Functional Fortress

The adobe building I have designed here is an open source design. I intend to build a prototype this summer. If you have any suggestions, please leave a comment or email me at rickspils@excite.com

The perfect home is an island of serenity...

even in a troubled world.

A well designed house should last for generations.

A sustainably designed house should heat and cool itself – passively.

A completely well thought out house should be designed to be bulletproof – literally bulletproof... and flood resistant, and earthquake resistant, and hurricane force wind resistant.

A wisely designed house should be made from inexpensive, locally available natural materials (or with materials that can eventually be recycled).

The ultimate home design will have a deep empowering connection

with the environment.

The Functional Fortress was designed from below ground up – to be sturdy, safe, energy self sufficient, low maintenance, and sustainably made.

…...........................Functional Fortress drawing to be added later...........................

All life gets everything it needs from the Earth and the Sky.

The life that does this best owns the future.

The Functional Fortress was designed to get everything we need from the Earth and the Sky – to create your island of serenity.

Below the Functional Fortress floors:

Temperatures just a few feet below the surface of the Earth approach a constant 57 degrees F. A floor intimately connected thermally to subsurface Earth will be cooler in the Summer and warmer during Winter. This physical state has inspired people to build underground and earth-bermed houses. They work great. But one does not have to bury their home to (passively) heat and cool it from the thermal mass of the Earth.

The Functional Fortress was designed to inexpensively insulate a tunnel to the temperatures of the depths. A mixture of perlite and scoria is buried in a 5 foot deep trench around the base of the building – forming a thermal “moat.” Perlite is an excellent insulator and scoria has many voids for the perlite to fill. Scoria is also structurally sound. This mix is up to 3 feet thick, creating a tunnel of thermal insulation isolating earth temps at the surface from earth temps beneath the building. Therefore, in the Summer, heat will sink into the floor. And in the Winter, heat will source from deep within the Earth.

The Bombproof Adobe walls:

The walls of the Functional Fortress perform more functions than McMansion walls. The most important of these functions is to last – up to hundreds of years... While of course, being a desirable home for as long as the building lasts. Adobe structures have lasted for up to 800 years – and when well maintained, still look great. Moreover; when designed right, adobe is downright practical.

One of the primary features the Functional Fortress walls have is that they store thermal energy. (Most stick built and SIP homes miss out on this feature entirely.)

Actually, the ideal wall should have two thermal skins; an external skin to insulate, and an internal skin to store thermal energy. This way, the temperature fluctuations from day to night can be dampened inside the house while the temperature fluctuations outdoors can be ignored. Of course; if you're going to store thermal energy, you need thermal mass. Adobe is an excellent inexpensive candidate for thermal mass material.

Adobe construction has historically been very labor intensive. One had to make all of the bricks before they could even get started on the building. But that isn't necessary anymore.

Adobe doesn't have to be made into bricks. Much labor can be saved by stuffing adobe into sacks and allowing them to dry in place. This “super-adobe” has shown itself quite strong – and even more stable than traditional homes in earthquakes. A recent design improvement; “hyper-adobe” (see picture) utilizes open mesh tubes – which allows a better bond between the “sacks” – which makes the adobe wall even stronger. But even this design can be improved upon. Bombproof Adobe walls are designed with two rows of 12 inch thick hyper-adobe in steel mesh tubes, reinforced with MgO cement, steel rebar, and fiberglass – on a conventional reinforced concrete foundation. This makes the Functional Fortress adobe walls literally bomb force resistant (of course, the windows and doors won't be – but that can be designed around).

Adobe is a practical and adaptable building material. Mixed with MgO cement, it is water resistant. It can even be modified, with naturally occurring materials, to be used as an insulating layer. Mixed with pumice or perlite, 12 inches of adobe can provide as much as R-30 insulation.

But what's really special about adobe is that it's just hardened dirt... you know; rock. It's not out of place in nature.

And, of course, 24 inches of rock can stop most bullets.

And, of course, rock is fire resistant.

And by the way, if it floods, there is no drywall or wood to get wet. Just mop the Functional Fortress out, and you're ready for the next flood.

The Functional Fortress SIP roof:

The final primary component of the integrated system is the roof. The ideal roof is light and strong. (There isn't enough rainwater here in the high deserts for turf on the roof.)

