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Housewrap vs Drainage Wrap?

Posted by mark_g (My Page) on
Wed, Nov 5, 08 at 13:56

Appreciate comments on what housewrap you used or are considering.

We're building in NY State. House is framed and we're planning foam or cellulose insulation in 2x6 walls, fiber cement siding (Nichiha or Hardi).

One new development that caught my attention are drainage barriers--a textured more 3D material that is supposed to channel any moisture that migrates past the siding down and out, in addition to offering vapor midgration similar to Tyvec. I have a sample of a product called Vortec -- has anyone used it? I believe Dupont has a similar material. Any experience with this material affecting warranties on cement siding?

Thanks for feedback! --Mark

Follow-Up Postings:

RE: Housewrap vs Drainage Wrap?

Hi Mark,

We looked into the drainage wraps and ultimately passed as the most common brand we found in our area is Homeslicker, made by Benajamin Obadyke (sp?), and it has a small compression value, and we didn't want to have any concerns over wavy fiber cement. We chose, instead, to use vertical furring strips to achieve the same drainage plane result. We also used a product called coravent located at key openings (windows, skirt board, etc) which is designed to allow air flow, while also preventing insect entry.

I would suggest doing a search here for Rollie's Delores house which provides an excellent reference for this sort of exterior design. Keep in mind that it is especially important to ensure your flashing details are sound when using this method..... it can get a tad tricky.

We're using Nichiha siding and I know their reps are perfectly comfortable with this installation (ie no warranty issues).

Good luck!

RE: Housewrap vs Drainage Wrap?

House Wraps like Vortec that don't want to tell you how it is made, are probably micro-perforated polyethylene which, in my opinion, is not sufficiently water resistant to be used in a wall assembly as a weather barrier. I would recommend spunbonded wraps like Tyvek and Typar. You might consider using Tyvek Drain Wrap or Stucco Wrap (same thing) if you think the amount of rain in your area justifies it.

RE: Housewrap vs Drainage Wrap?

Vortec is high-density polyethylene. (See technical specifications at the website below.) Under wood siding, I've used Tyvek followed by wood furring and appropriate flashing.

Here is a link that might be useful: Vortec

RE: Housewrap vs Drainage Wrap?

Thanks for the feedback--appreciate clarification. If Vortec is HD Poly (as opposed to regular poly), is that satisfactory for water resistance? I like that the pattern is non-directional, compared to Tyvec, which has to be installed only one direction. --Mark

RE: Housewrap vs Drainage Wrap?

According to the manufacturer, the product is laminated and micro-perforated, as opposed to spunbonded polyethylene and polypropylene.

It has a lower permeability than either Tyvek or Typar.

But you also might want to look at comparisons for tearability, surfectant resistance and a host of other things. The fact that it is said to drain in all directions is not that important to me.

RE: Housewrap vs Drainage Wrap?

In our mixed-humid climate, we've used Typar with Homeslicker rain screen, and Nichiha shakes/siding. Nichiha is slightly thicker than Hardie, but I can't comment on the warping issue.

RE: Housewrap vs Drainage Wrap?

Here's the website that Niff suggested...

Here is a link that might be useful: Delores House

RE: Housewrap vs Drainage Wrap?

Most house wraps are made of polyethylene or polypropylene. Some are cross-woven with a micro-perforated coating, some are porous film laminated to scrim, some are non-woven spun-bonded, and there are other variations. The micro-perforated ones are the least water-resistant. I recommend using the non-woven ones like Tyvek, Typar and WeatherSmart (Fortifiber) and would only use one of the others after testing it for water-resistance.

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