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The Ideal "Puna" House Design
#1
So, certain house designs generate a real following. One would hope that technical merit would figure prominently in the design process but other things sometimes take over. I suspect this is true for earthships. They have a lot of features that are excellent for deserts with wide temperature fluctuations and where there is dirt in abundance for construction. Same with adobe, strawbale, and cob. I think these construction techniques are unsuited for our wet rocky environment.

Why do I mention them all? Because I have seen others mention them and I have considered them myself, and it is clear that the attraction does not always stem from how technically well suited they are for this environment, but rather from the association they have with alternative (and therefor better?) construction techniques. I myself was considering converting a steel arch building into something habitable until I realized that I was just trying to be different and was going to wind up paying handsomely for the privilege, while getting a house every potential buyer would think was weird.

So what are the unique environmental characteristics of Puna that would determine the design? First, rain. I think that massive roof overhangs would be a must. A wrap-around lanai would be good. I see lots of mainland-style house designs that have very minimal overhangs and rely on good shingle or siding systems to keep water from penetrating the walls. 200 years ago there were only slate, wood, or terra cotta shingles. Hundreds and hundreds for each roof. It probably made no difference in terms of labor or materials whether you put them on the roof or the walls. Today you can buy 20' x 3' sheets of corrugated roofing. I say put a big roof on and never let the rain get to the walls. Then reap the benefit of the large overhangs to keep the sun out while allowing good views. This would be a variation of a rain screen or rain shadow type of design.

How to deal with temperature? That is not going to be much of a problem in Hawaii unless you are in Volcano maybe, and even then is is nothing compared to the high desert of our western states. I think thermal mass is always good, plus a little insulation in the roof.

Rot. Avoid wood if possible. Keep whatever wood is used as far away from the ground as possible. Keep the roof design as simple as possible to avoid leaks.

Termites. Same as for rot. Termites like water so moist wood is at risk from both rot and termites.

Mosquitoes. Not a huge problem in Hawaii, but if you are designing from the ground up, what features would be good? In some parts of the world houses are built on stilts. Apparently mosquitoes tend to hang within 10 feet of the ground or so. If the design permits it, keep living spaces as high as possible.

Ventilation. Again, build high to catch the breezes. Many typical Hawaii houses already incorporate this feature. Also, temperature fluctuations tend to be less the higher you go.

So, a good design seems like it would be a two-story design with a large wrap-around lanai, possibly screened in, made of concrete or some concrete based product. Concrete doesn't rot, is not palatable to termites, and adds thermal mass. A hip roof and the lanai would protect the walls from rain. The lanai would add much living space that would be infinitely well ventilated.
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#2
Good starting point.... mosquitoes are a pain here for some (ps. mosquitoes here REALLY like plumbing drains.... nothing better than to start a shower & have a cloud of 'em rising up from the drain!), and VOG & ventilation can be a real drag on those with respiratory problems.

Earthquake: keep the roof light. The higher the building, the more movement; plumbing, electrical & all furnishings must be able to account for the sway movement (a broken plumbing line in a wall after a 6.0 is a real hassle).

Because of the uniqueness of each area of a subdivision, let alone all of Puna, it is best to design for the area, even the lot, that you are building for (how 'bout that for a statement of the oblique?).

We have have yet to figure out how not to have any wood, that, along with the problems steel, and most metals, has with moisture, VOG & salt spray (even a couple of miles from the ocean, our Makai side "lifetime finish" SS door knobs show salt damage!) makes any design open to some building material generated weakness. (Have seen fairly young structures that have had Simpson tie corrosion... not good!)

Forgot to add: the corrosive effects some of the visiting critters can appear on some, if not most, building materials



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#3
Good points. I forgot to mention earthquakes. They are one reason that I think really massive but low tech structures like earthships would be ill-suited to Hawaii. Not to say you can't use piled rocks but there has to be sufficient reinforcement and allowance for seismic movement. Good point about the roof. I saw some pictures from Japan of wooden buildings that fell down because they had been retrofit with heavy roof tiles.

I think thermal mass is always good but we just don't have the daily temperature swings here in Hawaii to warrant going overboard with massive stone structures if it puts you at risk from earthquakes. Too bad. Natural stone structures can be really nice but the point of this exercise is to separate what's nice from what is really appropriate technology. I catch myself thinking "Gee. Strawbale sounds neat", but there's no straw within 2,500 miles!

