foundation's | AiDomes

 This page provides info about American Ingenuity domes built on pilings and platform.

8.18 Exterior pilings2 Mowery platform-edited2

40′ dome built in 1990 on concrete platform on concrete block columns.

This concrete dome survived Hurricane Andrew with no damage.

 

40' dome built on pylons extending 12' above ground. This dome survived Hurricane Katrina.

40′ dome built in 1992 on wood pylons extending 12′ above ground.

This dome survived Hurricane Katrina with no damage.

 

The standard foundation that comes with American Ingenuity’s building plans is a concrete slab. For Ai to design any other foundation other than concrete slab, a local Florida licensed engineer is hired.  He requires a soil’s report where the soil engineer recommends what type foundation is to be built for your specific type soil. The local PE engineer uses the soil report data to give Ai details for your foundation design.  He calculates the load of the dome and its interior floors to determine joist size and spacing and wall design.  Ai then incorporates the engineer’s designs into your building plans.  Call our office at 321-639-8777 for engineer pricing.

The dome’s standard footing size is 20″ tall by 16″ wide with slab 4″. Foundation should be built on undisturbed native soil or fill – with soil compacted to 98% density for a minimum of 2,000 psf of bearing pressure. If your bearing capacity is less, then the engineer can increase your footer size and slab thickness. For example the soil for a dome being built in California was 1,500 psf. Its footer was increased to  20″x 20″ and slab was increased to 6″.

Have you checked with your local building department to see what they require your house be built on? If you live near the ocean or body of water, the building department may require concrete or wood pilings which could be driven 10′ to 15′ or more down into the ground versus concrete columns on a footer.

When there is a potential for waves of water washing dirt out from under your house, the local building department usually  requires pilings. If your property is within a few hundred feet of the ocean or gulf then it is the federal government that decides what foundation type your house will have. If you have neighbors that are currently building, ask them what foundations they are utilizing.

Whether you use concrete pilings or concrete columns, Ai can design a wood platform under the dome, wood deck, wood stairs with deck and stairs made out of plastic wood or pressure treated wood. Or Ai can design a concrete platform with concrete stairs. Your building department will require the piling and platform plans and the dome plans to be engineer sealed by an engineer licensed for your state. These seals can be purchased through Ai.

Once you know which types of stilts and platform are acceptable by your building department and soil’s engineer, the next step is to ask the Building Department and or your friends, neighbors, relatives that have built on stilts and a platform for contractor
references.  Contact two or three of these stilts/platform contractors and obtain pricing quotes for a platform the square footage of the dome home you are planning….1,178 sq.ft. for 40′, 916 sq.ft. for 36′, 1,489 sq.ft. for a 45′ dome….adding in whatever deck and patio area that you want.

We think the prices will shock you!  That is why you are shopping types of stilts and platforms and different size domes so you can get an idea of construction costs.  To keep your costs down, we recommend that you build as small a dome as you can because stilts and platform costs can range from $30,000 to $60,000 to $100,000 and that pricing does not include the costs for the dome kit, materials to finish the dome or any labor to assemble the dome kit and finish its interior.  While you are at it, ask the contractors what the approximate cost per sq.ft. is to finish a conventional house in the neighborhood where you are thinking of building.  Once you have this number then you can really decide what size dome you can afford to finish. The dome size will ultimately determine the size of your platform.

If you need to obtain financing, the lender will require 25% to 35% down based on the finished price of your stilts/platform and the dome.  So if you build a 36′ dome (about 1,664 sq.ft.) and the price per sq.ft. to build is $100 and your foundation costs are $60,000 then your finished cost is $226,000.  The lender will want $56,000 to $79,000 down.  They will accept some equity you have in the land, but they will want a lot of cash to be included in the down payment.  Is this down payment within your budget?

We hope we are not bursting your bubble….but over the 39 years that American Ingenuity has been in existence, we have found it better to be up front on the “big picture”; so that our clients do not purchase building plans for too large a size dome and then later not be able to afford to finish their dream home.  To us the single biggest bargain our clients receive is the American Ingenuity Dome building kit…which is usually one third to one half less in cost than the materials cost for the walls and roof of a conventional house or wooden dome or gunited concrete dome…..but this does not mean that all the finishing costs will be one half less.  The kitchen cabinets, doors, windows, plumber, electrician, stilts, platform, etc. all cost the same whether it is a box house or a dome.  So it is best to build the smallest dome you can and even consider not installing the second floor till later.  That way you can afford to finish your dome, live on your  property and save month to month on your heating and cooling costs and have a tornado and hurricane proof house.

