rain screen style of construction

[bjbTay]

Aloha,

Could anyone tell me if rain screen construction is being done on the island? We are considering using Hardie Panel as our exterior siding, installed over James Hardie furring strips, with Tyvek UV Facade membrane, (which is designed specifically for open cladding construction). Rain screen style of design/construction is being used a lot on the mainland, from here in California, to Colorado and up in Washington, for it’s ability to prevent mold and water penetration from wind and rain, so it seems to me it would be ideal for Hawaii's weather. We also will be using light weight steel studs.

I appreciate any comments, thank you,
Barbara Taylor

[bjbTay]

I just investigated further and found that the Hardie Panel is not installed using the rain screen method, it can be butt joined but must be caulked. So I don’t know if this is a good way to go or not. Has anyone done this contemporary look, with butt joint and caulk in Hawaii, and has it held up? It is obviously the Hardie Artisan Matrix panel http://jameshardiecommercial.com/artisan...anel.shtml that I have been seeing around here (CA) that is installed using rain screen technology, and of course it is only available in CA, OR, and WA. Back to the drawing board for me I guess.

Barbara Taylor

Hawaii Dreaming

[Hotzcatz]

To stay within budget, find out which materials are sourced locally and use those in your construction. Using less materials is also another way to stay within budget. Single wall construction uses a more expensive exterior siding method but there is no interior siding so the savings are made there. Same with the floor, if the "sub-floor" IS the floor, there is substantial savings in not having to put in a finish floor.

Single wall construction also doesn't have the problems with mold inside the walls. Several of my last clients (I do drafting) have chosen single wall construction since their budgets were pretty tight and they have been very happy with the results. Personally, I don't like drywall, so I'm for any design which doesn't use it but I'll draw it in there if that's what the client wants, it's their house, after all.

I've never heard of "rain screen" construction so I don't really know the details, but generally around here there are three to four foot eaves around a house which not only keep the sides of the house dry but also keeps the sun off as well. It is too expensive to run an air conditioner, so a lot of design considerations are done for house cooling. You not only want to build a home within budget but one which you can afford to live in afterwards as well. The less you spend on construction the less you will have to either earn or pay back and then you will have more time to enjoy your house.

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"I like yard sales," he said. "All true survivalists like yard sales."
Kurt Wilson

[bjbTay]

(I have also posted this as a new subject "construction details" since rain screen construction is no longer an issue.)
Hotzcatz,

Thank you for your reply. I have read a lot of what you have written on this blog and have a feel for your honest straight forward mannerism...much appreciated!!!! I hope you don’t mind if I elaborate here and take advantage of your expertise and hopefully others as well.

Yes I have been looking at materials sourced locally, I do understand the importance of that. It appears the 4x8 Hardie Panel is available (blog source mentioned this) and the reveal for the edging that James Hardie recommends (manufacturer says that Honsador handles the Tamlyn brand, but I have not contacted them yet to make sure they actually handle these specific reveals.)

How are people installing Hardie Panel for siding and on soffits? Here is a PDF link from the James Hardie Commercial web site - In figure 2, H Joint, this shows the revel. Have you ever specified this, or anyone that you know of used this method of finishing the panels, or are they just caulking the seams?http://www.jameshardie.com/pdf/install/install_panel_west.pdf

Here is another type of revel application:
http://jameshardiecommercial.com/hardie-...anel.shtml

I am one of those who would rather have the drywall, a clean smooth white wall for displaying art. Also, not really thrilled about using subfloor as a finished floor, although I did mention it to my husband as an area to compromise if we have to (perhaps using the concrete 4x8 T&G subfloor that Rob Tucker has mentioned), although would prefer a finished plywood for softness under feet, but we are trying to keep down the use of wood because of termites.

I am planning on taking advantage of the trade winds (have been listening to others on this blog and paying attention to their experience). We will be using a lot of windows, cross ventilation, limiting the southern exposure, venting the attic and providing some type of venting from the interior at the peak through the roof (skylight or equivalent... still researching that).

Also planning on 24" on ctr. studs, trusses, and joists, would like to use the light gauge steel. I am looking for a source on steel trusses. What I have designed right now is a scissor truss with 4' overhang, a 5:12 roof, and 3:12 ceiling. But yesterday I was reading the 1991 UBC Appenix Chap.25 on “prescriptive (doesn’t that mean required?) hurricane-resistant construction” and this threw me for a little loop http://www.hawaii-county.com/permits/hurricane.html
... it states that roof overhangs shall not exceed 3' (glad to hear you have specified 4' thus it must have passed code). It also talks about the exterior sheer walls at 4' min. at each corner (my design is not consistent with that either), and the exterior sheer wall width shall be at least half of the exterior wall length...oh dear, too many windows for that...we’ll perhaps need an engineer to specify ways around this without compromising the buildings integrity, and without changing the design too much.... It also states that 24"oc trusses require studs and joists to line up, this was my intent all along, but I have seen homes recently built in Hawaii that have 24"oc trusses with 16"oc studs...and it too obviously passed code?

