Cedar fence pickets as cladding?
big__o
| Posted in General Questions on
Hi
I want to install open joint siding on the house I’m building.
The goal is horizontal boards over 1×4 strips. With 1/8 gap between each board. The house needs to be able to dry aggressively when it gets wet.
I can buy western red cedar fence planks in 8 ft lengths for about the same price as lp smartside or hardie board.
2 questions – 1.is there any reason at all that cedar pickets would not be a good idea?
2. Would either smartside or hardie board be better in this application?
The boards will be painted, regardless of which option we decide on.
Climate is zone 3a
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Replies
Tell us about how you will keep the rain water out of your walls with such large gaps?
Will you rely on a single water restraint layer? How will the UV light that gets thru the gaps affect this layer?
Will you have a large air gap behind the board to aid in drying?
Can you deal with the fact that wasp and likely other insects will be living in your gaps?
If the cost is the same is the hardy plank it seems like a poor choice. I think you should be able to source ruff sawn green cedar for much less if that is the look you want and are willing the repaint every few years.
Most barns use vertical siding as you describe and hold up well.
Walta
I won't keep the rain water out of the walls. A little will get in but if Joe lstiburek is to be believed open joint systems generally work better than non open joint.
There will be a .75" air gap behind the siding.
I will have two layers of web behind the siding.
No direct sunlight can get to wrb through a 1/8 gap. and very little reflected sunlight
Can you expound on why it seems like a poor choice compared to hardie?
Thanks
Max,
Can you link to Joe's comments on open-cladding?
Research by RDH shows that rather than a little bulk water penetrating gapped-cladding and hitting the WRB, quite a lot does. To me that means the cladding becomes largely aesthetic, and the WRB takes on the role usually assumed by cladding - dealing with wetting and drying further into the wall, where the assembly is more vulnerable.
A vented rain-screen is a well established wall assembly where the cladding acts as a first layer of protection, allowing the WRB and cavity to deal with residual amounts of bulk water intrusion, and allow drying from both the exterior and interior. If you need more aggressive drying than it can provide, I'd suggest there may be something wrong with the wall assembly that needs addressing.
I have done this with horizontal cedar boards (1x3). With horizontal boards a lot less water makes it behind but still way more than regular siding. You have to be diligent with your WRB details and you must use a UV stable WRB (ie AirOutshield UV or RevealShield SA). Make sure the product you pick is also vapor permeable. Be careful as there are a lot of UV stable products for roofing that are vapor barriers.
If you don't mind a bit more maitanace down the road, you can also use tyvek pained with a water based (permeable) outdoor black paint. Do an adhesion test first to make sure it stick and won't peel.
Thanks for this info. I was going to do what Eric reinholt of 30x40 design studio did- tar paper. But two layers. Actually, that's what I'm doing regardless ,as the tar paper on my 33 yr old house looked almost brand new when we changed windows last year-and this was with t1-11 siding right against the tar paper.
Hi Max,
Years ago I was looking into an open joint cladding system. They are awesome from an aesthetics perspective. I personally am not opposed to them in theory, as long as they're done correctly, however I've never done one and don't have personal experience so anything I say should be taken with a grain of salt.
I'm sure you know this, but for the sake of progression of thought: typically, cladding is meant to shed the bulk water, and then the wrb is meant to handle the small amounts of water that may or may not get through. It's a pretty good system, it has two layers of control to account for failures. (I live up north and like to do exterior rockwool between the wrb and cladding, which adds another layer of water management).
However, Doing an open joint cladding system is mostly for the aesthetic purposes. Where the assembly underneath, in good practice should still have a 2 layer system for bulk water+UV and small water management. They make special WRB's specifically for open joint systems that are black and UV resistant to protect the backside. They're much pricier than your hardware store tyvek. I'd suggest that underneath your boards if you're going to do an open joint system.
As to your questions:
1. Cedar boards can work, they're dimensionally more stable than Hardie, but they'll certainly require maintenance to keep them up to snuff. Just like any ol' fence they're susceptible to greying and checking. I just had a neighbours fence board fly off their fence from a wind storm and smash a skylight at my build.
2. Hardie to my knowledge in talking to their technical team, is not designed to have bulk water on their backside. Their waterproof layer is the paint. You might get early failures with them. I've done a bunch of personal tearing with hardie with water and freeze/thaw stuff. Smart side I don't have experience with but was looking at their website yesterday. I don't think they have straight planks? their system is for lap siding which I think would look horrible if you gap them. And to which I'm sure the OSBness of them will fail earlier than wanted with bulkwater getting on the backside. Something you can c and ask their technical team about.
Just some thoughts,
Jamie
Thank you for chiming in. Actually I only desire the open joint so the house can dry. I like lap siding just fine and some of the comments here have me really re thinking this open joint thing.
Lap siding can look goooood
https://images.adsttc.com/media/images/517e/dbd7/b3fc/4b0c/e700/0036/medium_jpg/8569_021_copy-2.jpg?1367268307
I found Joe's open-cladding comments. There are a couple of things that I think are problematic in them.
The first is his dismissal of the amount of water that penetrated the wall. RDH shows it isn't insignificant, whether or not the open-cladding dries at a rate higher than it allows wetting, you are still allowing too much wetting to occur. https://www.rdh.com/wp-content/uploads/2017/10/RDH-BSL-Drainage-Balance-Spray-Rack-Report.pdf
The second is being really vague about what happens behind. He says the WRB needs to be aesthetically pleasing if it will be visible, and last a long time. But that avoids the questions around detailing it at openings, or even fasteners, if it is being asked to now stop bulk water intrusion. That's independent of how well the cavity can dry. How do you effectively detail the WRB to stop water getting further into the wall?
It's all possible, and probably would work fine, but the only reason I can see to go that route is you want open-cladding for aesthetic reasons. If the performance of the wall is the primary concern I'd choose another more appropriate assembly recommended by this link:
https://www.rdh.com/wp-content/uploads/2017/07/Guide-for-Designing-Energy-Efficient-Building-Enclosures-Web.pdf
This is VERY helpful information.i thank you. From the first link, it looks like the open joi t cladding with half inch gaps admitted quite a bit of water.
From the second link, it says wood dries by vapor movement from wet area to dry area. So with cedar maybe I don't even need a rain gap? Very interesting. This has me leaning more towards lap siding now. I like the look of lap siding and it would save a step if didn't have to install firring strips
first
THANKS!
Max,
For almost any climate, and wall assembly, the benefits of a rain-screen are worth the additional work.
The fact is Hardy plank has won the marking war and the public sees it as a premium product that adds resale value to a home compared to oddly repurpose fence boards.
I am not saying do not do it just that the low maintenance and resale value makes the Hardy a better choice if the costs are equal.
You could rip the edges of your boards at 22.5 ° or 45° so that water would have to move up hill to enter your wall.
If you are committed to this look, I bet you can find a local mill to supply the green wood that install tight will dry and leave the gap you want for a lot less money.
Walta
I can understand it.lower maintenance wins. Almost always.
I wanted open joint just for the supposed drying capability. Now I'm thinking of regular lap siding. I will research the breathability of hardie board.
Oh I'll also look for a supplier of green cedar. Thanks for the suggestion
Thanks.