As far as selecting a contractor for your dome, we recommend that you get quotes from several builders to compare construction costs….all the time explaining to them that they need to quote based on hiring the Kit Assembly Consultant to supervise their workers to get the shell assembled.  The Consultant can give you an agreement showing the number of days needed for assembly with the first layer of concrete in the seams.  This way the contractor does not need to be worried about estimating the assembly costs and making mistakes during the assembly just because he has never assembled and Ai dome kit before.  Once the dome is erected, and a scratch coat of concrete is in all the seams and on all the entryways and dormers, the Consultant can leave and the contractor’s subs can finish the interior and even finish the last coat of stucco in the seams and on the entryways and dormers. To view info about Consultant, please click on Specialist/Consultant.

Various Questions American Ingenuity receives: 

  1. My property is in a flood zone, what height is the finished fill and finished floor height to be?  If you are in a flood zone, then FEMA requires your finished floor height to be at a certain height. Contact your local Natural Resources government department and ask them for the FEMA phone number and what info you have to provide the County when you submit for your building permit.
  2. I might have wetlands on my property, what do I do to build?  Contact your government office for who to contact to see where the wetlands are and determine how much of the property is buildable.  Find out the set backs on your property to see what size of property is left to build on.  If you need to install septic tank and drain field and well then there are  setbacks from those as well.  Ultimately you end up with a site map showing your driveway, set backs, septic, well or city water & sewer line, etc.
  3. I think I need to build my foundation off the ground.   First of all, how high off the ground does the first floor have to be? If you do not know this answer, you will need to  call your building department and ask them.

Possible Solutions

  • If your dome has to be eight feet to ten feet off the ground Due to a wave of water, not rising water then the dome will have to be built on concrete columns and a concrete or wood platform
  • If you want enclosed rooms or a garage under the platform, then you can install break-a-way basement walls. Build concrete block columns under the corners of the platform.
  • If your dome has to be raised two to three feet, the best thing may be to bring in fill and construct the concrete slab onto the fill.
  • If your dome has to be raised two to three feet build a stem wall: bring in fill to fill within the stem wall and pour a concrete slab onto of the fill (most economical and energy efficient)  install a wood floor that sets on piers and beams. You would have a crawl space. (more expensive)

Q: In my area I have to deal with the possibility of a wave surge, can I build my dome on “break away basement walls”?
A: Yes. If you have to design with the possibility of a wave surge, you may be able to enclose the first floor pilings with breakaway walls. Breakaway walls are nonstructural walls that will break-a-way in the event of a wave surge. Pilings (columns) would support the structure and the breakaway walls could be installed between the pilings to enclose the ground floor. The purpose is to enclose the ground floor but preserve the house if a wave tears down the walls.

Q: In my area I have to build on pilings and a platform. Can the dome be built on pilings and still maintain its structural integrity?
A: Yes, building our dome upon pilings does not effect the dome’s structural integrity. We can design the pilings and the  platform, but you will need an engineer licensed for your state to seal the Piling Blueprints. For example, the Building Plans  Cost for the pilings and concrete platform for a 45′ dome could be more than $2,000…..this pricing does not include the building plans for the 45 dome home itself.  We know of a Florida engineer who charges from $1,000 to $2,000 to seal the pilings and platform plan.

If you built the dome on the ground using a concrete slab, the standard dome building plans contain the slab foundation.  As a result you are paying for the building plans and the engineer’s fee to seal the plans for your state.  All the costs associated with elevating any house onto pilings is considerable more and worth considering other options.

For a complete summary of all types of foundations that can be used with the American Ingenuity Dome, click on this link
Foundation Summary.

