker/easier option over installing all the battens/strapping.

I also recommend back priming the siding to protect the back side of the siding from moisture damage. Even if you let the exposed face weather naturally, you want to protect the back from moister as it will take longer to dry out even with at rain screen. You can paint/stain the exposed surface later, not so easy on the back side. Good luck

http://www.nationalhomewarranty.com/NewPDF/ACCEPTED_RAINSCREEN%20DETAILS-4_July-2007.pdf

Canadian Rain screen info