leak.htm

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    WILL THE

AMERICAN INGENUITY DOME LEAK?

 

Not usually, but if you do have a leak we have found it easier to repair a leak in our concrete dome than it is to make a repair in a shingled roof. Usually caulking or painting is all it takes to seal the dome but stopping a leak in shingles usually requires removing the shingles and starting over.  Use a urethane or latex caulk NOT a silicone caulk.

 

We have domes in 46 states and seven foreign areas.  American Ingenuity Domes excel in very cold climates and they now exist in such cold climate states as Montana, Minnesota, Wisconsin, Michigan, Illinois, Indiana, Missouri, Arkansas, Ohio, New York, New Jersey, Maine, Vermont, Pennsylvania, Canada, and The Northwest Territory, etc. The panel concrete has been especially designed (with liquid admixtures and fibers) to work in cold and hot climates.

 

Concrete is an excellent and common building material in all temperate zones throughout the world. Concrete is only affected by freezing temperatures when it is porous and absorbs water. The richness and density of our concrete prevents water absorption that spoils the surface when it freezes.  Our concrete is also formulated with an air entrainment admixture that further improves the freeze-thaw characteristics.  The exterior concrete primer and latex paint that you apply on site is an additional seal to any water that could freeze inside the concrete.

 

Click on a question to read the answer.

 

What makes your panel concrete so crack resistant?

 

I understand when I mix concrete on site to fill the panel seams, the recipe includes the same liquid admixtures and fibers that you used in the panel concrete.  Is this true?

 

After all the seams and building options are concreted, what is used to seal the concrete?

 

I am considering applying elastomeric paint over the entire dome, should I do this?

 

What if I get a leak in the dome shell?

 

Where am I most likely to get a leak?

 

Explain why the use of a bonding agent helps prevent leaks.

 

What else do I do during the seam concreting to assure that the second layer of concrete bonds to the panel concrete and to the first layer of the seam concrete?

 

What other special features are designed into the panels to improve the bond and strength of your dome?

 

Can I spray concrete into the seams instead of hand applying it?

 

Why is it more beneficial to have preconcreted panels instead of spraying concrete all over the dome on site?

 

What is the curing time for the seam concrete?

 

Click on the photo to enlarge it.

 

                                               

To work on his dome, this                 This dome owner is painting

dome owner sits in a                          his dome with a pole and roller

a harness.                                            and an extension ladder. 

                                                               The dome can be sprayed instead of rolled.

 

Q: What makes your panel concrete so crack resistant?
A:
 The panel concrete is a special formulation containing synthetic fibers and liquid admixtures. These ingredients improve the concrete’s characteristics, create super toughness, extend durability, make concrete impervious to water, give higher tensile and compressive strength, provide elasticity for expansion, and improve freeze protection.  The concrete in your dome out performs other exteriors because of its specially developed formula.  Because of its exceptional composition, it actually gains strength over the years.  The exterior panel concrete adheres directly to the steel mesh and the E.P.S. insulation without the need of a bonding agent.

 

Q: I understand when I mix concrete on site to fill the panel seams, the recipe includes the same liquid admixtures and fibers that you used in the panel concrete.  Is this true?
A:
 Yes, we ship the same liquid admixtures and synthetic fibers with the Building Kit so that the seam concrete you mix on site will have the same properties as the panel concrete.   Fibers in concrete work to reduce the formation of shrinkage cracks in concrete’s plastic state while helping to improve shatter resistance and reduce water migration.  The result: tougher concrete. 

 

The liquid admixtures which are marked A and B are an air entrainment and a water reducer.

 

The Concrete Mix recipe includes water, 1 bag Portland (type 1 or 111), Admixture A, Admixture B, ¼ large bag fibers, Sand (any sand normally used in either concrete or masonry).  The Assembly Manual includes the precise amounts for each of these items.

 

Q: After all the seams and building options are concreted, what is used to seal the concrete?
A:
 Although most of the concrete joints will not leak, we don’t depend on the concrete to make the dome watertight.  The dome gets additional sealing with a concrete primer and latex house paint. After the shell is assembled, a concrete primer is used first then one or two coats of good quality latex paint.  Any porous area that water will penetrate; paint will also soak into and seal.  If a leak persists you can resort to an elastomeric paint in that area or in the very worst case, a stretch cloth and elastomeric paint.

 

Q: I am considering applying elastomeric paint over the entire dome, should I do this?
A:
 No. These are acrylic paints that have a considerable capability of stretching.  They are very useful in sealing the outside of the dome where thermal expansion is most likely (for example where a link connects to the dome).  Most all paints will stop liquid water if there are no holes or cracks, but water vapor (evaporated water) is a gas which will pass fairly easily through most Latex paints. 

 

Elastomeric paints restrict the amount of water vapor which will pass through them.  This can be a disadvantage if there is a lot of water vapor confined inside the dome.  The water vapor will slowly pass through the E.P.S. and go through the concrete and practically come to a stop at the elastomeric paint.  In extreme conditions the paint will bubble or blister and be filled with water which condensed from the original vapor.  The blister is popped to release the water.  It is difficult to repair the blistered area and make the surface match the rest of the dome.