                          

                                                            CONCRETE PILINGS AND CONCRETE PLATFORM

piling20mowery0061

piling220mowery0062 piling320mowery0063
            This Ai Dome Home with a Cupola was built in mid 80’s. The Cupola’s look is different now; it is
             not so tall and it has overhangs that extend out from the top panels. These raised seams collect
                    water. Only have flat, rounded or accentuated seams on your dome; not raised seams.
piling420mowery0064
                        Pilings with oval Concrete Platform for 40′ Dome Home
 
This page gives info about foundation excavation, types of foundations American Ingenuity design team can design and foundation resource.
For information on foundations used for the American Ingenuity Domes click on Foundation Summary, Concrete SlabPilings, Basements  and  Raised Wood Floor.  American Ingenuity Domes can be built utilizing the same foundation choices as conventional housing.
The foundation types that Ai designs are a) a monolithic concrete slab; b) poured footing with a stem wall and then a poured slab on fill;  c) poured footing with a stem wall and then a raised wood floor; d) basement and; e) pilings and a platform. The type of foundation that is built for your new home will depend on which is more advantageous for your area and what you soil’s report requires.
For American Ingenuity to design any foundation other than our standard monolithic concrete slab, we must hire a local engineer.  The engineer wants to view your soil report.  In the soil report a soil’s engineer will analyze your soil tests and recommend the type foundation that should be built.  The engineer uses this data to provide Ai information & details to be included in your foundation design.
About soil compaction:  Generally the soil under the foundation is compacted to 98% density for a minimum of 2000 pounds per square foot of bearing pressure.  Clean, compacted fill with no subsurface vegetation or voids.  If your soil cannot compact to 2,000 psf, then the footer will be designer larger and the slab might be 6′ thick instead of 4″ thick if acceptable by your building department.
Misc. Foundation Info

The following information came from the book, The Complete Idiot’s Guide to Building Your Own Home, second edition by Dan Ramsey. Any sentences that are in italics were added by American Ingenuity.

Excavating for the Foundation:

Houses require foundations. Why? Foundations support and stabilize the walls and roof. That’s a pretty important job! Excavation is the removal of soil to make room for the building’s foundation. So before excavating, let’s learn about foundations.

The foundation itself needs a foundation. Most houses are so heavy that the foundation must be widened at the base to keep it from sinking into the ground. (An American Ingenuity Dome shell weights less than a conventional house shell due to the thin concrete on its panels.) The wide part of a foundation is called the footing. Its size depends on the kind of soil under it. Most footings are designed to carry 1,000 pounds per square foot. A two-story house will have a wider foundation footing than a single-story house. Typically, the footing is twice as wide as the wall. That is, the footing for an 8-inch foundation walls is usually 16 inches wide. However, don’t go by this; go by your house’s foundation plan.

The foundation wall can be just 1 foot tall or it can be, with support, 10 feet tall or more. Or it can be shorter on one side and taller on another. It just needs to be level on top where the floor will be installed, which I’ll tell you about in the next chapter.

How tall and wide is the foundation for your home? Refer to the foundation plans approved by your building department. It will include the foundation’s layout, dimensions, size, elevation and height.

A slab foundation is a solid floor set directly on the soil. Most modern garage floors are concrete slabs with a continuous wall foundation around the perimeter.

A pier foundation is a series of concrete piers and footings that support the structure. If made of pressure-treated wood, it’s called a pole or post foundation.

It’s important to know the type and size of the foundation now because it tells you what soil needs to be removed or excavated for the foundation. It’s best not to remove any more compacted soil than necessary when excavating for a foundation. The more the earth has been disturbed, the more difficult it is to ensure that the foundation won’t move in the future.

Valuable resources as you excavate for and install your home’s foundation include the following:

  • Local building department
  • Building material suppliers
  • Excavation contractors
  • Transit-mix concrete suppliers
  • Foundation contractors
  • Backhoe and loader operators
  • Construction engineers
  • Concrete block manufacturers and suppliers
  • Construction tool rental yards
  • Alternative foundation sources (treated lumber, stone)
  • The many websites, books, videos, and magazines listed in Appendix B

If you want to know even more about foundations, check bookstores or www.MulliganBooks.com for a copy of my book Builder’s Guide to Foundations and Floor Framing (see Appendix B). It includes lots of illustrations, tables, and in-depth information on all types of residential and light commercial foundations.