Opinions on Keene Easy-Fur Strips for Rainscreen
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Anyone have any experience using 1/4 in Keene Easy Fur strips as a rainscreen behind hardie board siding? Seems super easy to use… tack up on the top of the wall on a stud… unroll, cut, done. I am worried that it has some compression properties that might cause hardie to crack when shot with a nail… I also like the 1/4 in depth… i think it will make trim work easier…I am not required to do a rainscreen, but want one for the benefits.
Steve
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Replies
Hi Steve,
I haven't worked with the product, but it looks pretty straightforward as its a spun poly strip. Any gap behind the siding is going to help mitigate driving forces that can bring moisture into the assembly by reducing hydrostatic pressure and allowing for drying. This should also help mitigate paint degradation issues such as solar vapor drive.
I would venture to guess this won't affect the hardi or create a wavy install. I would be sure to use it horizontally at the bottom of your wall, at tops and bottoms of windows and punched openings and also at the top of the wall to keep critters out.
Another similar option, and potentially more cost effective would be to consider using simple sill seal. You would still need an insect screen at horizontal locations. With either of these options the benefits are decent, it is cost effective and won't adversely affect the window and door trim outs.
Josh,
I wouldn't recommend sill seal to create a rain screen cavity. It's too thin and too compressible. If it's just being used to upgrade a wall that wasn't going to have any rainscreen at all, it's probably better than nothing. But it won't give the full performance of a real 1/4"-3/8" gap. Plus, it'll have more risk of being wavy because of its compressibility. Most of the sill seal I've worked with also has questionable longevity. Just not a very high-end product for something that's going to be built into the walls forever.
The Easy-Fur strips (and similar tangled-web products) are surprisingly stiff and very durable. Not sure about how cost effective, but easy to use and will do the job.
Copy all, yup I was planning on installing it vertical and then horizontal at the top and bottom to keep bugs out. My biggest concern was causing waves in the siding, like you mentioned, due to the compressibility...but since it’s only 1/4 thick I can’t imaging it can be compressed more than an 1/8 of an inch. Still debating hardie or lp smart side.
Willy,
Rain-screens give you an number of benefits:
- A capillary-break
- A gap to help redistribute moisture, both from the siding, and that passing through the wall from the interior.
- A drainage path for any water that makes it's way into the cavity.
- Some ventilation for drying.
As you reduce the depth of the cavity you begin to lose some of these attributes. The WRB is more likely to block the cavity, bridging the capillary-break and reducing ventilation, and the gap may not introduce en0ugh air to dry the materials.
How important that is depends on your climate, and what y0u are asking the walls to do. For instance, in exposed locations with no overhangs the wall is expected to handle more moisture that it might otherwise do.
To me the Keene strips, at just over 3/8" (10mm), are just on the right side of what I'd consider a useful rain-screen. I don't see much p0int in using a material any thinner where the depth of the gap eliminates so many of the beneficial features of the assembly.
Thanks,
The house is going to be in zone 6...Maine... and I’m planning on using zip for the WRB so that should stay pretty consistent to not diminish the small rainscreen gap.
Willy,
If you are planning to butt your corner and window trim to the siding, rather than put it on top, you may want to have some plywood strips of the same thickness on hand so you can place them under the intersection of the two.
Hi Willy. I work for Advanved Building Products which is located in Sanford, Maine. Not sure how far that is from you but I would love to talk to you about some product choices you have. We specialize in manufacturing drainage and ventilation materials for projects just like yours. You have two options. You can use an All-Wall drainage mat such as Mortairvent. It’s a product that goes over your WRB and covers your entire wall and creates that capillary break that you are very wise to be looking for. The next option is a furring strips like you mentioned. Our furring strip is called WaterairVent. There are two reasons why I like it more than Keenes Easy Fur. For one thing, Keenes product won’t give as strong of a bite as our furring strip will. Meaning, the furring strips should not only create a capillary break for drainage and air flow, but you want it to offer a bite for your nail to help hold the siding up. Our product offers that. WaterairVent is a very strong composite furring strip that has drainage channels to allow airflow and drainage even behind the furring strip itself, so like you would with Easy Fur, our product doesn’t trap any moisture. WaterairVent can be used vertically or horizontally. But, the clear advantage is the fact that our product offers a more substantial surface to nail to than an entangled net product like Keenes easy fur. Google WaterairVent and take a look and feel free to call me with any questions. I can get a sample right out to you and we can get you whatever product you need, made right there is Maine. My info is below.
Dan Frattinger
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(630)540-6732