Lightweight concrete. ACC blocks. Anyone have experience with these? (Hilo: loft, houses)

[Doctor Atomo]

I am moving to Mark Twain within the next year. I will need to build my own cabin to start and am looking for the most efficient building system.

Right now I am thinking of building a concrete block wall on a pad or perimeter foundation for the first floor with shop/ laundry/ bath, a living floor with kitchen, lanai, maybe one bedroom, and loft for sleeping.

I am thinking concrete for the first floor for termite resistance as well as wind resistance. Thinking in case of hurricane we could retire to the first floor.

I am planning on significant openings in the block walls for ventilation, and installing roll up doors as I can afford them for security and in inclement weather.

My question is: Has anyone used lightweight concrete, such as Autoclaved Aerated Concrete?

Aerated Autoclaved Cconcrete Structures

or

(Island Ready Mix Concrete - Kapolei, HI) Island Ready-Mix Concrete: Building Affordable Concrete Homes

I am wondering about the costs benefits of these systems over regular concrete blocks.

It seems these systems have a much improved insulative factor and the large light weight blocks wouldgo into place quickly! The importer of the first system says the blocks can be delivered to my site for $6.25-$7.95 depending on whether I want the steel reinforced or not.

He also says that the building dept. has no problem permitting a structure built with them.

ACC blocks however need to be finished, where regular concrete blocks do not, as the ACC blocks can absorb moisture.

Insulation is of little consequence as the temperature is very moderate at my site. Also as it will be an open shop the humidity will be ambient.

I plan on the second floor and loft being wood, unless the ACC is cheaper! A good size lanai and overhanging steel roof for outside living will finish the structure.

Water and and plumbing will be confined to a single wall with the kitchen and bath, septic will be septic tank/ leachfield or cesspool, whichever is permit-able in my location.

The land was bulldozed some years ago and there are no large trees to move, the building pad/site has been constructed and a plan was ok-ed by the building dept some years ago.

There is county water. I will have to run a 1/2 mile waterline from the meter, just like everyone else in the subdivision. There is power available, I may need to have a pole or two installed.

I will need to do as much of the work as I can myself, from drawing plans to pulling permits to laying the block walls and framing/finishing to maximize my dollar.

I have building experience and tools, building and remodeling is my favorite hobby. I can't wait to get started, I have been planning this move since 1994!

Is there anything I am forgetting? Does anyone have feedback, constructive criticism or helpful advice?

Mahalo;

Jubilee

[OpenD]

There's a guy in Pahoa who sells Castleblock systems... foam modular block forms you pour concrete into. That's what i would use if I was building today. He's also got other innovative building products, like SIP roof panels that don't require bracing, and roll-material forms for piers. Interesting stuff. Well worth taking to.
Affordable Housing for Hawaii - Castleblock House Packages

Insulation may be irrelevant to you, but it's not necessarily irrelevant to the County or the State anymore. It's a very different building environment now than it was in 1994... or even just 4 years ago. I read recently about somebody in your area having to put in double-pane windows they were not expecting. Everything is in flux right now with the new building code, so be sure to work with a good architect or designer or at least a draftsperson who is up to speed on the changes and is familiar to the staff at the building department in Hilo.

Toughest to swallow for the devout DIYer is that plumbing and electrical work must be done by a licensed contractor. You might be able to find someone to work with who will allow you to do part of that work under their supervision, but don't count on it, and don't expect it to save you much money.

Also, don't assume you know enough from mainland building to meet all the unique challenges of building in Hawai'i. For instance, why are so many houses on the Big Island built with post and pier foundations? Because they are the most flexible foundations, so they handle the frequent seismic activity well. Frequent seismic activity? Like I said, don't assume you know enough from mainland building to meet all the unique challenges of building in Hawai'i.

[Doctor Atomo]

Thanks, OpenD for the link.
I'm up to speed on the requirements of using a licensed plumber and electrician.

I was thinking the downstairs wouldn't need to be insulated as a shop, but yeah... I guess if there is a shower and toilet... I may have to go with the ACC or move the facilities upstairs...

[OpenD]

Originally Posted by Doctor Atomo

Thanks, OpenD for the link.
I'm up to speed on the requirements of using a licensed plumber and electrician.

I was thinking the downstairs wouldn't need to be insulated as a shop, but yeah... I guess if there is a shower and toilet... I may have to go with the ACC or move the facilities upstairs...

That's why I mentioned Castleblock. The foam form stays in place after the pour is completed and provides insulation value.

[CyberCity]

Originally Posted by Doctor Atomo

I am thinking concrete for the first floor for termite resistance as well as wind resistance.

Another thing to think about when deciding on concrete:

The most termite infested house I ever owned was constructed of hollow block tiles. Ground termites used the interior of the tiles as pathways to the roof structure. And they infested the cabinets, baseboards, window casings.

Once we owned the house, we fixed (ie killed/controlled) the problem, but my point is that if you live in an area of ground termites, there is more to their control than just the building materials.

Good luck, we built a small house on the B.I. and it was such an interesting project.

[Doctor Atomo]

Wow CyberCity! That's scary! And informative! Thanks much for the information!
Where did the termites get in? Was the block installed on a concrete footing? Did they ingress through openings?

[CyberCity]

Ground termites can enter into homes through cracks in the cement 1/32 of an inch wide. They will come in through any small crack in your foundation, or cracks that are there from different "pours" of concrete (such as an addition, where one slab meets another). Sometimes they will build mud tunnels on the outside of walls from the ground, and enter the house at the first crack or hole they come to, or build a tunnel all the way to the attic. If there are ground termites, they will get in! The battle is to kill the nest, hopefully before they attack the structure of the house.

One good point about post and pier (in addition to holding up well in earthquakes) is that you can easily inspect for termite activity under the house.

[hotzcatz]

There isn't a lot of savings in putting all your plumbing on one wall and you'll have to live with the design for decades so don't let a $20 savings in a length of pipe change a comfortable design.

[Doctor Atomo]

You are probably right hotzcatz, I'' take that under advisment

[smarino]

Most everyone has given you the right answers. I can only add that post and pier is popular for one very important reason. A lot of the land is hard lava, not dirt. You'll need to find a contractor w/ a huge bulldozer to clear things if you're building w/ a concrete slab, and maybe even for post and pier. It won't be cheap. When I first moved to the BI I would see people mowing their entire yards w/ a weed eater! Wow, why aren't they mowing it w/ a lawn mower I used to wonder? It would be a lot easier and faster. Well, their land was lava, with only a thin surface of dirt and grass, and very uneven. A lawnmower would have gotten it's crankshaft bent in short order after coming into contact w/ that.