You could always just keep the rainscreens to the most vulnerable areas like gable ends or walls not well protected by overhangs.

I think pre-finishing should alleviate some concern and tyvek drainwrap is certainly better than plain old tyvek. Still for real wood siding, I wouldnt feel good about the install unless it had a bigger air gap (3/8-3/4"). Drainwrap/stuccowrap might get you 1/32-1/16". Does anyone know if "drainwrap" is the same as "stucco wrap"? I think they just re-label it but not sure.

Not sure why you didnt look into plywood strips/1x strapping and coravent but it sounds like your builder may not be up to the challenge. Where did the coroplast comment come from?

Hi, Brian. Thanks as always for chiming in! Another contributor suggested getting sheets of Coroplast (corrugated plastic signboard) and ripping it into battens. Apparently this was done by enterprising folk before Dupont decided to make and brand rain battens. It's cheap as chips from a materials perspective, but I think our builder is sick of the whole conversation and sort of implied a high labor charge when we suggested it. We didn't consider the plywood strip option too much as they would need to be horizontal for the vertical siding which sounded like it might create its own problem.
Right now I'm leaning toward going with the Homeslicker (just seems like the most mistake-proof option), downgrading my counters, and tiling the bathrooms myself.

In your expert opinion, is the air gap structurally important enough to make these concessions? My builder seems to think that rainscreens are Kool-Aid and we're stupid to be drinking it.

This post was edited by Kiwigem on Fri, Oct 3, 14 at 22:26

Your builder is uneducated and inexperienced in the ways of rotting siding. You are more smart than him in this area. Guess you didnt see my blog on the subject, and it depends on the situation but you dont necessarily have to use horizontal battens for vertical installations.

Thanks for reminding me about the coroplast. The coravent product uses the same material but has added an insect screen though I wonder if its really necessary and might consider using the cheaper version in the future. By the time you rip and stack the coroplast, it might be up there with the coravent. Either way, I only think that material is necessary at the top and bottom of the siding and would go with wood for the battens.

Its a really tough call in your situation as to the worthiness of these exercises. As owners, designers and builders see the light and are enforced to use these practices, this will become less of an issue. If you werent using real wood, I would say settle for a drainable housewrap. Since you are using painted cedar though, I think it makes sense to get a legitimate air gap between the sheathing and the siding. It should dramatically increase the time needed to repaint and could add 100 years of life to the siding itself.

I think we will go with the homeslicker and try to recoup the cost in finishes. As my dad said, build the best house you can, not the prettiest house you can. Plus, something you said above makes me wonder if drainage planes are going to be required before too long. I wouldn't want a future code change to have the building methods used on our house to be considered the "old way" to a future buyer.
Thanks!

As I mentioned earlier, not only is the thin horizontal drainage strapping described here needed for a rain screen system behind vertical cedar board siding, it should be installed over horizontal interior wall blocking so that the siding nails can penetrate through the sheathing and at least 1 1/4" into solid wood (studs) in order to prevent cupping. You will find a similar requirement in any vertical siding installation specification or guide.

In 1977, the boyfriend of the owner of the first house I designed decided to install vertical instead of horizontal siding over CDX plywood himself and in spite of my warnings he nailed it to the sheathing and it all cupped so badly that it had to be replaced.

Perhaps switching to horizontal siding might save enough to pay for a rain screen system. The choice does not have to be between the best house and the prettiest house.

This post was edited by Renovator8 on Tue, Oct 7, 14 at 11:01

Reno8 I see you are editing your original response and I'm looking forward to seeing your edits as I have really come to value your opinion. Regarding rainfall, I don't know what is considered heavy. I know we were ranked one behind Seattle for number of rain days, but not sure about actual rainfall amount. Lots of high humidity, but not sure if that is relevant.

Edit: Just read closer and answered my own question. Thanks for you input, Reno8! Very helpful as always.

This post was edited by Kiwigem on Tue, Oct 7, 14 at 14:06

Kiwigem - is your cedar going to be open-joint? Sounds similar to our project, we have a rain screen as well with the open joint cedar. I wanted to go with vertical cedar, but ended up with horizontal as it was more cost effective in the end. Sounds like a great project, good luck.

The solid wood siding I've installed must be installed with strapping. (See Installation directions in link.)

The details are straightforward and reflect the directions and warnings stressed by the other posters above.

didn't consider the plywood strip option too much as they would need to be horizontal for the vertical siding which sounded like it might create its own problem.

That's why the instructions linked below call for 1/2" drainage slots every 48" in horizontal strapping.

Here is a link that might be useful: Cape Cod Siding Installation

Our cedar siding is installed with strapping as well, fwiw.

That's hugely helpful, guys, thanks! I actually just noticed that Hardie (our accent areas are Hardie panel) does not recommend a drainage mat for a capillary break- so the horizontal strapping sounds like the way to go after all. I wasn't aware of the drainage slot practice, worthy- thank you so much. Virtual cyber fruit baskets for all of you!

Hi just wanted to chime in quick, I recently designed an addition to a historical house in the downtown district of my city and city planners required rain screen to get the building permit. so it likely be required elsewhere I'm sure

sochi, I love your open joint siding. Ours is spec'd as varied- width vertical shiplap. All the more reason to have the air gap, right? Our house has some strong vertical lines, the way yours has strong horizontal lines, so the vertical siding really suits our design the way the horizontal suits yours; I'm glad you didn't choose vertical for yours! We already have Tyvek up so I think we would need to re-wrap the house in a reveal-type paper if we were to do an open joint. That's another discussion to show how little I know, though!

CivilTech, that is something that has occurred to me; the notion that an air gap will likely be code in our area someday. I'd hate to build this house only to have the skin of it be thought of as obsolete in 10 years! It's inevitable eventually I guess, no matter what you do.