Have thought about the Protec sips, but not sure we can use them, since our roof span with 4' overhangs will be 36' (18' to peak).... Also more importantly I have a few different floor plans I have been working on and one would require a 28' ridge beam, and the other would require a 24' beam to accommodate the sip panel...that is why I have been leaning towards trusses instead. As I am not sure if a long ridge beam is realistic on a budget, especially if it is out of steel. I will however price out this option if it makes any sense. I like the fact that on the Protec sip wall panels we could use the Senergy surfacing material that was specifically designed for their exterior finish (a stucco look), if available in Hawaii of course, then all this stuff about Hardie Panel would be unnecessary.

Right now I have to keep our options open and look at everything that could possibly work, only then will we be able to determine where to cut (compromise) and where to spend.

I will be able to draw up most of our plans, floor plans, elevations, I am however not sure about all of the detailed structural specifications, that is where we will probably need some help. I am able to visualize most anything, and can be very logical when pointed in the right direction. As far as drawing things up, my back ground is in interior design, furniture design, fine art, architectural renderings, and graphic design. I jumped around a lot, as I like new challenges, although that is s-l-o-w-i-n-g down as this body and mind get more worn out.

If you are interested I can send you some links that explain rain screen construction, it is cool if you are into a more modern/contemporary look. When it comes to modern architecture rain screen is what allows for design details that previously could not have be used. However it is used for traditional house design as well, as a major component to achieving a dry but breathable house envelope. Hummmm... maybe it is not used in Hawaii because houses are not sealed up so tightly, since preventing loss of heat is not an issue - okay.... well that certainly makes sense.

Sorry to expound so much, I appreciate your thoughts!
Barbara Taylor

Hawaii Dreaming

[bjbTay]

Hotzcatz,

Just when I thought I was letting go of rain screen... You have got me thinking...

You said “single wall construction doesn’t have the problems with mold inside the walls.” So what about those of us who want to use drywall? And perhaps are even thinking of using additional insulation along with the reflective foil, in their non-air-conditioned house to keep it as comfortable as possible.

Yes there are insulations that “resist” mold, like Johns Manville MR Faced, which has the added benefit of being formaldehyde free. I read on the blog that Grabber Kona had paper-less drywall, but it maybe not formaldehyde free. Besides I don’t like the idea that insulation only resists mold...that doesn't sound good. The question still remains, with normal Tyvek the wall is sealed up tight when using drywall, thus preventing a breathable house envelope which then promotes mold growth. Perhaps rain screen technology should be introduced into Hawaii’s building practices as an appropriate way to avoid mold.

In a rain screen style of construction, a water barrier/house wrap is used that allows the air to penetrate but not the water. The house wrap, manufactured specifically for rain screen construction has to be used, and there are many on the market now. This water barrier/rain screen house wrap is installed over the studs or sheathing just like normal Tyvek would be. Next, cementitious furring strips are attached to the studs, (where termites are not a problem the furring strips can be pressure treated wood) this creates a small air gap for moisture to drain away and evaporate. Then the exterior siding is installed onto the furring strips. Some exterior installations call for the finished material to be installed with actual gaps between the panels (hence what I have been envisioning for our house), which allows for air to easily penetrate to dry the wall, and there would be a dip edge at the bottom.

That is the best brief explain I can muster up based on what I know about it. Rain screen construction is becoming mandatory in many areas that receive a lot of rain. It started in Europe, a few years ago in some areas of Canada it is now mandatory, and I think all new construction in Seattle has to be rain screen, but I am not positive on that.

Is this something to discuss and see if it might be a valuable solution to some of Hawaii’s mold problems? The only thing I don’t know about is how humidity comes into play within this air gap.

Barbara Taylor

Hawaii Dreaming

[Rob Tucker]

Mold is an organism that requires food, water and air. Most often the food part of the formula is wood. Stop using wood and you suddenly eliminate or massively reduce a raft of problems.

[bjbTay]

"Mold is an organism that requires food, water and air. Most often the food part of the formula is wood. Stop using wood and you suddenly eliminate or massively reduce a raft of problems." Rob Tucker

Thank you Rob, I appreciate your input.

So, if we use a paperless drywall, is that okay? Or will mold grow on gypsum?

Thanks again,
Barbara Taylor

Hawaii Dreaming

[Rob Tucker]

Fact is that mold will grow on glass here. Gypsum and plasters and cement products are very alkaline materials. Molds prefer acid Ph environments so there is a inhibitor factor. Paperless drywall is a reasonably better product but the quality of the gypsum is quite low. Drywall is prefab low quality plaster and either way you get wat you pay for. But choosing paperless drywall is a step in the right direction quality wise.

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