Stainless steel SIP (Structural Insulated Panels) with polyurethane insulation are the lightest, strongest, least flammable, longest lasting, VOC safest, and best insulating option for ultimate durability. Steel SIP panels have withstood 140 mile an hour hurricane force winds with only minor damage.

On a roof; light, strong, and thermally insulating qualities are best accomplished with materials that can be recycled. (Besides; massive adobe roofs have a history of occasionally collapsing on their inhabitants.)

Structurally, the Functional Fortress roof is designed to stand on its own. It could even be bolted together as a shade, without walls. There are two reasons for this. First, if the roof stands on its own, there are no structural requirements for the adobe walls to meet to hold up the roof. Second, the steel vertical I-beams will help strengthen the adobe walls.

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The ideal fortress only keeps out what you don't want.

Though efficient, the Functional Fortress is not a super-efficient home – by design. Homes need to breath, because those who live in homes need to breath.

• In Summer, vents low on the North side of the house inhale cool shaded air – and vents at the top of the roof exhale hot air.
• In Winter, a solar hot air collector heats outside air and vents it into the house. The fresh air intake is at the bottom of the collector. As the air heats, it rises, and pushes air into the house – with or without a fan. On the other side of the house, the room temperature air is vented to the outdoors – after it is ducted under the porch to melt ice.

Of course, the Functional Fortress is mounted with PV solar modules to generate electric power for the homeowners.

And, of course, the Functional Fortress is passively solar heated. A row of windows on the South facing wall will bring in sunlight and heat in the Winter. The South eave of the roof will shade these windows in the Summer. On top of that, at the crest of the roof is a row of windows facing Southward. Light from these upper windows will heat the back wall. These upper windows are inset beneath the North facing roof so that they too will be shaded by the roof in the Summer.

Again, what makes passive solar heating so special with the Functional Fortress is the huge thermal mass in the interior walls. The massive twelve inch thick adobe interior walls will store solar heat all night – and in the summer, cool a building all day.

The roof crest cooling vents:

The row of roof mounted passive solar windows aren't just to let sunlight in. They are designed to adapt to outside temperatures. In the Summer, there are automatic vents just above the windows that open during the day to vent out hot air. 

 

In the Winter, there are insulating panels that cover the insides of the windows at night to keep warmth from escaping.

The windows work together with ceiling fans to blow warm air out in the Summer – or down towards inhabitants in the Winter.

Actively controlled motorized vents and thermal barriers will significantly increase the home's efficiency and reduce the need for human oversight. However, the vents on the lower North walls will only require passive controls.

The North window/ cooling vents:

During the Summer, the self-functioning automatic hinge (often used on greenhouses) on the exterior vent is temperature sensitive to ventilate during the summer days and close automatically at night. Therefore, the interior windows can be left open all summer (with a bug screen).

In the winter, the lower vents on the North side of the building can be completely closed off by disconnecting the hinges (unscrewing an adjuster). And solid foam insulation can be placed between the window and the vent. In this configuration, the lower widows will function as a well insulated part of the wall in winter.

This window/vent design only requires one to set up the windows twice a year – once in the Spring, once in the Fall.

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Sometimes, the safest fortress doesn't look like a fortress.

With all of the design innovations, one might be led to believe that the Functional Fortress would look significantly different from homes one might find on the market today. Not really.

The bags/tubes that are filled with adobe can be made to look a lot like logs on a log home. And if the builder wants to fill in the rounded shapes with stucco, the walls will just look stuccoed.

The windows and doors will have adobe arches above them (a necessary characteristic of adobe construction).

But, from a distance, if you didn't know the design; you wouldn't notice it standing out.

When you would notice the big difference of the Functional Fortress would be when you enter the home. The walls are two feet thick!

On the inside; the look can be much like traditional adobe homes – or the homeowner can create their own look.

There are design constraints that limit the shapes of the Functional Fortress. A builder cannot just throw one up in any shape or oriented in any direction like most homes today. But when you think about it; that's a sign. That is a sign that the design has been optimized to get the most from the sun.

The Functional Fortress has been optimized for sustainability, durability, economy, and low maintenance comfort for the inhabitants. On the other hand; McMansions are designed to maximize quick profits for the builder.

It's time to rethink why we build.