 

Q: What if I get a leak in the dome shell?
A:
 Please call us and ask our advice.  It easier to repair a leak in our concrete dome than it is to make a repair in a shingled roof. Usually caulking or painting is all it takes to seal the dome but stopping a leak in shingles usually requires removing the shingles and starting over.  Use a urethane or latex caulk NOT a silicone caulk.

 

Q: Where am I most likely to get a leak?

A:  Two domes are connected by a passageway that we call a link. A leak most likely will occur where the long flat roof of the link butts up to the curved surface of the dome shell. The expansion and the contraction associated with temperature changes produces the flex or separation at the link. The fall is the most likely problem time. We have tried expansion joints but they are not trouble free either. 

 

You seal that area by using spandex cloth and elastomeric paint.  When you purchase the link, we supply the spandex cloth with the building kit.  First apply a layer of elastomeric paint in the edge where the link and dome meet, lay about a 12" wide strip of spandex cloth (whatever length is appropriate) in the paint, press the spandex down into the paint. Apply two coats of elastomeric paint, letting the paint dry between coats.

 

Q: Explain why the use of a bonding agent helps prevent leaks.
A:
Technology has developed now to prevent cold joints. The assembly manual that comes with the dome kit explains how to utilize bonding agent and other techniques to join the concrete in the seams.  Concrete, or a cement mixture, will not bond to a dry absorbent surface such as dry concrete.  The reason is easy to understand when you examine the curing process of cement.  When new concrete is applied over old, dry concrete the moisture from the new concrete will be absorbed by the dry concrete especially at the surface where they meet.  When the new concrete is robbed of its moisture at the joining surface it will not cure properly and therefore will not bond.

 

Bonding agents are designed to improve the adhesion between layers of concrete by acting as a glue and coating and sealing the dry concrete to prevent it from robbing the moisture.  The bonding agent that is provided with your kit, when mixed with concrete, also increases its strength.

 

Q: What else do I do during the seam concreting to assure that the second layer of concrete bonds to the concrete of the panels and to the first layer of the seam concrete?

A:  This is discussed in detail in the Assembly Manual, but basically you wet the adjacent panels with water and allow them to soak up all the water they will.  Plus you apply bonding agent on the concrete ledge at the edge of the panel and on any concrete that has been placed in the seam.

 

Q: What other special features are designed into the panels of your kit to improve the bond and strength of your dome?

A:  The preconcreted panels have a ledge molded into the edge of the concrete where the seam concrete is most needed to bond.  This ledge increases the bonding surface, thereby increasing the ultimate strength of the joint.  The steel mesh which extends from the old concrete to the new concrete is a small mesh which compliments the effect of the fibers in securing the joint.

 

Q: Can I spray concrete into the seams instead of hand applying it?
A:
No. We do not recommend pumping or spraying the concrete into the dome seams because the equipment usually pumps faster than someone can finish the seams.  The overspray gets on the panels and unless it is washed off ASAP it will harden and be very difficult to remove. 

 

Q: Why is it more beneficial to have preconcreted panels instead of spraying concrete all over the dome on site?
A:
A continuous sprayed concrete structure will cause the concrete to cure all at once causing cracks. Preconcreted panels allow for the panel concrete to cure prior to the seam concrete being applied.

 

In 1976 American Ingenuity manufactured and then built its first geodesic dome prototype by utilizing reinforced concrete over E.P.S. insulation. Steel mesh was hand tied onto propped up E.P.S. insulation, the concrete was then gunited and troweled over the propped up E.P.S. insulation.  Countless designs and manufacturing construction techniques were analyzed in the early years as we developed a new generation in dome housing.  We have outgrown two previous models as we have progressed to a six dome complex. 

 

We do not recommend sprayed concrete structures because spraying concrete causes a waste of labor and concrete. The concrete ends up being 2" thick in one place and 3" to 4" thick in other places. The concrete on the dome needs to be thick only in the seams and thin on the panels. It is a waste of labor because it is difficult for the concrete finishers to stand in the concrete on the side of the dome and try to finish the concrete as it is curing. Also a continuous sprayed concrete structure will cause the concrete to cure all at once causing cracks. Preconcreted panels allow for the panel concrete to cure prior to the seam concrete being applied.

 

 Q: What is the curing time for the seam concrete?

A:  The weather and the mix of the concrete (amount of water, etc) will effect the curing time of the concrete. Usually by the time you place a complete row of panels and are ready to start the next row, the concrete has cured enough.  If you place a panel above another panel and cracks start to form in the first coat of concrete, then the concrete has not cured enough.  You have to stop placing panels until the concrete has cured more. 

 

To apply concrete in the seams the outdoor temperature should be above freezing, preferably at least 40 degrees.  The concrete cannot freeze for two days after the application.

 

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