Larry built his Monolithic style garage dome by putting up the rebar armature first. This was then covered with chicken wire. Next, he tried shooting against a wooden frame for backing, which didn’t work very well.
After this experience, Larry decided to experiment with some billboard vinyl he had on hand. He took one section of billboard vinyl 7 1/2 feet wide, and wrapped it about 2/3 around the dome. This really improved the efficiency of his progress. Next the vinyl was taken down to spray the outside of his form. There were voids behind the rebar which seemed impossible to get around. These were cleaned out and sprayed over while the mortar was still soft.
The final result was a good sized garage which is pictured below.
We’ve also been following the construction of a Monolithic Dome south
of Eugene, Oregon. This dome uses balloon form technology to
make the shape of the structure.
After the balloon was inflated, polyurethane insulation was sprayed inside the structure
to stiffen the form. Wayne Previti’s crew from East And West
Concrete then placed the rebar according to the plans. Extra reinforcement
was used around the doors and windows.
Their shotcrete was mixed on site using ten buckets of sand, one-and-a-half buckets of water, and two bags of
concrete in each batch.
Above, you see Wayne Previti spraying the final layer of concrete, bringing it out to fit the custom made rods.
The photo above here shows Jorje beginning to trowel the inside of the dome.
This is where the shotcrete is being mixed. On the left
you can see the dump truck that brings the sand in. On
the right the mortar mixer that is high enough to pour into
the pump.
More information on Thin Shell Construction.
