Investigating Polystyrene Concrete Composites

(George Hawirko) #1

EPS (Expanded Polystyrene) Composites can provide solutions for many builders and designers of floating structures. Easy to obtain materials make it easy to create models for practice and testing. Proven in many already built homes in worldwide use today.

Cost of building a floating construction facility
(Wilfried Ellmer) #2

Concrete composites - definitly a interesting theme in the context of seasteading. Polystyrene can have a role as ....

  • light filler in the composite
  • as forming material
  • as placeholder for plugs
  • sandwich panel component

Is styrofoam the material “floating cities will be made of” certainly not

| styrofoam block method limits | a styrofoam float definitly misses the point in the investor key conversation.

(George Hawirko) #3

EPS on its own can do the job but a concrete skin will eliminate UV damage along with preservation of the EPS from chipped away by the elements. These Composites are truly “almost” maintenance free as one could expect, with possible lifespans of several decades to several hundred years. Rot and Mold resistance make your health aboard the structure more pleasant.

(John Frederic Kosanke) #4

Non-expanded polystyrene is as strong as PVC - and cheaper. It could make an ideal skin. What I like most about polystyrene is that it is unsinkable - and extremely cheap. It’s also an excellent insulator, which would be a big plus for relatively harsh climates.

(George Hawirko) #5

You might want to consider Flame Prevention also Styrene might not be Insurable on its own because of the fire hazard.

(George Hawirko) #6

(George Hawirko) #7

(John Frederic Kosanke) #8

Not a problem.


I enthusiastically agree. I think EPS is the future of floating cities. It is the one material that is always lighter than water, so even in case of complete structural failure it still floats (as opposed to Concrete or Steel).

Concrete covered EPS is the standard for floating homes in the Northwestern US (Like Seattle) and is now fully insurable by a number of carriers.

Some pictures from my floating city design. The smaller structures are EPS based:

Oceanic business alliance | key player network | ocean colonization | big five | get connected | get invested
(.) #10

The pictures are beautiful. What kind of wave action could these structures take?
Would this be open ocean?

(John Frederic Kosanke) #11

Needless to say, the pictured floating city would need to be in protected waters. Perhaps the breakwater itself could also be made from reinforced polystyrene?


I designed the city based on the DeltaSync plan for the Gulf of Fonseca. So that’s a protected bay and no breakwater is needed. Fonseca is uniquely placed and so there is little hurricane danger.

I’ve revised the design to suggest gyroscopic stabilizers, which are efficient with lighter floating structures. A gyroscope to stabilize the 60x60 float will cost about $6000 and will keep the float level in seas up to about five feet.

In my book, the people leave the gulf to float to Kiribati. That’s the more fictional part of the story. Waves in the equatorial central Pacific run mostly 2-4 feet which should be fine for this scale.

The DeltaSync plan clearly states that breakwaters are not cost efficient. That is; they add no habitable space, and are extraordinarily expensive, and no actual community would undertake a costly structure with so little value. People sail across the ocean all the time without a breakwater. I think any realistic plan for a floating city needs to come to terms with the fact that no breakwater is cost efficient.

The best cost savings is to put your cheaper structures around the outside, and make the low-rent folks ride it out, which is clearly shown in my plan.

(John Frederic Kosanke) #13

Surely you’re not suggesting that this design would be safe in a deep sea environment without some form of wave protection.

The DeltaSync plan aligns with the longer-term mission of TSI to facilitate expansion and migration into the open waters:

“This concept also assesses a scalable method of financing a breakwater, which could eventually surround the city and allow it to move out to the open ocean.”

Many existing breakwater designs use polystyrene, so it is a proven concept.


No resident will be willing to spend $1 million on an apartment, and another $1 million on a breakwater which is completely unnecessary. Besides, no breakwater would be that cheap (only $1 million per resident).

So the only feasible solution is to build a floating city without a breakwater. There’s no other realistic choice. DeltaSync points this out in their report Page 126 titled: Appendix 5 Floating breakwaters: opportunities and challenges.

Breakwaters are also an interesting option because they don’t have to be applied right from the start. When a seastead starts at a bay or other sheltered water surface and is not yet exposed to large waves, there is no need for wave protection. As it grows larger, at a certain point it may be able to finance a breakwater, especially if there is future growth potential. For many alternative options, such as seaworthy ships or semi-submersible rigs, their seakeeping measures are an integral part of the structure and cannot be applied later on.

(.) #15

… good luck …

(George Hawirko) #16

Thanks for this fine example of possibilities that anyone can utilize today, we need this work to continue so that any bugs are exposed early.

(George Hawirko) #17

Surfboards have been around for many years now and the foam boards show us that Foam wrapped in reinforcement can take a punishing existence.

Weather is another problem that should be considered. That force that level Mountains and Climate Change now offers many versions that are unexpected.


@EPSComposite I’m loving your pictures.

You have shown another HUGE feature of EPS coated concrete. It is light. So light that the entire floating structure can be lifted out of the water.

This is important for maintenance. All ocean going vessels must be maintained underneath on a periodic basis. Concrete may last 100 years, but the shellfish that drill into it, spalling or other problems may attack the surface. It will not be easy to drydock a floating city. But lifting one building at a time would be a reasonable solution to the maintenance problem.

So any dwelling that can be lifted clear by a standard marine hoist is desirable. Ship-born hoists go up to about 40 tons. Shore based cranes can handle about three times that. Above that weight and you have no choice but to drydock it which is what is done for large ships. That means floating the structure to a land-based drydock which is very expensive. So staying under 40 tons per platform means that every 20 years you can hoist the house, clean and re-seal the bottom if needed.

(George Hawirko) #19

Then there is the question to Ballast or not to Ballast?


No ballast. I worked on this quite a while and started a thread below on it.

Most ocean going vessels are roughly 1/3 draft (below the water line) and 2/3 freeboard (above the water line.) Ballast helps optimize this ratio. There are notable exceptions. The largest cruise ships have only about 20% draft, with 80% of the vessel above water. The Allure of the Seas also spends almost all it’s time in protected waters like the Gulf of Mexico, venturing onto the Atlantic only during calm summer months.

More draft helps fluid dynamics for a ship in motion. This means nothing for a city. There is no advantage to draft for a floating city.

More freeboard means the city will react more strongly to wind, but also will ride above waves better. The whole need for a breakwater is moderated if most of the water motion passes under the city.

Your picture example shows a canal type houseboat with about a 12" draft. That’s the same as my floating house design pictured above. A 40 ton structure on a 60x60 platform only drafts about 12 inches.

Stability is gained by keeping your wind dynamics clean and in the case of my design, by using marine gyroscopes to stabilize the structure.

I finally concluded that for a floating city, the best draft possible is the least draft.

There is some value to having “solid” feeling walls, so 2lb per square foot EPS on a 6" thick wall would be nice. You don’t want to be able to punch your fist through it, because people would thing it is flimsy. Also concrete on the outside for durability and to keep the fishies from eating the foam. Aside from that, the lighter you are, the more you are free from the subsurface forces of currents and waves.