Seattle siding – Rain-screen 102
Seattle siding, rain-screen is not 1 size fits all.
Hopefully you’ve read my earlier post – “Siding Seattle – rain-screen 101” and have a basic understanding of Seattle siding rain-screen systems For this post I will get a little more in depth regarding the different types of rain-screen Seattle siding For the purpose of this post we’ll assume the drain plane to be vertical battens that the Seattle siding will be fastened to There are basically 2 different Seattle siding rain screen systems that can be employed They are: closed rain screen siding,? open joint rain screen siding.
Once a closed rain-screen Seattle siding job is done it doesn’t look any different than a traditional siding job The difference of course is there is a drain plane behind the Seattle siding and plenty of venting to allow the wall to dry out if and when water gets behind the siding.
An open joint rain screen is a Seattle siding system comprised of? planks or panels where there are open joints between courses You can actually see behind the Seattle siding to the weather resistant barrier (wrb) As you have probably guessed the wrb in an open joint rain-screen needs to be very robust as there will be water present whenever there is precipitation The wrb is also exposed to the sun and needs to be stable under ultra violet light exposure Right now there’s only a few wrb products on the market that claim they are UV stable and appropriate for open joint Seattle siding rain 
screens The product we use for this application is Vaproshield. It comes in black and needs to be doubled up where the open joints occur to protect from the UV light In practice this requires a double layer of the wrb when using narrow planks for your open joint Seattle siding rain-screen and secondary strips at joint locations when using wide panels for your open joint rain-screen The battens also need to be appropriate for water contact and stable under UV exposure.
Open or closed Seattle siding, rain-screens make sense.
Both of the rain-screen Seattle siding systems written about here are the same in that they both employ a drain plane to keep the wall dry The closed joint rain-screen looks no different from a traditional Seattle siding project but open joint rain-screens are strikingly different The open joints add shadow lines and depth that add real aesthetic interest In my next post on this subject I will discuss how the various systems on the building need to be integrated into an effective rain-screen Seattle siding system.