My folks house has original vertical cedar 1x6 from the 70s, as many of the homes in the neighborhood do, and its installed vertically with no strapping right up against the felt and plywood, obviously not into studs. No cupping but the paint finish and ultimately life of the wood would probably be longer with a gap. Type of fasteners, whether the back is primed, and existence of a rainscreen gap would all effect material movement.

Unless you are building in high wind zones, including foam sheathing, a rainscreen and types of fasteners are probably more important details than penetration depth or hitting every single stud or block.

If you want the drainage gaps, simply take T111 siding and rip it into strips cross grain and install upside down. You'll have a drainage slot every 8 inches.

Rollie, you're the man!

Maybe it is just me but a "drainage plane" using plywood (or any wood for that matter), seems to me to be a bad idea/ Water running thru plywood channels and against wood in general is a disaster waiting to happen. Wouldn't you siding rot from the inside.

This rain screen wall cladding design is really just a drainage cavity similar to the one in a brick veneer cavity wall system. Most of the water that penetrates the cladding or condenses on it would be expected to drain down the back side of the cladding to the weeps at the bottom of the wall, at the heads of window and door openings and at any other horizontal breaks in the siding.

The placement of partially grooved horizontal strapping in the cavity could force some water against the Tyvek side of the cavity and that should be avoided in a drainage cavity if possible.
Horizontal battens present a challenge to the design of a drainage cavity. If they cannot be avoided they should be as continuously open as possible and at least 3/8" thick because the capillary action of water can prevent it from passing easily through small cavities. Therefore materials with straight vertical internal fins are preferred to corrugated ones. As for materials, I would not expose the edges of plywood, OSB or anything that might swell, delaminate or deteriorate from repeated exposure to moisture in the cavity.

I don't know anything about the house design but I would seriously consider placing the cedar boards horizontally and allow the drainage cavity to function to its full potential without back priming.

Here is a house I built in 1983 with 3/4" horizontal strapping. ()taken July 2014 This was in the infancy stages of vented rain screen design. The cladding is in perfect shape, even after 31 years.

There were no allowances for water to drain to the bottom. Just a disconnection of the cladding from the structure. The only allowances we made for this assembly to breathe, was ventilating the air spaces to the corner, and then vertically up to the soffit. There is 30 lb felt under the strapping.

Even with the worst installation, a minimum amount of water actually gets into any assembly. The problem is in a conventionally applied assembly and when it soaks the materials, and cannot get into a vapor form..

Any air space/gap is a good thing.

Even the worst designed vented rainscreens like this one, perform far and above conventional installations.

Its not really rocket science, unless you want it to be.

I totally agree. Its the airspace that matters. Beautiful work rollie.

Even the tiny spaces of drainable housewraps seem to make a big difference in how water drains behind cladding materials. As for the swelling of plywood batten edges, I can imagine horizontal applications being more risky but it seems to be the material of choice for vertical application of less than 3/4" thicknesses for reasons of regular wood splitting and cost of specialty products. If your battens are getting soaked enough to matter, you probably have more important flashing improvements to take care of.

Brick and masonry airspaces tend to be different environments with higher moisture risk but you shouldnt need any battens in there.

Here is a link that might be useful: GBA: All about Rainscreens

This post was edited by Brian_Knight on Sun, Oct 12, 14 at 15:37

Thanks, Brian. Im glad to see that someone "gets" that its not that technical.

Martin and I go back to the old,old EEBA days..

If youre worried about water standing on the horizontal battens, why not run the battens at a 15 degree pitch to the outside corner? You could get real tricky and rip a V into the top edge of the batten, so the water had a channel to run in. :)

Wow I've missed some activity on this thread! Thank you all so much for all your incredibly valuable help. In the end, I realized that I was definitely over thinking the whole system (better to over think it than under think it, though, right?) and we will be installing standard horizontal strapping with gaps between the straps. The air gap created will be better than most houses built in our area and since we are in a moderate rainfall area I do believe it will be adequate. Rollie, your photo gives me great confidence- it looks beautiful. Great work and thank you for sharing!

Looks like you made the right decision. Small airspaces appear to be almost worthless.

Is Your Rainscreen Deceiving You?
http://builtenv.wordpress.com/2012/02/16/rainscreen/

Here is a link that might be useful: rainscreen

That's a great link- thank you. We aren't doing stucco, but it's good food for thought for the masonry areas of our house.

This post was edited by Kiwigem on Mon, Oct 13, 14 at 18:26

I understand the linked information, but Id like to know how they achieve 100 ach on the .75.

What would a .25 look like with 50 or 100 ach?

While that link is interesting, here's my main problem with it: "hygrothermal simulations to predict..". Now Iam not disputing anything they have modeled or concluded but they seem to be dismissing the fact very small air-spaces and gaps dramatically change the way water drains behind cladding. Also, stucco seems to be their main concern in that modeling exercise and rightfully so, its a tough product to get right in rainy climates when installed against wood framed walls.

Here is a link that might be useful: hyrdro gap simulation

That's a good point, Brian, regarding the stucco aspect. From a common sense perspective, it seems obvious that even a small gap will help water get out; it is, after all, small gaps which let the water in. It has to be better than a flat "sandwich," even if it isn't the perfect world scenario.

Try this experiment with regular housewrap.

Here is a link that might be useful: Matt Risinger's drainwrap test

Risinger's videos are such a great resource for no-nothings like me. Thank you for the link; I hadn't seen that one. Very elucidating!

Guys, if any of you see this, would you kindly look at my recent thread about the Hardie Panel and air gaps? After all the back and forth I just found out that the architects didn't draw the air gap for the Hardie. And siding is supposed to start IMMINENTLY.
Thanks.