Personally, if I ever get my act together and build something, it will incorporate some kind of wood burning heat source. Too many people get confused about this being Hawaii and think you don't need heat. I don't care if it is only 10 days out of the year, when I am cold I want heat. I have a totally irrational infatuation with Rumford fireplaces, even though open fireplace = awful efficiency. However, here in Hawaii the outside air a fireplace would suck in is at least above freezing, and there are ways of maximizing the efficiency of a fire if you tend it constantly. If it were to work anywhere, Hawaii would be the place.
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#4
Mark,
At my age, I also have to give serious thought to future accessibility for individuals with limited mobility. I want my wife and I to be able to live in our retirement house as long as possible, even though it is not a problem now. That is why I do not want a 2-story house or a house raised very far above ground level.

Allen
Baton Rouge, LA & HPP
Allen
Finally in HPP
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#5
I think I would qualify to respond to this thread because I designed and built a home there 3 years ago, and now, after living in it for nearly 3 years, I have already designed the next house we will be building there. I will start from the bottom and work up with the differences.

first house: post and pier, 4 ft. up
next house: thickened edge reinforced slab...(our age issues with stairs and more conducive to the smaller lot we own).

first house: conventional framing, insulation, double wall, hurricance ties, T 1-ll siding.
next house: the same because of earthquakes..wood gives. I believe with upkeep, T 1-11 is about as good as any other material.

first house: windows per mainland standard, vinyl
next house: more and bigger, vinyl and sliding or french doors
( will make it fill more like you are part of the outside...but able to close off for weather, privacy, bugs and coquis)

first house: 2 bed, 1 bath
next house: 3 bed, 2 bath (people do come visit!)

first house: gable roof, metal
next house: pyramide hip roof, metal

first house: lanai on back
next house: lanai wraps two sides (you really do live out there on
them)

And mold retardant paint always!



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#6
Accessibility was one of our thoughts, too. This may not seem like a biggie, but many of the people we met in our first year here were coming to terms with the fact that the dream house they built a decade, or so, ago would have to be sold for the fact that they could no longer manage the stairs, upkeep, etc. These are people that had built their dream at about the same age that we were going into the process, and now were having to part with the dream.... one thing we took away from watching this, it is not an easy decision to leave your dream.

We changed our "dream" drastically to more practical terms...

Oh, and rats! be aware that they are here & can do many amazing & almost undetectable things to your house structure... Termites, salt, VOG, moisture, cockroaches (they are just creepy... don't really effect the building) & rats have changed our views on all building materials, and structure plans.

Also really know your lot. Our lot has blue sky much of the time from the makai & Hilo side (east & north), and clouds much of the time from the mauka & Puna side (however, when clear, the mauka view of Mauna Kea is wonderful). Our lanais & windows almost all are mauka & Puna views (west & south - normal in building), We added a few to gain the sunny side of the lot... but the structure of the house was not set up for the average sunny side time... but has great views on those rare clear mauka days.... We bought an older house during a clear month....
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#7
Yep exactly Carrie. So many people build up high on posts and that just won't work when we all reach the "golden" age or what ever.
Also, I kinda like to walk out of my house into my yard and gardens...I don't get that same feel from high up going down stairs. Do you think people built high up to deal with issues of maintanence that can be dealt with other ways?
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#8
I have seen many houses in Hawaii that were built high up with a space underneath. Does anyone know why? I have seen it done where it was the easiest way to deal with the slope of the ground, so one side winds up being quite high off the ground while the other side is only a couple of feet, but I have also seen houses that were much higher than necessary to deal with the slope.
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#9
I have heard many people talk about the extra storage they have with the raised house....

Be aware: in the Oct. '06 earthquake much of the damage to structures was when an unreinforced monolith structure moved, and when a P&P structre moved off of the piers.... I studied a report of a homeowner that lost his house & his company, as he stored all of work equipment & vehicles in the space under the house... I have yet to find any earthquake insurance coverage here, so all of the damage in an earthquake is not covered... unless you can get coverage. The homeowner mentioned in the report did not have coverage for damage to his vehicles, due to the fact that the damage was caused by the house & not covered in his homeowners insurance....

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#10
We did several things to the Argus Kit House we built that were to improve air circulation and openness. It's a 3 bedroom 2 bath home designed for 8' walls and conventional flat ceiling trusses with a big open area for the kitchen/dining room/living room. We increased the wall height to 10' and put scissor trusses over the main living area. What a difference between our home and the regular built one we toured. Ours is much more open and airy. We also put in 5' tall double hung window. With that we got extra light and air circulation.Everything else is pretty much as designed originally. These improvements did not increase slab or roof costs. Mainly it was longer studs and some extra T-111. Didn't even increase framing time much. All in all we're quite pleased with it.
Home of the "Just for Keiki" Luau show.
See: http://justforkeiki.blogspot.com/
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