Old patch
              on dome.
Paint is scraped off.
This nice old dome had been patched quite a few times since 1910. Some of the patches were really well done, like where this band was duplicated.
Most of the paint was easily scraped off. A long as we are down to the unpainted stucco, we can permanently bond a new coat on top.
Old re-coating is scraped off.
gypsum blocks, known as "gypblock"
Where the dome was re-coated before failed, and
the mortar was easily scraped off. They didn't know the secret of Flex-con.
The stucco was done over gypsum blocks, known as "gypblock". These were really made for interior use. Without tearing the whole dome down, we had to find a practical solution for a permanent repair.
gypblock was reinforced with straw.
paint is chipped off
A close up of the gypblock shows it was reinforced with straw. Gypblocks are cast molding plaster, like is used for interior plaster moldings. Some of these gypblocks were made right at the job site, by the plasterers. Some were made by manufacturers, like US Gypsum.
Most of the paint is chipped off using an electric chipping hammer. The chips open the pores in the old stucco for a good bond.
For more about re-coating stucco, please click here.
gypblocks are packed with mortar
ABOVE: All the holes and gaps in the gypblocks are packed with mortar with plenty of Flex-con mixed in. The flex aids not only in bonding, but the mortar develops incedible strength and crack resistance.  The wall will be coated with the
same flex-con mixture. The flex-con also makes the mortar a lot less porous, and water resistant.
For more about Flex-con and chemical bonders,
Please click here.

LEFT: The ladder we climbed every day to get to the dome.

              ladder we climbed every day
Brown coat on the
              dome finished
stucco is cut off
              for metal flashing
Brown coat on the dome finished.
The stucco at the bottom is cut off to insert a metal flashing.
The flashing
                  overlaps the rubber membrane
REAL white portland
The flashing overlaps the rubber membrane below, and is over lapped with mortar.
Finish coat is REAL white portland cement and REAL white sand. After the window returns are finished, we put the finish on the big wall.
Dome finished
Capitol Hill Seventh Day Adventist Church,
              Washington, DC
Dome finished to it's original 1910 splendor.
I hope it lasts longer that 100 years this time.
With a new copper cupola, and new stucco on the dome, Capitol Hill Seventh Day Adventist Church
lights up the corner of 10th and Massachusetts Avenue, NE, Washington, DC.