Replies

1. 
   Guest_ | Sep 29, 1999 05:46pm | #1

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   Doug-

   There was a study done that was published in either FHB or JLC (I'm pretty sure it was in FHB - a search on the homepage should find it) that compared different housewraps and 15# felt. The study was to determine whether certain extractives that bleed out of certain woods like redwood and cedar affect the water resistance of housewraps. Without digging out my back issue, I can't give you specifics, but I remember that out of about eight housewraps, the only two that had reasonable resistance to water when exposed to these extractives were Tyvek and the 15# felt.

   Others on this site will have other information to add, but try a search on FHB's web page.

1. 
   Guest_ | Sep 29, 1999 06:45pm | #2

   *Doug - you might want to consider using a rain screen between the wrap and the siding. Not only will the allieviate the problem you ask about, it will help your siding breath and last longer. It will add a small percentage to the final price of your home, and with the cost of Cedar what it is, could be a sound investment. - jb

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   Guest_ | Oct 03, 1999 08:27pm | #3

   *Jimbo is that rain screen the same material that is called breather material? Looks like stiff black string in a freeform overlay pattern?

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   Guest_ | Oct 05, 1999 04:21am | #4

   *The Cedar Breather (one brand name) stuff is a rain screen, but so is just a series of lath strips applied between the felt/tyvek and the siding. Anything that gets air back there. Mongo has mentioned a few times that something should be jammed up under the bottom course of lap siding if the lath approach is chosen, so critters can't crawl up. I think he suggested something like rolled up window screen. The lath approach is a lot cheaper than Cedar Breather.

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   Guest_ | Oct 05, 1999 08:03am | #5

   *I've used both tubes of window screen and strips of ridge vent made by Cobra. Black, comes in rolls, looks like a brillo pad. Gone overboard...on a recent job used cobra wrapped in window screen! The buyer was a hands-on guy and was fretting over each, I finally said "how bout both?" You should have seen his smile. After the first clap or two are on, I also sprinkle a just a bit of boric acid behind the claps and on top of the cobra.I consider the cost of a rain screen to be negligible. Lathe is inexpensive, the cobra and screen are inexpensive. Built up corner boards and jamb extensions on the interior do add a few dollars, though.Offset those costs with a better envelope, better water protection, longer siding life, longer paint life, and no thermal/condensate telegraphing the stud locations on cool mornings. I think its a worthy detail.While the siding should always be backprimed, if you choose to pass on the rain screen and lay the siding directly on the housewrap, you can minimize, maybe even eliminiate the surfactant/housewrap problem by backpriming/sealing the siding.

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   Doug_Atterbury | Oct 05, 1999 08:08am | #6

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   I have been reading some discussions here of how cedar siding can break down Tyvek housewrap. Is this acknowledged by the manufacturer?

   Does the same thing happen with other housewraps, like Barricade, which my builder plans to use?